From ff6cf12cd4c30d89650b7f7fffc089c17e9d4842 Mon Sep 17 00:00:00 2001
From: Stuart Montgomery <smontgomery@apple.com>
Date: Mon, 27 Jan 2025 17:04:40 -0600
Subject: [PATCH 01/32] Introduce a severity level for issues, and a 'warning'
 severity

---
 .../Testing/ABI/EntryPoints/EntryPoint.swift  |  2 +-
 .../Event.ConsoleOutputRecorder.swift         |  2 +-
 .../Event.HumanReadableOutputRecorder.swift   | 81 ++++++++++++++-----
 .../Events/Recorder/Event.Symbol.swift        | 10 ++-
 Sources/Testing/Issues/Issue.swift            | 59 +++++++++++++-
 Tests/TestingTests/IssueTests.swift           |  6 +-
 6 files changed, 126 insertions(+), 34 deletions(-)

diff --git a/Sources/Testing/ABI/EntryPoints/EntryPoint.swift b/Sources/Testing/ABI/EntryPoints/EntryPoint.swift
index a0a5df2a0..254311968 100644
--- a/Sources/Testing/ABI/EntryPoints/EntryPoint.swift
+++ b/Sources/Testing/ABI/EntryPoints/EntryPoint.swift
@@ -40,7 +40,7 @@ func entryPoint(passing args: __CommandLineArguments_v0?, eventHandler: Event.Ha
 
     // Set up the event handler.
     configuration.eventHandler = { [oldEventHandler = configuration.eventHandler] event, context in
-      if case let .issueRecorded(issue) = event.kind, !issue.isKnown {
+      if case let .issueRecorded(issue) = event.kind, !issue.isKnown, issue.severity >= .error {
         exitCode.withLock { exitCode in
           exitCode = EXIT_FAILURE
         }
diff --git a/Sources/Testing/Events/Recorder/Event.ConsoleOutputRecorder.swift b/Sources/Testing/Events/Recorder/Event.ConsoleOutputRecorder.swift
index cce3a732c..d89f855e4 100644
--- a/Sources/Testing/Events/Recorder/Event.ConsoleOutputRecorder.swift
+++ b/Sources/Testing/Events/Recorder/Event.ConsoleOutputRecorder.swift
@@ -354,7 +354,7 @@ extension Event.ConsoleOutputRecorder {
   ///
   /// The caller is responsible for presenting this message to the user.
   static func warning(_ message: String, options: Event.ConsoleOutputRecorder.Options) -> String {
-    let symbol = Event.Symbol.warning.stringValue(options: options)
+    let symbol = Event.Symbol.warning().stringValue(options: options)
     return "\(symbol) \(message)\n"
   }
 }
diff --git a/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift b/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift
index 98303f11c..824ec53b5 100644
--- a/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift
+++ b/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift
@@ -56,8 +56,11 @@ extension Event {
         /// The instant at which the test started.
         var startInstant: Test.Clock.Instant
 
-        /// The number of issues recorded for the test.
-        var issueCount = 0
+        /// The number of issues with error severity recorded for the test.
+        var errorIssueCount = 0
+
+        /// The number of issues with warning severity recorded for the test.
+        var warningIssueCount = 0
 
         /// The number of known issues recorded for the test.
         var knownIssueCount = 0
@@ -114,27 +117,36 @@ extension Event.HumanReadableOutputRecorder {
   ///   - graph: The graph to walk while counting issues.
   ///
   /// - Returns: A tuple containing the number of issues recorded in `graph`.
-  private func _issueCounts(in graph: Graph<String, Event.HumanReadableOutputRecorder._Context.TestData?>?) -> (issueCount: Int, knownIssueCount: Int, totalIssueCount: Int, description: String) {
+  private func _issueCounts(in graph: Graph<String, Event.HumanReadableOutputRecorder._Context.TestData?>?) -> (errorIssueCount: Int, warningIssueCount: Int, knownIssueCount: Int, totalIssueCount: Int, description: String) {
     guard let graph else {
-      return (0, 0, 0, "")
+      return (0, 0, 0, 0, "")
     }
-    let issueCount = graph.compactMap(\.value?.issueCount).reduce(into: 0, +=)
+    let errorIssueCount = graph.compactMap(\.value?.errorIssueCount).reduce(into: 0, +=)
+    let warningIssueCount = graph.compactMap(\.value?.warningIssueCount).reduce(into: 0, +=)
     let knownIssueCount = graph.compactMap(\.value?.knownIssueCount).reduce(into: 0, +=)
-    let totalIssueCount = issueCount + knownIssueCount
+    let totalIssueCount = errorIssueCount + warningIssueCount + knownIssueCount
 
     // Construct a string describing the issue counts.
-    let description = switch (issueCount > 0, knownIssueCount > 0) {
-    case (true, true):
+    let description = switch (errorIssueCount > 0, warningIssueCount > 0, knownIssueCount > 0) {
+    case (true, true, true):
+      " with \(totalIssueCount.counting("issue")) (including \(warningIssueCount.counting("warning")) and \(knownIssueCount.counting("known issue")))"
+    case (true, false, true):
       " with \(totalIssueCount.counting("issue")) (including \(knownIssueCount.counting("known issue")))"
-    case (false, true):
+    case (false, true, true):
+      " with \(warningIssueCount.counting("warning")) and \(knownIssueCount.counting("known issue"))"
+    case (false, false, true):
       " with \(knownIssueCount.counting("known issue"))"
-    case (true, false):
+    case (true, true, false):
+      " with \(totalIssueCount.counting("issue")) (including \(warningIssueCount.counting("warning")))"
+    case (true, false, false):
       " with \(totalIssueCount.counting("issue"))"
-    case(false, false):
+    case(false, true, false):
+      " with \(warningIssueCount.counting("warning"))"
+    case(false, false, false):
       ""
     }
 
-    return (issueCount, knownIssueCount, totalIssueCount,  description)
+    return (errorIssueCount, warningIssueCount, knownIssueCount, totalIssueCount,  description)
   }
 }
 
@@ -267,7 +279,12 @@ extension Event.HumanReadableOutputRecorder {
         if issue.isKnown {
           testData.knownIssueCount += 1
         } else {
-          testData.issueCount += 1
+          switch issue.severity {
+          case .warning:
+            testData.warningIssueCount += 1
+          case .error:
+            testData.errorIssueCount += 1
+          }
         }
         context.testData[id] = testData
 
@@ -355,15 +372,22 @@ extension Event.HumanReadableOutputRecorder {
       let testData = testDataGraph?.value ?? .init(startInstant: instant)
       let issues = _issueCounts(in: testDataGraph)
       let duration = testData.startInstant.descriptionOfDuration(to: instant)
-      return if issues.issueCount > 0 {
+      return if issues.errorIssueCount > 0 {
         CollectionOfOne(
           Message(
             symbol: .fail,
             stringValue: "\(_capitalizedTitle(for: test)) \(testName) failed after \(duration)\(issues.description)."
           )
         ) + _formattedComments(for: test)
+      } else if issues.warningIssueCount > 0 {
+        [
+          Message(
+           symbol: .warning(warningIssueCount: issues.warningIssueCount),
+           stringValue: "\(_capitalizedTitle(for: test)) \(testName) passed after \(duration)\(issues.description)."
+         )
+       ]
       } else {
-         [
+        [
           Message(
             symbol: .pass(knownIssueCount: issues.knownIssueCount),
             stringValue: "\(_capitalizedTitle(for: test)) \(testName) passed after \(duration)\(issues.description)."
@@ -400,13 +424,19 @@ extension Event.HumanReadableOutputRecorder {
         ""
       }
       let symbol: Event.Symbol
-      let known: String
+      let introducer: String
       if issue.isKnown {
         symbol = .pass(knownIssueCount: 1)
-        known = " known"
+        introducer = "a known"
       } else {
-        symbol = .fail
-        known = "n"
+        switch issue.severity {
+        case .warning:
+          symbol = .warning(warningIssueCount: 1)
+          introducer = "a warning"
+        case .error:
+          symbol = .fail
+          introducer = "an"
+        }
       }
 
       var additionalMessages = [Message]()
@@ -435,13 +465,13 @@ extension Event.HumanReadableOutputRecorder {
       let primaryMessage: Message = if parameterCount == 0 {
         Message(
           symbol: symbol,
-          stringValue: "\(_capitalizedTitle(for: test)) \(testName) recorded a\(known) issue\(atSourceLocation): \(issue.kind)",
+          stringValue: "\(_capitalizedTitle(for: test)) \(testName) recorded \(introducer) issue\(atSourceLocation): \(issue.kind)",
           conciseStringValue: String(describing: issue.kind)
         )
       } else {
         Message(
           symbol: symbol,
-          stringValue: "\(_capitalizedTitle(for: test)) \(testName) recorded a\(known) issue with \(parameterCount.counting("argument")) \(labeledArguments)\(atSourceLocation): \(issue.kind)",
+          stringValue: "\(_capitalizedTitle(for: test)) \(testName) recorded \(introducer) issue with \(parameterCount.counting("argument")) \(labeledArguments)\(atSourceLocation): \(issue.kind)",
           conciseStringValue: String(describing: issue.kind)
         )
       }
@@ -498,13 +528,20 @@ extension Event.HumanReadableOutputRecorder {
       let runStartInstant = context.runStartInstant ?? instant
       let duration = runStartInstant.descriptionOfDuration(to: instant)
 
-      return if issues.issueCount > 0 {
+      return if issues.errorIssueCount > 0 {
         [
           Message(
             symbol: .fail,
             stringValue: "Test run with \(testCount.counting("test")) failed after \(duration)\(issues.description)."
           )
         ]
+      } else if issues.warningIssueCount > 0 {
+        [
+          Message(
+            symbol: .warning(warningIssueCount: issues.warningIssueCount),
+            stringValue: "Test run with \(testCount.counting("test")) passed after \(duration)\(issues.description)."
+          )
+        ]
       } else {
         [
           Message(
diff --git a/Sources/Testing/Events/Recorder/Event.Symbol.swift b/Sources/Testing/Events/Recorder/Event.Symbol.swift
index 0f50ed95c..d956c3faa 100644
--- a/Sources/Testing/Events/Recorder/Event.Symbol.swift
+++ b/Sources/Testing/Events/Recorder/Event.Symbol.swift
@@ -22,8 +22,8 @@ extension Event {
     /// The symbol to use when a test passes.
     ///
     /// - Parameters:
-    ///   - knownIssueCount: The number of known issues encountered by the end
-    ///     of the test.
+    ///   - knownIssueCount: The number of known issues recorded for the test.
+    ///     The default value is `0`.
     case pass(knownIssueCount: Int = 0)
 
     /// The symbol to use when a test fails.
@@ -34,7 +34,11 @@ extension Event {
 
     /// A warning or caution symbol to use when the developer should be aware of
     /// some condition.
-    case warning
+    ///
+    /// - Parameters:
+    ///   - warningIssueCount: The number of issues with warning severity
+    ///     recorded for the test. The default value is `0`.
+    case warning(warningIssueCount: Int = 0)
 
     /// The symbol to use when presenting details about an event to the user.
     case details
diff --git a/Sources/Testing/Issues/Issue.swift b/Sources/Testing/Issues/Issue.swift
index dae58400a..18d1322a0 100644
--- a/Sources/Testing/Issues/Issue.swift
+++ b/Sources/Testing/Issues/Issue.swift
@@ -79,6 +79,35 @@ public struct Issue: Sendable {
   /// The kind of issue this value represents.
   public var kind: Kind
 
+  /// An enumeration representing the level of severity of a recorded issue.
+  ///
+  /// The supported levels, in decreasing order of severity, are:
+  ///
+  /// - ``error``
+  /// - ``warning``
+  @_spi(Experimental)
+  public enum Severity: Sendable {
+    /// The severity level representing an issue which may be a concern but is
+    /// not an error.
+    ///
+    /// An issue with warning severity does not cause the test it's associated
+    /// with to be marked as a failure, but is noted in the results.
+    case warning
+
+    /// The severity level representing an issue which represents an error in a
+    /// test.
+    ///
+    /// An issue with error severity causes the test it's associated with to be
+    /// marked as a failure.
+    case error
+  }
+
+  /// The severity of this issue.
+  ///
+  /// The default value of this property is ``Severity-swift.enum/error``.
+  @_spi(Experimental)
+  public var severity: Severity = .error
+
   /// Any comments provided by the developer and associated with this issue.
   ///
   /// If no comment was supplied when the issue occurred, the value of this
@@ -97,12 +126,15 @@ public struct Issue: Sendable {
   ///
   /// - Parameters:
   ///   - kind: The kind of issue this value represents.
+  ///   - severity: The severity of this issue. The default value is
+  ///     ``Severity-swift.enum/error``.
   ///   - comments: An array of comments describing the issue. This array may be
   ///     empty.
   ///   - sourceContext: A ``SourceContext`` indicating where and how this issue
   ///     occurred.
   init(
     kind: Kind,
+    severity: Severity = .error,
     comments: [Comment],
     sourceContext: SourceContext
   ) {
@@ -154,6 +186,8 @@ public struct Issue: Sendable {
   }
 }
 
+extension Issue.Severity: Comparable {}
+
 // MARK: - CustomStringConvertible, CustomDebugStringConvertible
 
 extension Issue: CustomStringConvertible, CustomDebugStringConvertible {
@@ -164,7 +198,7 @@ extension Issue: CustomStringConvertible, CustomDebugStringConvertible {
     let joinedComments = comments.lazy
       .map(\.rawValue)
       .joined(separator: "\n")
-    return "\(kind): \(joinedComments)"
+    return "\(severity): \(kind): \(joinedComments)"
   }
 
   public var debugDescription: String {
@@ -174,7 +208,7 @@ extension Issue: CustomStringConvertible, CustomDebugStringConvertible {
     let joinedComments: String = comments.lazy
       .map(\.rawValue)
       .joined(separator: "\n")
-    return "\(kind)\(sourceLocation.map { " at \($0)" } ?? ""): \(joinedComments)"
+    return "\(severity): \(kind)\(sourceLocation.map { " at \($0)" } ?? ""): \(joinedComments)"
   }
 }
 
@@ -234,6 +268,17 @@ extension Issue.Kind: CustomStringConvertible {
   }
 }
 
+extension Issue.Severity: CustomStringConvertible {
+  public var description: String {
+    switch self {
+    case .warning:
+      "warning"
+    case .error:
+      "error"
+    }
+  }
+}
+
 #if !SWT_NO_SNAPSHOT_TYPES
 // MARK: - Snapshotting
 
@@ -244,6 +289,9 @@ extension Issue {
     /// The kind of issue this value represents.
     public var kind: Kind.Snapshot
 
+    @_spi(Experimental)
+    public var severity: Severity
+
     /// Any comments provided by the developer and associated with this issue.
     ///
     /// If no comment was supplied when the issue occurred, the value of this
@@ -268,6 +316,7 @@ extension Issue {
         self.kind = Issue.Kind.Snapshot(snapshotting: issue.kind)
         self.comments = issue.comments
       }
+      self.severity = issue.severity
       self.sourceContext = issue.sourceContext
       self.isKnown = issue.isKnown
     }
@@ -295,6 +344,8 @@ extension Issue {
   }
 }
 
+extension Issue.Severity: Codable {}
+
 extension Issue.Kind {
   /// Serializable kinds of issues which may be recorded.
   @_spi(ForToolsIntegrationOnly)
@@ -484,7 +535,7 @@ extension Issue.Snapshot: CustomStringConvertible, CustomDebugStringConvertible
     let joinedComments = comments.lazy
       .map(\.rawValue)
       .joined(separator: "\n")
-    return "\(kind): \(joinedComments)"
+    return "\(severity): \(kind): \(joinedComments)"
   }
 
   public var debugDescription: String {
@@ -494,7 +545,7 @@ extension Issue.Snapshot: CustomStringConvertible, CustomDebugStringConvertible
     let joinedComments: String = comments.lazy
       .map(\.rawValue)
       .joined(separator: "\n")
-    return "\(kind)\(sourceLocation.map { " at \($0)" } ?? ""): \(joinedComments)"
+    return "\(severity): \(kind)\(sourceLocation.map { " at \($0)" } ?? ""): \(joinedComments)"
   }
 }
 
diff --git a/Tests/TestingTests/IssueTests.swift b/Tests/TestingTests/IssueTests.swift
index 4a4fda631..cdcf9f3b1 100644
--- a/Tests/TestingTests/IssueTests.swift
+++ b/Tests/TestingTests/IssueTests.swift
@@ -1124,12 +1124,12 @@ final class IssueTests: XCTestCase {
     do {
       let sourceLocation = SourceLocation.init(fileID: "FakeModule/FakeFile.swift", filePath: "", line: 9999, column: 1)
       let issue = Issue(kind: .system, comments: ["Some issue"], sourceContext: SourceContext(sourceLocation: sourceLocation))
-      XCTAssertEqual(issue.description, "A system failure occurred: Some issue")
-      XCTAssertEqual(issue.debugDescription, "A system failure occurred at FakeFile.swift:9999:1: Some issue")
+      XCTAssertEqual(issue.description, "error: A system failure occurred: Some issue")
+      XCTAssertEqual(issue.debugDescription, "error: A system failure occurred at FakeFile.swift:9999:1: Some issue")
     }
     do {
       let issue = Issue(kind: .system, comments: ["Some issue"], sourceContext: SourceContext(sourceLocation: nil))
-      XCTAssertEqual(issue.debugDescription, "A system failure occurred: Some issue")
+      XCTAssertEqual(issue.debugDescription, "error: A system failure occurred: Some issue")
     }
   }
 

From e81ce3d7983ffa32dee13346a3cfc9c8abfe144f Mon Sep 17 00:00:00 2001
From: Stuart Montgomery <smontgomery@apple.com>
Date: Mon, 27 Jan 2025 17:33:41 -0600
Subject: [PATCH 02/32] Improve wording

---
 Sources/Testing/Issues/Issue.swift | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/Sources/Testing/Issues/Issue.swift b/Sources/Testing/Issues/Issue.swift
index 18d1322a0..c3dafd0f1 100644
--- a/Sources/Testing/Issues/Issue.swift
+++ b/Sources/Testing/Issues/Issue.swift
@@ -87,15 +87,14 @@ public struct Issue: Sendable {
   /// - ``warning``
   @_spi(Experimental)
   public enum Severity: Sendable {
-    /// The severity level representing an issue which may be a concern but is
-    /// not an error.
+    /// The severity level for an issue which should be noted but is not
+    /// necessarily an error.
     ///
     /// An issue with warning severity does not cause the test it's associated
     /// with to be marked as a failure, but is noted in the results.
     case warning
 
-    /// The severity level representing an issue which represents an error in a
-    /// test.
+    /// The severity level for an issue which represents an error in a test.
     ///
     /// An issue with error severity causes the test it's associated with to be
     /// marked as a failure.

From 8415b9047b52f8f9793168b55edd9d23cac5ffa0 Mon Sep 17 00:00:00 2001
From: Stuart Montgomery <smontgomery@apple.com>
Date: Tue, 28 Jan 2025 10:43:15 -0600
Subject: [PATCH 03/32] Add missing documentation to Snapshot property

---
 Sources/Testing/Issues/Issue.swift | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Sources/Testing/Issues/Issue.swift b/Sources/Testing/Issues/Issue.swift
index c3dafd0f1..23d131d93 100644
--- a/Sources/Testing/Issues/Issue.swift
+++ b/Sources/Testing/Issues/Issue.swift
@@ -288,6 +288,7 @@ extension Issue {
     /// The kind of issue this value represents.
     public var kind: Kind.Snapshot
 
+    /// The severity of this issue.
     @_spi(Experimental)
     public var severity: Severity
 

From 11dec4b44b23ab370da3c41b61365cf12d6dec28 Mon Sep 17 00:00:00 2001
From: Stuart Montgomery <smontgomery@apple.com>
Date: Tue, 28 Jan 2025 10:43:27 -0600
Subject: [PATCH 04/32] Describe the cases in increasing order instead of
 decreasing

---
 Sources/Testing/Issues/Issue.swift | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Sources/Testing/Issues/Issue.swift b/Sources/Testing/Issues/Issue.swift
index 23d131d93..e161adfcc 100644
--- a/Sources/Testing/Issues/Issue.swift
+++ b/Sources/Testing/Issues/Issue.swift
@@ -81,10 +81,10 @@ public struct Issue: Sendable {
 
   /// An enumeration representing the level of severity of a recorded issue.
   ///
-  /// The supported levels, in decreasing order of severity, are:
+  /// The supported levels, in increasing order of severity, are:
   ///
-  /// - ``error``
   /// - ``warning``
+  /// - ``error``
   @_spi(Experimental)
   public enum Severity: Sendable {
     /// The severity level for an issue which should be noted but is not

From 671536269f44e3a475656d91ca521b27161958c7 Mon Sep 17 00:00:00 2001
From: Stuart Montgomery <smontgomery@apple.com>
Date: Tue, 28 Jan 2025 10:43:54 -0600
Subject: [PATCH 05/32] Add severity to the ABIv0 JSON, as private initially

---
 Documentation/ABI/JSON.md                     | 10 ++++++++++
 .../ABI/v0/Encoded/ABIv0.EncodedIssue.swift   | 19 +++++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/Documentation/ABI/JSON.md b/Documentation/ABI/JSON.md
index 23dd5b1dc..0a97c9e68 100644
--- a/Documentation/ABI/JSON.md
+++ b/Documentation/ABI/JSON.md
@@ -197,10 +197,20 @@ sufficient information to display the event in a human-readable format.
   "runEnded" ; additional event kinds may be added in the future
 
 <issue> ::= {
+<!--
+  TODO: Publicize the severity field.
+  "severity" ::= <issue-severity>, ; the severity of the issue
+-->
   "isKnown": <bool>, ; is this a known issue or not?
   ["sourceLocation": <source-location>,] ; where the issue occurred, if known
 }
 
+<!--
+  TODO: Publicize the severity field.
+<issue-severity> ::= "warning" | "error" ; additional severity levels may be
+                                         ; added in the future
+-->
+
 <message> ::= {
   "symbol": <message-symbol>,
   "text": <string>, ; the human-readable text of this message
diff --git a/Sources/Testing/ABI/v0/Encoded/ABIv0.EncodedIssue.swift b/Sources/Testing/ABI/v0/Encoded/ABIv0.EncodedIssue.swift
index 2bf1c8462..7c5b5185a 100644
--- a/Sources/Testing/ABI/v0/Encoded/ABIv0.EncodedIssue.swift
+++ b/Sources/Testing/ABI/v0/Encoded/ABIv0.EncodedIssue.swift
@@ -16,6 +16,19 @@ extension ABIv0 {
   /// assists in converting values to JSON; clients that consume this JSON are
   /// expected to write their own decoders.
   struct EncodedIssue: Sendable {
+    /// An enumeration representing the level of severity of a recorded issue.
+    ///
+    /// For descriptions of individual cases, see ``Issue/Severity-swift.enum``.
+    enum Severity: String {
+      case warning
+      case error
+    }
+
+    /// The severity of this issue.
+    ///
+    /// - Warning: Severity is not yet part of the JSON schema.
+    var _severity: Severity
+
     /// Whether or not this issue is known to occur.
     var isKnown: Bool
 
@@ -33,6 +46,11 @@ extension ABIv0 {
     var _error: EncodedError?
 
     init(encoding issue: borrowing Issue, in eventContext: borrowing Event.Context) {
+      _severity = switch issue.severity {
+      case .warning: .warning
+      case .error: .error
+      }
+
       isKnown = issue.isKnown
       sourceLocation = issue.sourceLocation
       if let backtrace = issue.sourceContext.backtrace {
@@ -48,3 +66,4 @@ extension ABIv0 {
 // MARK: - Codable
 
 extension ABIv0.EncodedIssue: Codable {}
+extension ABIv0.EncodedIssue.Severity: Codable {}

From 7cdfeb2031255593167007f461ed84d126f484ff Mon Sep 17 00:00:00 2001
From: Stuart Montgomery <smontgomery@apple.com>
Date: Tue, 28 Jan 2025 10:47:27 -0600
Subject: [PATCH 06/32] We don't need to pass the count of warning issues in
 the symbol

---
 .../Events/Recorder/Event.ConsoleOutputRecorder.swift       | 2 +-
 .../Events/Recorder/Event.HumanReadableOutputRecorder.swift | 6 +++---
 Sources/Testing/Events/Recorder/Event.Symbol.swift          | 6 +-----
 3 files changed, 5 insertions(+), 9 deletions(-)

diff --git a/Sources/Testing/Events/Recorder/Event.ConsoleOutputRecorder.swift b/Sources/Testing/Events/Recorder/Event.ConsoleOutputRecorder.swift
index d89f855e4..cce3a732c 100644
--- a/Sources/Testing/Events/Recorder/Event.ConsoleOutputRecorder.swift
+++ b/Sources/Testing/Events/Recorder/Event.ConsoleOutputRecorder.swift
@@ -354,7 +354,7 @@ extension Event.ConsoleOutputRecorder {
   ///
   /// The caller is responsible for presenting this message to the user.
   static func warning(_ message: String, options: Event.ConsoleOutputRecorder.Options) -> String {
-    let symbol = Event.Symbol.warning().stringValue(options: options)
+    let symbol = Event.Symbol.warning.stringValue(options: options)
     return "\(symbol) \(message)\n"
   }
 }
diff --git a/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift b/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift
index 824ec53b5..e2fcaeafb 100644
--- a/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift
+++ b/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift
@@ -382,7 +382,7 @@ extension Event.HumanReadableOutputRecorder {
       } else if issues.warningIssueCount > 0 {
         [
           Message(
-           symbol: .warning(warningIssueCount: issues.warningIssueCount),
+           symbol: .warning,
            stringValue: "\(_capitalizedTitle(for: test)) \(testName) passed after \(duration)\(issues.description)."
          )
        ]
@@ -431,7 +431,7 @@ extension Event.HumanReadableOutputRecorder {
       } else {
         switch issue.severity {
         case .warning:
-          symbol = .warning(warningIssueCount: 1)
+          symbol = .warning
           introducer = "a warning"
         case .error:
           symbol = .fail
@@ -538,7 +538,7 @@ extension Event.HumanReadableOutputRecorder {
       } else if issues.warningIssueCount > 0 {
         [
           Message(
-            symbol: .warning(warningIssueCount: issues.warningIssueCount),
+            symbol: .warning,
             stringValue: "Test run with \(testCount.counting("test")) passed after \(duration)\(issues.description)."
           )
         ]
diff --git a/Sources/Testing/Events/Recorder/Event.Symbol.swift b/Sources/Testing/Events/Recorder/Event.Symbol.swift
index d956c3faa..40bb05d40 100644
--- a/Sources/Testing/Events/Recorder/Event.Symbol.swift
+++ b/Sources/Testing/Events/Recorder/Event.Symbol.swift
@@ -34,11 +34,7 @@ extension Event {
 
     /// A warning or caution symbol to use when the developer should be aware of
     /// some condition.
-    ///
-    /// - Parameters:
-    ///   - warningIssueCount: The number of issues with warning severity
-    ///     recorded for the test. The default value is `0`.
-    case warning(warningIssueCount: Int = 0)
+    case warning
 
     /// The symbol to use when presenting details about an event to the user.
     case details

From ca838a351424d6eb7c9ee0159da0d1ac7f851259 Mon Sep 17 00:00:00 2001
From: Stuart Montgomery <smontgomery@apple.com>
Date: Tue, 28 Jan 2025 11:10:23 -0600
Subject: [PATCH 07/32] Simplify issue count tracking with a dictionary

---
 .../Event.HumanReadableOutputRecorder.swift   | 19 ++++++-------------
 1 file changed, 6 insertions(+), 13 deletions(-)

diff --git a/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift b/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift
index e2fcaeafb..aac629da8 100644
--- a/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift
+++ b/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift
@@ -56,11 +56,9 @@ extension Event {
         /// The instant at which the test started.
         var startInstant: Test.Clock.Instant
 
-        /// The number of issues with error severity recorded for the test.
-        var errorIssueCount = 0
-
-        /// The number of issues with warning severity recorded for the test.
-        var warningIssueCount = 0
+        /// The number of issues recorded for the test, grouped by their
+        /// level of severity.
+        var issueCount: [Issue.Severity: Int] = [:]
 
         /// The number of known issues recorded for the test.
         var knownIssueCount = 0
@@ -121,8 +119,8 @@ extension Event.HumanReadableOutputRecorder {
     guard let graph else {
       return (0, 0, 0, 0, "")
     }
-    let errorIssueCount = graph.compactMap(\.value?.errorIssueCount).reduce(into: 0, +=)
-    let warningIssueCount = graph.compactMap(\.value?.warningIssueCount).reduce(into: 0, +=)
+    let errorIssueCount = graph.compactMap { $0.value?.issueCount[.error] }.reduce(into: 0, +=)
+    let warningIssueCount = graph.compactMap { $0.value?.issueCount[.warning] }.reduce(into: 0, +=)
     let knownIssueCount = graph.compactMap(\.value?.knownIssueCount).reduce(into: 0, +=)
     let totalIssueCount = errorIssueCount + warningIssueCount + knownIssueCount
 
@@ -279,12 +277,7 @@ extension Event.HumanReadableOutputRecorder {
         if issue.isKnown {
           testData.knownIssueCount += 1
         } else {
-          switch issue.severity {
-          case .warning:
-            testData.warningIssueCount += 1
-          case .error:
-            testData.errorIssueCount += 1
-          }
+          testData.issueCount[issue.severity, default: 0] += 1
         }
         context.testData[id] = testData
 

From 04f115f74f371cde9646035bf6529002001f202a Mon Sep 17 00:00:00 2001
From: Stuart Montgomery <smontgomery@apple.com>
Date: Tue, 28 Jan 2025 12:21:18 -0600
Subject: [PATCH 08/32] Simplify compactMap with key path

---
 .../Events/Recorder/Event.HumanReadableOutputRecorder.swift   | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift b/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift
index aac629da8..49335519f 100644
--- a/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift
+++ b/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift
@@ -119,8 +119,8 @@ extension Event.HumanReadableOutputRecorder {
     guard let graph else {
       return (0, 0, 0, 0, "")
     }
-    let errorIssueCount = graph.compactMap { $0.value?.issueCount[.error] }.reduce(into: 0, +=)
-    let warningIssueCount = graph.compactMap { $0.value?.issueCount[.warning] }.reduce(into: 0, +=)
+    let errorIssueCount = graph.compactMap(\.value?.issueCount[.error]).reduce(into: 0, +=)
+    let warningIssueCount = graph.compactMap(\.value?.issueCount[.warning]).reduce(into: 0, +=)
     let knownIssueCount = graph.compactMap(\.value?.knownIssueCount).reduce(into: 0, +=)
     let totalIssueCount = errorIssueCount + warningIssueCount + knownIssueCount
 

From a51b3856fdc8aafb9c2d546b416009e133529990 Mon Sep 17 00:00:00 2001
From: Stuart Montgomery <smontgomery@apple.com>
Date: Tue, 28 Jan 2025 12:21:41 -0600
Subject: [PATCH 09/32] Replace "a warning issue" with "a warning"

---
 .../Recorder/Event.HumanReadableOutputRecorder.swift | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift b/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift
index 49335519f..d2fa235f0 100644
--- a/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift
+++ b/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift
@@ -417,18 +417,18 @@ extension Event.HumanReadableOutputRecorder {
         ""
       }
       let symbol: Event.Symbol
-      let introducer: String
+      let subject: String
       if issue.isKnown {
         symbol = .pass(knownIssueCount: 1)
-        introducer = "a known"
+        subject = "a known issue"
       } else {
         switch issue.severity {
         case .warning:
           symbol = .warning
-          introducer = "a warning"
+          subject = "a warning"
         case .error:
           symbol = .fail
-          introducer = "an"
+          subject = "an issue"
         }
       }
 
@@ -458,13 +458,13 @@ extension Event.HumanReadableOutputRecorder {
       let primaryMessage: Message = if parameterCount == 0 {
         Message(
           symbol: symbol,
-          stringValue: "\(_capitalizedTitle(for: test)) \(testName) recorded \(introducer) issue\(atSourceLocation): \(issue.kind)",
+          stringValue: "\(_capitalizedTitle(for: test)) \(testName) recorded \(subject) \(atSourceLocation): \(issue.kind)",
           conciseStringValue: String(describing: issue.kind)
         )
       } else {
         Message(
           symbol: symbol,
-          stringValue: "\(_capitalizedTitle(for: test)) \(testName) recorded \(introducer) issue with \(parameterCount.counting("argument")) \(labeledArguments)\(atSourceLocation): \(issue.kind)",
+          stringValue: "\(_capitalizedTitle(for: test)) \(testName) recorded \(subject) with \(parameterCount.counting("argument")) \(labeledArguments)\(atSourceLocation): \(issue.kind)",
           conciseStringValue: String(describing: issue.kind)
         )
       }

From fba703fa48d0f1d61db8130dff3aa2dd4d198544 Mon Sep 17 00:00:00 2001
From: Stuart Montgomery <smontgomery@apple.com>
Date: Wed, 29 Jan 2025 17:23:22 -0600
Subject: [PATCH 10/32] Introduce new Configuration SPI controlling whether
 warning issues should be delivered, consolidating some similar functionality
 with an existing SPI. Address the ABI compatibility problem by defaulting all
 existing entry point versions to disable this feature, but default it to
 enabled so that the eventual v1 will have it enabled by default

---
 .../ABI/EntryPoints/ABIEntryPoint.swift       |  6 +--
 .../Testing/ABI/EntryPoints/EntryPoint.swift  |  9 ++++
 Sources/Testing/Events/Event.swift            | 25 +++++++++--
 Sources/Testing/Running/Configuration.swift   | 45 ++++++++++++++++---
 4 files changed, 71 insertions(+), 14 deletions(-)

diff --git a/Sources/Testing/ABI/EntryPoints/ABIEntryPoint.swift b/Sources/Testing/ABI/EntryPoints/ABIEntryPoint.swift
index cc150740e..143f7b549 100644
--- a/Sources/Testing/ABI/EntryPoints/ABIEntryPoint.swift
+++ b/Sources/Testing/ABI/EntryPoints/ABIEntryPoint.swift
@@ -47,7 +47,7 @@ extension ABIv0 {
   /// callback.
   public static var entryPoint: EntryPoint {
     return { configurationJSON, recordHandler in
-      try await Testing.entryPoint(
+      try await _entryPoint(
         configurationJSON: configurationJSON,
         recordHandler: recordHandler
       ) == EXIT_SUCCESS
@@ -87,7 +87,7 @@ typealias ABIEntryPoint_v0 = @Sendable (
 @usableFromInline func copyABIEntryPoint_v0() -> UnsafeMutableRawPointer {
   let result = UnsafeMutablePointer<ABIEntryPoint_v0>.allocate(capacity: 1)
   result.initialize { configurationJSON, recordHandler in
-    try await entryPoint(
+    try await _entryPoint(
       configurationJSON: configurationJSON,
       eventStreamVersionIfNil: -1,
       recordHandler: recordHandler
@@ -104,7 +104,7 @@ typealias ABIEntryPoint_v0 = @Sendable (
 ///
 /// This function will be removed (with its logic incorporated into
 /// ``ABIv0/entryPoint-swift.type.property``) in a future update.
-private func entryPoint(
+private func _entryPoint(
   configurationJSON: UnsafeRawBufferPointer?,
   eventStreamVersionIfNil: Int? = nil,
   recordHandler: @escaping @Sendable (_ recordJSON: UnsafeRawBufferPointer) -> Void
diff --git a/Sources/Testing/ABI/EntryPoints/EntryPoint.swift b/Sources/Testing/ABI/EntryPoints/EntryPoint.swift
index 254311968..700e50ffa 100644
--- a/Sources/Testing/ABI/EntryPoints/EntryPoint.swift
+++ b/Sources/Testing/ABI/EntryPoints/EntryPoint.swift
@@ -547,6 +547,15 @@ public func configurationForEntryPoint(from args: __CommandLineArguments_v0) thr
   configuration.exitTestHandler = ExitTest.handlerForEntryPoint()
 #endif
 
+  switch args.eventStreamVersion {
+  case .some(...0):
+    // If the event stream version was specified explicitly to a value < 1,
+    // disable delivery of warning issue events to maintain legacy behavior.
+    configuration.eventHandlingOptions.isWarningIssueEventDeliveryEnabled = false
+  default:
+    break
+  }
+
   return configuration
 }
 
diff --git a/Sources/Testing/Events/Event.swift b/Sources/Testing/Events/Event.swift
index 60e564d5a..dc5468465 100644
--- a/Sources/Testing/Events/Event.swift
+++ b/Sources/Testing/Events/Event.swift
@@ -290,10 +290,7 @@ extension Event {
     if let configuration = configuration ?? Configuration.current {
       // The caller specified a configuration, or the current task has an
       // associated configuration. Post to either configuration's event handler.
-      switch kind {
-      case .expectationChecked where !configuration.deliverExpectationCheckedEvents:
-        break
-      default:
+      if configuration.eventHandlingOptions.shouldHandleEvent(self) {
         configuration.handleEvent(self, in: context)
       }
     } else {
@@ -306,6 +303,26 @@ extension Event {
   }
 }
 
+extension Configuration.EventHandlingOptions {
+  /// Determine whether the specified event should be handled according to the
+  /// options in this instance.
+  ///
+  /// - Parameters:
+  ///   - event: The event to consider handling.
+  ///
+  /// - Returns: Whether or not the event should be handled or suppressed.
+  fileprivate func shouldHandleEvent(_ event: borrowing Event) -> Bool {
+    switch event.kind {
+    case let .issueRecorded(issue):
+      issue.severity > .warning || isWarningIssueEventDeliveryEnabled
+    case .expectationChecked:
+      isExpectationCheckedEventDeliveryEnabled
+    default:
+      true
+    }
+  }
+}
+
 #if !SWT_NO_SNAPSHOT_TYPES
 // MARK: - Snapshotting
 
diff --git a/Sources/Testing/Running/Configuration.swift b/Sources/Testing/Running/Configuration.swift
index f4ae59813..fa2d868fc 100644
--- a/Sources/Testing/Running/Configuration.swift
+++ b/Sources/Testing/Running/Configuration.swift
@@ -178,14 +178,35 @@ public struct Configuration: Sendable {
 
   // MARK: - Event handling
 
-  /// Whether or not events of the kind
-  /// ``Event/Kind-swift.enum/expectationChecked(_:)`` should be delivered to
-  /// this configuration's ``eventHandler`` closure.
+  /// A type describing options to use when delivering events to this
+  /// configuration's event handler
+  public struct EventHandlingOptions: Sendable {
+    /// Whether or not events of the kind ``Event/Kind-swift.enum/issueRecorded(_:)``
+    /// containing issues with warning (or lower) severity should be delivered
+    /// to the event handler of the configuration these options are applied to.
+    ///
+    /// By default, events matching this criteria are delivered to event
+    /// handlers unless the entry point specifies an event stream version which
+    /// predates the introduction of warning issues, in which case this is
+    /// disabled to maintain legacy behavior.
+    public var isWarningIssueEventDeliveryEnabled: Bool = true
+
+    /// Whether or not events of the kind
+    /// ``Event/Kind-swift.enum/expectationChecked(_:)`` should be delivered to
+    /// the event handler of the configuration these options are applied to.
+    ///
+    /// By default, events of this kind are not delivered to event handlers
+    /// because they occur frequently in a typical test run and can generate
+    /// significant back-pressure on the event handler.
+    public var isExpectationCheckedEventDeliveryEnabled: Bool = false
+  }
+
+  /// The options to use when delivering events to this configuration's event
+  /// handler.
   ///
-  /// By default, events of this kind are not delivered to event handlers
-  /// because they occur frequently in a typical test run and can generate
-  /// significant backpressure on the event handler.
-  public var deliverExpectationCheckedEvents: Bool = false
+  /// The default value of this property is an instance of ``EventHandlingOptions-swift.struct``
+  /// with its properties initialized to their default values.
+  public var eventHandlingOptions: EventHandlingOptions = .init()
 
   /// The event handler to which events should be passed when they occur.
   public var eventHandler: Event.Handler = { _, _ in }
@@ -325,4 +346,14 @@ extension Configuration {
     }
   }
 #endif
+
+  @available(*, deprecated, message: "Set eventHandlingOptions.isExpectationCheckedEventDeliveryEnabled instead.")
+  public var deliverExpectationCheckedEvents: Bool {
+    get {
+      eventHandlingOptions.isExpectationCheckedEventDeliveryEnabled
+    }
+    set {
+      eventHandlingOptions.isExpectationCheckedEventDeliveryEnabled = newValue
+    }
+  }
 }

From cefc62de98a2fdab4074507f1539c1b1212e1cab Mon Sep 17 00:00:00 2001
From: Stuart Montgomery <smontgomery@apple.com>
Date: Wed, 29 Jan 2025 21:29:02 -0600
Subject: [PATCH 11/32] Attempt to work around compiler crash

---
 .../Events/Recorder/Event.HumanReadableOutputRecorder.swift    | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift b/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift
index d2fa235f0..ef784a195 100644
--- a/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift
+++ b/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift
@@ -277,7 +277,8 @@ extension Event.HumanReadableOutputRecorder {
         if issue.isKnown {
           testData.knownIssueCount += 1
         } else {
-          testData.issueCount[issue.severity, default: 0] += 1
+          let issueCount = testData.issueCount[issue.severity] ?? 0
+          testData.issueCount[issue.severity] = issueCount + 1
         }
         context.testData[id] = testData
 

From f224697ddfa9fdb0f0c60e6dc17e6b3521bf304c Mon Sep 17 00:00:00 2001
From: Stuart Montgomery <smontgomery@apple.com>
Date: Thu, 30 Jan 2025 11:15:08 -0600
Subject: [PATCH 12/32] PR feedback

---
 Documentation/ABI/JSON.md                      | 16 ++++++----------
 .../Testing/ABI/EntryPoints/EntryPoint.swift   |  2 +-
 Sources/Testing/Events/Event.swift             |  4 ++--
 Sources/Testing/Running/Configuration.swift    | 18 +++++++++---------
 4 files changed, 18 insertions(+), 22 deletions(-)

diff --git a/Documentation/ABI/JSON.md b/Documentation/ABI/JSON.md
index 0a97c9e68..2fcf4b268 100644
--- a/Documentation/ABI/JSON.md
+++ b/Documentation/ABI/JSON.md
@@ -197,20 +197,10 @@ sufficient information to display the event in a human-readable format.
   "runEnded" ; additional event kinds may be added in the future
 
 <issue> ::= {
-<!--
-  TODO: Publicize the severity field.
-  "severity" ::= <issue-severity>, ; the severity of the issue
--->
   "isKnown": <bool>, ; is this a known issue or not?
   ["sourceLocation": <source-location>,] ; where the issue occurred, if known
 }
 
-<!--
-  TODO: Publicize the severity field.
-<issue-severity> ::= "warning" | "error" ; additional severity levels may be
-                                         ; added in the future
--->
-
 <message> ::= {
   "symbol": <message-symbol>,
   "text": <string>, ; the human-readable text of this message
@@ -220,6 +210,12 @@ sufficient information to display the event in a human-readable format.
   "fail" | "difference" | "warning" | "details"
 ```
 
+<!--
+  TODO: Publicize issue severity.
+<issue-severity> ::= "warning" | "error" ; additional severity levels may be
+                                         ; added in the future
+-->
+
 <!--
   ["testID": <test-id>,
     ["testCase": <test-case>]]
diff --git a/Sources/Testing/ABI/EntryPoints/EntryPoint.swift b/Sources/Testing/ABI/EntryPoints/EntryPoint.swift
index 700e50ffa..dd83bb01c 100644
--- a/Sources/Testing/ABI/EntryPoints/EntryPoint.swift
+++ b/Sources/Testing/ABI/EntryPoints/EntryPoint.swift
@@ -551,7 +551,7 @@ public func configurationForEntryPoint(from args: __CommandLineArguments_v0) thr
   case .some(...0):
     // If the event stream version was specified explicitly to a value < 1,
     // disable delivery of warning issue events to maintain legacy behavior.
-    configuration.eventHandlingOptions.isWarningIssueEventDeliveryEnabled = false
+    configuration.eventHandlingOptions.isWarningIssueRecordedEventEnabled = false
   default:
     break
   }
diff --git a/Sources/Testing/Events/Event.swift b/Sources/Testing/Events/Event.swift
index dc5468465..507549604 100644
--- a/Sources/Testing/Events/Event.swift
+++ b/Sources/Testing/Events/Event.swift
@@ -314,9 +314,9 @@ extension Configuration.EventHandlingOptions {
   fileprivate func shouldHandleEvent(_ event: borrowing Event) -> Bool {
     switch event.kind {
     case let .issueRecorded(issue):
-      issue.severity > .warning || isWarningIssueEventDeliveryEnabled
+      issue.severity > .warning || isWarningIssueRecordedEventEnabled
     case .expectationChecked:
-      isExpectationCheckedEventDeliveryEnabled
+      isExpectationCheckedEventEnabled
     default:
       true
     }
diff --git a/Sources/Testing/Running/Configuration.swift b/Sources/Testing/Running/Configuration.swift
index fa2d868fc..868cb16a2 100644
--- a/Sources/Testing/Running/Configuration.swift
+++ b/Sources/Testing/Running/Configuration.swift
@@ -185,11 +185,11 @@ public struct Configuration: Sendable {
     /// containing issues with warning (or lower) severity should be delivered
     /// to the event handler of the configuration these options are applied to.
     ///
-    /// By default, events matching this criteria are delivered to event
-    /// handlers unless the entry point specifies an event stream version which
-    /// predates the introduction of warning issues, in which case this is
-    /// disabled to maintain legacy behavior.
-    public var isWarningIssueEventDeliveryEnabled: Bool = true
+    /// By default, events matching this criteria are not delivered to event
+    /// handlers since this is an experimental feature.
+    ///
+    /// - Warning: Warning issues are not yet an approved feature.
+    public var isWarningIssueRecordedEventEnabled: Bool = false
 
     /// Whether or not events of the kind
     /// ``Event/Kind-swift.enum/expectationChecked(_:)`` should be delivered to
@@ -198,7 +198,7 @@ public struct Configuration: Sendable {
     /// By default, events of this kind are not delivered to event handlers
     /// because they occur frequently in a typical test run and can generate
     /// significant back-pressure on the event handler.
-    public var isExpectationCheckedEventDeliveryEnabled: Bool = false
+    public var isExpectationCheckedEventEnabled: Bool = false
   }
 
   /// The options to use when delivering events to this configuration's event
@@ -347,13 +347,13 @@ extension Configuration {
   }
 #endif
 
-  @available(*, deprecated, message: "Set eventHandlingOptions.isExpectationCheckedEventDeliveryEnabled instead.")
+  @available(*, deprecated, message: "Set eventHandlingOptions.isExpectationCheckedEventEnabled instead.")
   public var deliverExpectationCheckedEvents: Bool {
     get {
-      eventHandlingOptions.isExpectationCheckedEventDeliveryEnabled
+      eventHandlingOptions.isExpectationCheckedEventEnabled
     }
     set {
-      eventHandlingOptions.isExpectationCheckedEventDeliveryEnabled = newValue
+      eventHandlingOptions.isExpectationCheckedEventEnabled = newValue
     }
   }
 }

From e9c84c306a5583ffc4899a47fc331c091049b243 Mon Sep 17 00:00:00 2001
From: Stuart Montgomery <smontgomery@apple.com>
Date: Mon, 3 Feb 2025 21:15:00 -0600
Subject: [PATCH 13/32] Fix severity property in Issue not being assigned in
 initializer, and don't give the property itself a default value

---
 Sources/Testing/Issues/Issue.swift | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/Sources/Testing/Issues/Issue.swift b/Sources/Testing/Issues/Issue.swift
index e161adfcc..738e94b27 100644
--- a/Sources/Testing/Issues/Issue.swift
+++ b/Sources/Testing/Issues/Issue.swift
@@ -102,10 +102,8 @@ public struct Issue: Sendable {
   }
 
   /// The severity of this issue.
-  ///
-  /// The default value of this property is ``Severity-swift.enum/error``.
   @_spi(Experimental)
-  public var severity: Severity = .error
+  public var severity: Severity
 
   /// Any comments provided by the developer and associated with this issue.
   ///
@@ -138,6 +136,7 @@ public struct Issue: Sendable {
     sourceContext: SourceContext
   ) {
     self.kind = kind
+    self.severity = severity
     self.comments = comments
     self.sourceContext = sourceContext
   }

From 50a61438c7cfee79af0351f634429e6a7322aa59 Mon Sep 17 00:00:00 2001
From: Stuart Montgomery <smontgomery@apple.com>
Date: Mon, 3 Feb 2025 21:26:43 -0600
Subject: [PATCH 14/32] Improve Issue's Custom(Debug)StringConvertible
 implementations

---
 Sources/Testing/Issues/Issue.swift  | 52 ++++++++++++++++-------------
 Tests/TestingTests/IssueTests.swift |  6 ++--
 2 files changed, 31 insertions(+), 27 deletions(-)

diff --git a/Sources/Testing/Issues/Issue.swift b/Sources/Testing/Issues/Issue.swift
index 738e94b27..bcd7b3c90 100644
--- a/Sources/Testing/Issues/Issue.swift
+++ b/Sources/Testing/Issues/Issue.swift
@@ -190,23 +190,25 @@ extension Issue.Severity: Comparable {}
 
 extension Issue: CustomStringConvertible, CustomDebugStringConvertible {
   public var description: String {
-    if comments.isEmpty {
-      return String(describing: kind)
+    let joinedComments = if comments.isEmpty {
+      ""
+    } else {
+      ": " + comments.lazy
+        .map(\.rawValue)
+        .joined(separator: "\n")
     }
-    let joinedComments = comments.lazy
-      .map(\.rawValue)
-      .joined(separator: "\n")
-    return "\(severity): \(kind): \(joinedComments)"
+    return "\(kind) (\(severity))\(joinedComments)"
   }
 
   public var debugDescription: String {
-    if comments.isEmpty {
-      return "\(kind)\(sourceLocation.map { " at \($0)" } ?? "")"
+    let joinedComments = if comments.isEmpty {
+      ""
+    } else {
+      ": " + comments.lazy
+        .map(\.rawValue)
+        .joined(separator: "\n")
     }
-    let joinedComments: String = comments.lazy
-      .map(\.rawValue)
-      .joined(separator: "\n")
-    return "\(severity): \(kind)\(sourceLocation.map { " at \($0)" } ?? ""): \(joinedComments)"
+    return "\(kind)\(sourceLocation.map { " at \($0)" } ?? "") (\(severity))\(joinedComments)"
   }
 }
 
@@ -528,23 +530,25 @@ extension Issue.Kind {
 
 extension Issue.Snapshot: CustomStringConvertible, CustomDebugStringConvertible {
   public var description: String {
-    if comments.isEmpty {
-      return String(describing: kind)
+    let joinedComments = if comments.isEmpty {
+      ""
+    } else {
+      ": " + comments.lazy
+        .map(\.rawValue)
+        .joined(separator: "\n")
     }
-    let joinedComments = comments.lazy
-      .map(\.rawValue)
-      .joined(separator: "\n")
-    return "\(severity): \(kind): \(joinedComments)"
+    return "\(kind) (\(severity))\(joinedComments)"
   }
 
   public var debugDescription: String {
-    if comments.isEmpty {
-      return "\(kind)\(sourceLocation.map { " at \($0)" } ?? "")"
+    let joinedComments = if comments.isEmpty {
+      ""
+    } else {
+      ": " + comments.lazy
+        .map(\.rawValue)
+        .joined(separator: "\n")
     }
-    let joinedComments: String = comments.lazy
-      .map(\.rawValue)
-      .joined(separator: "\n")
-    return "\(severity): \(kind)\(sourceLocation.map { " at \($0)" } ?? ""): \(joinedComments)"
+    return "\(kind)\(sourceLocation.map { " at \($0)" } ?? "") (\(severity))\(joinedComments)"
   }
 }
 
diff --git a/Tests/TestingTests/IssueTests.swift b/Tests/TestingTests/IssueTests.swift
index cdcf9f3b1..7402d9c4e 100644
--- a/Tests/TestingTests/IssueTests.swift
+++ b/Tests/TestingTests/IssueTests.swift
@@ -1124,12 +1124,12 @@ final class IssueTests: XCTestCase {
     do {
       let sourceLocation = SourceLocation.init(fileID: "FakeModule/FakeFile.swift", filePath: "", line: 9999, column: 1)
       let issue = Issue(kind: .system, comments: ["Some issue"], sourceContext: SourceContext(sourceLocation: sourceLocation))
-      XCTAssertEqual(issue.description, "error: A system failure occurred: Some issue")
-      XCTAssertEqual(issue.debugDescription, "error: A system failure occurred at FakeFile.swift:9999:1: Some issue")
+      XCTAssertEqual(issue.description, "A system failure occurred (error): Some issue")
+      XCTAssertEqual(issue.debugDescription, "A system failure occurred at FakeFile.swift:9999:1 (error): Some issue")
     }
     do {
       let issue = Issue(kind: .system, comments: ["Some issue"], sourceContext: SourceContext(sourceLocation: nil))
-      XCTAssertEqual(issue.debugDescription, "error: A system failure occurred: Some issue")
+      XCTAssertEqual(issue.debugDescription, "A system failure occurred (error): Some issue")
     }
   }
 

From b8f81cf1216a0063b79e3aafd373a5b56b826e55 Mon Sep 17 00:00:00 2001
From: Stuart Montgomery <smontgomery@apple.com>
Date: Mon, 3 Feb 2025 21:27:27 -0600
Subject: [PATCH 15/32] Drive-by fix for private function underscore prefix

---
 Tests/TestingTests/ABIEntryPointTests.swift | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/Tests/TestingTests/ABIEntryPointTests.swift b/Tests/TestingTests/ABIEntryPointTests.swift
index 86ede749e..f0bebf904 100644
--- a/Tests/TestingTests/ABIEntryPointTests.swift
+++ b/Tests/TestingTests/ABIEntryPointTests.swift
@@ -54,7 +54,7 @@ struct ABIEntryPointTests {
   ) async throws -> CInt {
 #if !SWT_NO_DYNAMIC_LINKING
     // Get the ABI entry point by dynamically looking it up at runtime.
-    let copyABIEntryPoint_v0 = try withTestingLibraryImageAddress { testingLibrary in
+    let copyABIEntryPoint_v0 = try _withTestingLibraryImageAddress { testingLibrary in
       try #require(
         symbol(in: testingLibrary, named: "swt_copyABIEntryPoint_v0").map {
           unsafeBitCast($0, to: (@convention(c) () -> UnsafeMutableRawPointer).self)
@@ -137,7 +137,7 @@ struct ABIEntryPointTests {
     // NOTE: The standard Linux linker does not allow exporting symbols from
     // executables, so dlsym() does not let us find this function on that
     // platform when built as an executable rather than a dynamic library.
-    let abiv0_getEntryPoint = try withTestingLibraryImageAddress { testingLibrary in
+    let abiv0_getEntryPoint = try _withTestingLibraryImageAddress { testingLibrary in
       try #require(
         symbol(in: testingLibrary, named: "swt_abiv0_getEntryPoint").map {
           unsafeBitCast($0, to: (@convention(c) () -> UnsafeRawPointer).self)
@@ -171,7 +171,7 @@ struct ABIEntryPointTests {
 }
 
 #if !SWT_NO_DYNAMIC_LINKING
-private func withTestingLibraryImageAddress<R>(_ body: (ImageAddress?) throws -> R) throws -> R {
+private func _withTestingLibraryImageAddress<R>(_ body: (ImageAddress?) throws -> R) throws -> R {
   let addressInTestingLibrary = unsafeBitCast(ABIv0.entryPoint, to: UnsafeRawPointer.self)
 
   var testingLibraryAddress: ImageAddress?

From b74187c942e8b4b3842cb2ab504fcd5f6ff5c3b3 Mon Sep 17 00:00:00 2001
From: Stuart Montgomery <smontgomery@apple.com>
Date: Mon, 3 Feb 2025 21:39:12 -0600
Subject: [PATCH 16/32] Add tests of the v0 entry point, with and without
 warning issues enabled. Toggle this via a new property on
 __CommandLineArguments_v0

---
 .../Testing/ABI/EntryPoints/EntryPoint.swift  | 28 +++++++---
 Tests/TestingTests/ABIEntryPointTests.swift   | 51 +++++++++++++++++++
 2 files changed, 72 insertions(+), 7 deletions(-)

diff --git a/Sources/Testing/ABI/EntryPoints/EntryPoint.swift b/Sources/Testing/ABI/EntryPoints/EntryPoint.swift
index dd83bb01c..2b881b10f 100644
--- a/Sources/Testing/ABI/EntryPoints/EntryPoint.swift
+++ b/Sources/Testing/ABI/EntryPoints/EntryPoint.swift
@@ -278,6 +278,13 @@ public struct __CommandLineArguments_v0: Sendable {
 
   /// The value of the `--experimental-attachments-path` argument.
   public var experimentalAttachmentsPath: String?
+
+  /// The value(s) of the `--enable-experimental-feature` argument(s),
+  /// indicating the name(s) of experimental features to enable.
+  ///
+  /// The value of this property is not yet populated by parsing command-line
+  /// arguments, but may be in the future.
+  public var experimentalFeatures: [String]?
 }
 
 extension __CommandLineArguments_v0: Codable {
@@ -299,6 +306,7 @@ extension __CommandLineArguments_v0: Codable {
     case repetitions
     case repeatUntil
     case experimentalAttachmentsPath
+    case experimentalFeatures
   }
 }
 
@@ -547,13 +555,19 @@ public func configurationForEntryPoint(from args: __CommandLineArguments_v0) thr
   configuration.exitTestHandler = ExitTest.handlerForEntryPoint()
 #endif
 
-  switch args.eventStreamVersion {
-  case .some(...0):
-    // If the event stream version was specified explicitly to a value < 1,
-    // disable delivery of warning issue events to maintain legacy behavior.
-    configuration.eventHandlingOptions.isWarningIssueRecordedEventEnabled = false
-  default:
-    break
+  configuration.eventHandlingOptions.isWarningIssueRecordedEventEnabled = if (args.experimentalFeatures ?? []).contains("WarningIssues") {
+    true
+  } else {
+    switch args.eventStreamVersion {
+    case .some(...0):
+      // If the event stream version was explicitly specified to a value < 1,
+      // disable the warning issue event to maintain legacy behavior.
+      false
+    default:
+      // Otherwise the requested event stream version is ≥ 1, so don't change
+      // the warning issue event setting.
+      configuration.eventHandlingOptions.isWarningIssueRecordedEventEnabled
+    }
   }
 
   return configuration
diff --git a/Tests/TestingTests/ABIEntryPointTests.swift b/Tests/TestingTests/ABIEntryPointTests.swift
index f0bebf904..d244601fa 100644
--- a/Tests/TestingTests/ABIEntryPointTests.swift
+++ b/Tests/TestingTests/ABIEntryPointTests.swift
@@ -127,6 +127,50 @@ struct ABIEntryPointTests {
     }
   }
 
+  @Test("v0 entry point with WarningIssues feature enabled exits with success if all issues have severity < .error")
+  func v0_warningIssues() async throws {
+    var arguments = __CommandLineArguments_v0()
+    arguments.filter = ["_recordWarningIssue"]
+    arguments.eventStreamVersion = 0
+    arguments.verbosity = .min
+
+    let result = try await confirmation("Test matched", expectedCount: 1) { testMatched in
+      try await _invokeEntryPointV0(passing: arguments) { recordJSON in
+        let record = try! JSON.decode(ABIv0.Record.self, from: recordJSON)
+        if case let .event(event) = record.kind {
+          if case .testStarted = event.kind {
+            testMatched()
+          } else if case .issueRecorded = event.kind, let issue = event.issue {
+            Issue.record("Unexpected issue \(issue) was recorded to the event handler of a v0 entry point.")
+          }
+        }
+      }
+    }
+    #expect(result)
+  }
+
+  @Test("v0 entry point with WarningIssues feature enabled propagates warning issues and exits with success if all issues have severity < .error")
+  func v0_warningIssuesEnabled() async throws {
+    var arguments = __CommandLineArguments_v0()
+    arguments.filter = ["_recordWarningIssue"]
+    arguments.eventStreamVersion = 0
+    arguments.experimentalFeatures = ["WarningIssues"]
+    arguments.verbosity = .min
+
+    let result = try await confirmation("Warning issue recorded", expectedCount: 1) { issueRecorded in
+      try await _invokeEntryPointV0(passing: arguments) { recordJSON in
+        let record = try! JSON.decode(ABIv0.Record.self, from: recordJSON)
+        if case let .event(event) = record.kind {
+          if case .issueRecorded = event.kind, let issue = event.issue {
+            #expect(issue._severity == .warning)
+            issueRecorded()
+          }
+        }
+      }
+    }
+    #expect(result)
+  }
+
   private func _invokeEntryPointV0(
     passing arguments: __CommandLineArguments_v0,
     recordHandler: @escaping @Sendable (_ recordJSON: UnsafeRawBufferPointer) -> Void = { _ in }
@@ -202,3 +246,10 @@ private func _withTestingLibraryImageAddress<R>(_ body: (ImageAddress?) throws -
 }
 #endif
 #endif
+
+// MARK: - Fixtures
+
+@Test private func _recordWarningIssue() {
+  // Intentionally _only_ record issues with warning (or lower) severity.
+  Issue(kind: .unconditional, severity: .warning, comments: [], sourceContext: .init()).record()
+}

From 02996d76aeedd421399af32d28c0e884b9db2a43 Mon Sep 17 00:00:00 2001
From: Stuart Montgomery <smontgomery@apple.com>
Date: Mon, 3 Feb 2025 21:40:41 -0600
Subject: [PATCH 17/32] Make the fixture @Test function added in the previous
 commit `.hidden`, and allow selecting it via another new property on
 __CommandLineArguments_v0. Add a test specifically for that functionality in
 isolation

---
 .../Testing/ABI/EntryPoints/EntryPoint.swift  | 11 +++++++++
 Tests/TestingTests/ABIEntryPointTests.swift   | 24 ++++++++++++++++++-
 2 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/Sources/Testing/ABI/EntryPoints/EntryPoint.swift b/Sources/Testing/ABI/EntryPoints/EntryPoint.swift
index 2b881b10f..b12c0d8cf 100644
--- a/Sources/Testing/ABI/EntryPoints/EntryPoint.swift
+++ b/Sources/Testing/ABI/EntryPoints/EntryPoint.swift
@@ -270,6 +270,13 @@ public struct __CommandLineArguments_v0: Sendable {
   /// The value(s) of the `--skip` argument.
   public var skip: [String]?
 
+  /// Whether or not to include tests with the `.hidden` trait when constructing
+  /// a test filter based on these arguments.
+  ///
+  /// This property is intended for use in testing the testing library itself.
+  /// It is not parsed as a command-line argument.
+  public var includeHiddenTests: Bool?
+
   /// The value of the `--repetitions` argument.
   public var repetitions: Int?
 
@@ -303,6 +310,7 @@ extension __CommandLineArguments_v0: Codable {
     case eventStreamVersion
     case filter
     case skip
+    case includeHiddenTests
     case repetitions
     case repeatUntil
     case experimentalAttachmentsPath
@@ -525,6 +533,9 @@ public func configurationForEntryPoint(from args: __CommandLineArguments_v0) thr
   filters.append(try testFilter(forRegularExpressions: args.skip, label: "--skip", membership: .excluding))
 
   configuration.testFilter = filters.reduce(.unfiltered) { $0.combining(with: $1) }
+  if args.includeHiddenTests == true {
+    configuration.testFilter.includeHiddenTests = true
+  }
 
   // Set up the iteration policy for the test run.
   var repetitionPolicy: Configuration.RepetitionPolicy = .once
diff --git a/Tests/TestingTests/ABIEntryPointTests.swift b/Tests/TestingTests/ABIEntryPointTests.swift
index d244601fa..95f75c215 100644
--- a/Tests/TestingTests/ABIEntryPointTests.swift
+++ b/Tests/TestingTests/ABIEntryPointTests.swift
@@ -127,10 +127,29 @@ struct ABIEntryPointTests {
     }
   }
 
+  @Test("v0 entry point filter with filtering of hidden tests enabled")
+  func v0_hiddenTests() async throws {
+    var arguments = __CommandLineArguments_v0()
+    arguments.filter = ["_someHiddenTest"]
+    arguments.includeHiddenTests = true
+    arguments.eventStreamVersion = 0
+    arguments.verbosity = .min
+
+    try await confirmation("Test event started", expectedCount: 1) { testMatched in
+      _ = try await _invokeEntryPointV0(passing: arguments) { recordJSON in
+        let record = try! JSON.decode(ABIv0.Record.self, from: recordJSON)
+        if case let .event(event) = record.kind, case .testStarted = event.kind {
+          testMatched()
+        }
+      }
+    }
+  }
+
   @Test("v0 entry point with WarningIssues feature enabled exits with success if all issues have severity < .error")
   func v0_warningIssues() async throws {
     var arguments = __CommandLineArguments_v0()
     arguments.filter = ["_recordWarningIssue"]
+    arguments.includeHiddenTests = true
     arguments.eventStreamVersion = 0
     arguments.verbosity = .min
 
@@ -153,6 +172,7 @@ struct ABIEntryPointTests {
   func v0_warningIssuesEnabled() async throws {
     var arguments = __CommandLineArguments_v0()
     arguments.filter = ["_recordWarningIssue"]
+    arguments.includeHiddenTests = true
     arguments.eventStreamVersion = 0
     arguments.experimentalFeatures = ["WarningIssues"]
     arguments.verbosity = .min
@@ -249,7 +269,9 @@ private func _withTestingLibraryImageAddress<R>(_ body: (ImageAddress?) throws -
 
 // MARK: - Fixtures
 
-@Test private func _recordWarningIssue() {
+@Test(.hidden) private func _someHiddenTest() {}
+
+@Test(.hidden) private func _recordWarningIssue() {
   // Intentionally _only_ record issues with warning (or lower) severity.
   Issue(kind: .unconditional, severity: .warning, comments: [], sourceContext: .init()).record()
 }

From ce1f4b85b6e3317bf251b22ba8b2a5bc574dda8b Mon Sep 17 00:00:00 2001
From: Stuart Montgomery <smontgomery@apple.com>
Date: Mon, 3 Feb 2025 22:01:30 -0600
Subject: [PATCH 18/32] Update usages of now-deprecated Configuration property

---
 Sources/Testing/Running/Runner.RuntimeState.swift | 10 ++++++----
 Tests/TestingTests/EventRecorderTests.swift       |  8 ++++----
 Tests/TestingTests/IssueTests.swift               |  2 +-
 Tests/TestingTests/Runner.RuntimeStateTests.swift |  2 +-
 Tests/TestingTests/RunnerTests.swift              |  4 ++--
 5 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/Sources/Testing/Running/Runner.RuntimeState.swift b/Sources/Testing/Running/Runner.RuntimeState.swift
index f69e13cd6..6c2764044 100644
--- a/Sources/Testing/Running/Runner.RuntimeState.swift
+++ b/Sources/Testing/Running/Runner.RuntimeState.swift
@@ -132,7 +132,7 @@ extension Configuration {
   /// - Returns: A unique number identifying `self` that can be
   ///   passed to `_removeFromAll(identifiedBy:)`` to unregister it.
   private func _addToAll() -> UInt64 {
-    if deliverExpectationCheckedEvents {
+    if eventHandlingOptions.isExpectationCheckedEventEnabled {
       Self._deliverExpectationCheckedEventsCount.increment()
     }
     return Self._all.withLock { all in
@@ -152,13 +152,14 @@ extension Configuration {
     let configuration = Self._all.withLock { all in
       all.instances.removeValue(forKey: id)
     }
-    if let configuration, configuration.deliverExpectationCheckedEvents {
+    if let configuration, configuration.eventHandlingOptions.isExpectationCheckedEventEnabled {
       Self._deliverExpectationCheckedEventsCount.decrement()
     }
   }
 
   /// An atomic counter that tracks the number of "current" configurations that
-  /// have set ``deliverExpectationCheckedEvents`` to `true`.
+  /// have set ``EventHandlingOptions/isExpectationCheckedEventEnabled`` to
+  /// `true`.
   ///
   /// On older Apple platforms, this property is not available and ``all`` is
   /// directly consulted instead (which is less efficient.)
@@ -171,7 +172,8 @@ extension Configuration {
   ///
   /// To determine if an individual instance of ``Configuration`` is listening
   /// for these events, consult the per-instance
-  /// ``Configuration/deliverExpectationCheckedEvents`` property.
+  /// ``Configuration/EventHandlingOptions/isExpectationCheckedEventEnabled``
+  /// property.
   static var deliverExpectationCheckedEvents: Bool {
     _deliverExpectationCheckedEventsCount.rawValue > 0
   }
diff --git a/Tests/TestingTests/EventRecorderTests.swift b/Tests/TestingTests/EventRecorderTests.swift
index 97619b755..821d1ce60 100644
--- a/Tests/TestingTests/EventRecorderTests.swift
+++ b/Tests/TestingTests/EventRecorderTests.swift
@@ -59,7 +59,7 @@ struct EventRecorderTests {
     }
 
     var configuration = Configuration()
-    configuration.deliverExpectationCheckedEvents = true
+    configuration.eventHandlingOptions.isExpectationCheckedEventEnabled = true
     let eventRecorder = Event.ConsoleOutputRecorder(options: options, writingUsing: stream.write)
     configuration.eventHandler = { event, context in
       eventRecorder.record(event, in: context)
@@ -98,7 +98,7 @@ struct EventRecorderTests {
     let stream = Stream()
 
     var configuration = Configuration()
-    configuration.deliverExpectationCheckedEvents = true
+    configuration.eventHandlingOptions.isExpectationCheckedEventEnabled = true
     let eventRecorder = Event.ConsoleOutputRecorder(writingUsing: stream.write)
     configuration.eventHandler = { event, context in
       eventRecorder.record(event, in: context)
@@ -123,7 +123,7 @@ struct EventRecorderTests {
     let stream = Stream()
 
     var configuration = Configuration()
-    configuration.deliverExpectationCheckedEvents = true
+    configuration.eventHandlingOptions.isExpectationCheckedEventEnabled = true
     let eventRecorder = Event.ConsoleOutputRecorder(writingUsing: stream.write)
     configuration.eventHandler = { event, context in
       eventRecorder.record(event, in: context)
@@ -308,7 +308,7 @@ struct EventRecorderTests {
     let stream = Stream()
 
     var configuration = Configuration()
-    configuration.deliverExpectationCheckedEvents = true
+    configuration.eventHandlingOptions.isExpectationCheckedEventEnabled = true
     let eventRecorder = Event.JUnitXMLRecorder(writingUsing: stream.write)
     configuration.eventHandler = { event, context in
       eventRecorder.record(event, in: context)
diff --git a/Tests/TestingTests/IssueTests.swift b/Tests/TestingTests/IssueTests.swift
index 7402d9c4e..8e1e90b85 100644
--- a/Tests/TestingTests/IssueTests.swift
+++ b/Tests/TestingTests/IssueTests.swift
@@ -301,7 +301,7 @@ final class IssueTests: XCTestCase {
     let expectationChecked = expectation(description: "expectation checked")
 
     var configuration = Configuration()
-    configuration.deliverExpectationCheckedEvents = true
+    configuration.eventHandlingOptions.isExpectationCheckedEventEnabled = true
     configuration.eventHandler = { event, _ in
       guard case let .expectationChecked(expectation) = event.kind else {
         return
diff --git a/Tests/TestingTests/Runner.RuntimeStateTests.swift b/Tests/TestingTests/Runner.RuntimeStateTests.swift
index e4ee33079..1576c49e7 100644
--- a/Tests/TestingTests/Runner.RuntimeStateTests.swift
+++ b/Tests/TestingTests/Runner.RuntimeStateTests.swift
@@ -34,7 +34,7 @@ struct Runner_RuntimeStateTests {
     // an event to be posted during the test below without causing any real
     // issues to be recorded or otherwise confuse the testing harness.
     var configuration = Configuration.current ?? .init()
-    configuration.deliverExpectationCheckedEvents = true
+    configuration.eventHandlingOptions.isExpectationCheckedEventEnabled = true
 
     await Configuration.withCurrent(configuration) {
       await withTaskGroup(of: Void.self) { group in
diff --git a/Tests/TestingTests/RunnerTests.swift b/Tests/TestingTests/RunnerTests.swift
index 857cfdd81..335f8be37 100644
--- a/Tests/TestingTests/RunnerTests.swift
+++ b/Tests/TestingTests/RunnerTests.swift
@@ -426,7 +426,7 @@ final class RunnerTests: XCTestCase {
 
   func testExpectationCheckedEventHandlingWhenDisabled() async {
     var configuration = Configuration()
-    configuration.deliverExpectationCheckedEvents = false
+    configuration.eventHandlingOptions.isExpectationCheckedEventEnabled = false
     configuration.eventHandler = { event, _ in
       if case .expectationChecked = event.kind {
         XCTFail("Expectation checked event was posted unexpectedly")
@@ -459,7 +459,7 @@ final class RunnerTests: XCTestCase {
 #endif
 
     var configuration = Configuration()
-    configuration.deliverExpectationCheckedEvents = true
+    configuration.eventHandlingOptions.isExpectationCheckedEventEnabled = true
     configuration.eventHandler = { event, _ in
       guard case let .expectationChecked(expectation) = event.kind else {
         return

From 5b5bfcafc3fe5e3ccef0657d5e084f59bc86942a Mon Sep 17 00:00:00 2001
From: Stuart Montgomery <smontgomery@apple.com>
Date: Tue, 4 Feb 2025 17:00:21 -0600
Subject: [PATCH 19/32] Fixed extra space in output formatting

---
 .../Events/Recorder/Event.HumanReadableOutputRecorder.swift     | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift b/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift
index ef784a195..cdb877398 100644
--- a/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift
+++ b/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift
@@ -459,7 +459,7 @@ extension Event.HumanReadableOutputRecorder {
       let primaryMessage: Message = if parameterCount == 0 {
         Message(
           symbol: symbol,
-          stringValue: "\(_capitalizedTitle(for: test)) \(testName) recorded \(subject) \(atSourceLocation): \(issue.kind)",
+          stringValue: "\(_capitalizedTitle(for: test)) \(testName) recorded \(subject)\(atSourceLocation): \(issue.kind)",
           conciseStringValue: String(describing: issue.kind)
         )
       } else {

From c7ff8a22026e9bd2052c84cdf3f10987349330f3 Mon Sep 17 00:00:00 2001
From: Stuart Montgomery <smontgomery@apple.com>
Date: Tue, 4 Feb 2025 17:01:01 -0600
Subject: [PATCH 20/32] Adjust and add new console output tests

---
 Tests/TestingTests/EventRecorderTests.swift | 109 +++++++++++++++-----
 1 file changed, 82 insertions(+), 27 deletions(-)

diff --git a/Tests/TestingTests/EventRecorderTests.swift b/Tests/TestingTests/EventRecorderTests.swift
index 821d1ce60..2219ed54e 100644
--- a/Tests/TestingTests/EventRecorderTests.swift
+++ b/Tests/TestingTests/EventRecorderTests.swift
@@ -183,15 +183,20 @@ struct EventRecorderTests {
   @Test(
     "Issue counts are summed correctly on test end",
     arguments: [
-      ("f()", false, (total: 5, expected: 3)),
-      ("g()", false, (total: 2, expected: 1)),
-      ("PredictablyFailingTests", true, (total: 7, expected: 4)),
+      ("f()", ".* Test f\\(\\) failed after .+ seconds with 5 issues \\(including 3 known issues\\)\\."),
+      ("g()", ".* Test g\\(\\) failed after .+ seconds with 2 issues \\(including 1 known issue\\)\\."),
+      ("h()", ".* Test h\\(\\) passed after .+ seconds with 1 warning\\."),
+      ("i()", ".* Test i\\(\\) failed after .+ seconds with 2 issues \\(including 1 warning\\)\\."),
+      ("j()", ".* Test j\\(\\) passed after .+ seconds with 1 warning and 1 known issue\\."),
+      ("k()", ".* Test k\\(\\) passed after .+ seconds with 1 known issue\\."),
+      ("PredictablyFailingTests", ".* Suite PredictablyFailingTests failed after .+ seconds with 13 issues \\(including 3 warnings and 6 known issues\\)\\."),
     ]
   )
-  func issueCountSummingAtTestEnd(testName: String, isSuite: Bool, issueCount: (total: Int, expected: Int)) async throws {
+  func issueCountSummingAtTestEnd(testName: String, expectedPattern: String) async throws {
     let stream = Stream()
 
     var configuration = Configuration()
+    configuration.eventHandlingOptions.isWarningIssueRecordedEventEnabled = true
     let eventRecorder = Event.ConsoleOutputRecorder(writingUsing: stream.write)
     configuration.eventHandler = { event, context in
       eventRecorder.record(event, in: context)
@@ -204,28 +209,13 @@ struct EventRecorderTests {
       print(buffer, terminator: "")
     }
 
-    let testFailureRegex = Regex {
-      One(.anyGraphemeCluster)
-      " \(isSuite ? "Suite" : "Test") \(testName) failed "
-      ZeroOrMore(.any)
-      " with "
-      Capture { OneOrMore(.digit) } transform: { Int($0) }
-      " issue"
-      Optionally("s")
-      " (including "
-      Capture { OneOrMore(.digit) } transform: { Int($0) }
-      " known issue"
-      Optionally("s")
-      ")."
-    }
-    let match = try #require(
-      buffer
-        .split(whereSeparator: \.isNewline)
-        .compactMap(testFailureRegex.wholeMatch(in:))
-        .first
+    let expectedSuffixRegex = try Regex(expectedPattern)
+    _ = try #require(buffer
+      .split(whereSeparator: \.isNewline)
+      .compactMap(expectedSuffixRegex.wholeMatch(in:))
+      .first,
+      "buffer: \(buffer)"
     )
-    #expect(issueCount.total == match.output.1)
-    #expect(issueCount.expected == match.output.2)
   }
 #endif
 
@@ -294,8 +284,51 @@ struct EventRecorderTests {
         .compactMap(runFailureRegex.wholeMatch(in:))
         .first
     )
-    #expect(match.output.1 == 7)
-    #expect(match.output.2 == 4)
+    #expect(match.output.1 == 9)
+    #expect(match.output.2 == 5)
+  }
+
+  @Test("Issue counts are summed correctly on run end for a test with only warning issues")
+  @available(_regexAPI, *)
+  func warningIssueCountSummingAtRunEnd() async throws {
+    let stream = Stream()
+
+    var configuration = Configuration()
+    configuration.eventHandlingOptions.isWarningIssueRecordedEventEnabled = true
+    let eventRecorder = Event.ConsoleOutputRecorder(writingUsing: stream.write)
+    configuration.eventHandler = { event, context in
+      eventRecorder.record(event, in: context)
+    }
+
+    await runTestFunction(named: "h()", in: PredictablyFailingTests.self, configuration: configuration)
+
+    let buffer = stream.buffer.rawValue
+    if testsWithSignificantIOAreEnabled {
+      print(buffer, terminator: "")
+    }
+
+    let runFailureRegex = Regex {
+      One(.anyGraphemeCluster)
+      " Test run with "
+      OneOrMore(.digit)
+      " test"
+      Optionally("s")
+      " passed "
+      ZeroOrMore(.any)
+      " with "
+      Capture { OneOrMore(.digit) } transform: { Int($0) }
+      " warning"
+      Optionally("s")
+      "."
+    }
+    let match = try #require(
+      buffer
+        .split(whereSeparator: \.isNewline)
+        .compactMap(runFailureRegex.wholeMatch(in:))
+        .first,
+      "buffer: \(buffer)"
+    )
+    #expect(match.output.1 == 1)
   }
 #endif
 
@@ -510,4 +543,26 @@ struct EventRecorderTests {
       #expect(Bool(false))
     }
   }
+
+  @Test(.hidden) func h() {
+    Issue(kind: .unconditional, severity: .warning, comments: [], sourceContext: .init()).record()
+  }
+
+  @Test(.hidden) func i() {
+    Issue(kind: .unconditional, severity: .warning, comments: [], sourceContext: .init()).record()
+    #expect(Bool(false))
+  }
+
+  @Test(.hidden) func j() {
+    Issue(kind: .unconditional, severity: .warning, comments: [], sourceContext: .init()).record()
+    withKnownIssue {
+      #expect(Bool(false))
+    }
+  }
+
+  @Test(.hidden) func k() {
+    withKnownIssue {
+      Issue(kind: .unconditional, severity: .warning, comments: [], sourceContext: .init()).record()
+    }
+  }
 }

From 51c5327058c4434c80fb470d72adbaffd4da9381 Mon Sep 17 00:00:00 2001
From: Stuart Montgomery <smontgomery@apple.com>
Date: Mon, 3 Feb 2025 21:53:55 -0600
Subject: [PATCH 21/32] Generalize the infrastructure for enabling experimental
 features

---
 .../Testing/ABI/EntryPoints/EntryPoint.swift  |  28 ++---
 Sources/Testing/CMakeLists.txt                |   1 +
 .../Running/Configuration.Feature.swift       | 103 ++++++++++++++++++
 Sources/Testing/Running/Configuration.swift   |  56 +++++++++-
 Tests/TestingTests/ABIEntryPointTests.swift   |   2 +-
 .../TestSupport/TestingAdditions.swift        |  12 ++
 6 files changed, 187 insertions(+), 15 deletions(-)
 create mode 100644 Sources/Testing/Running/Configuration.Feature.swift

diff --git a/Sources/Testing/ABI/EntryPoints/EntryPoint.swift b/Sources/Testing/ABI/EntryPoints/EntryPoint.swift
index b12c0d8cf..8191627cc 100644
--- a/Sources/Testing/ABI/EntryPoints/EntryPoint.swift
+++ b/Sources/Testing/ABI/EntryPoints/EntryPoint.swift
@@ -454,7 +454,9 @@ func parseCommandLineArguments(from args: [String]) throws -> __CommandLineArgum
 /// - Throws: If an argument is invalid, such as a malformed regular expression.
 @_spi(ForToolsIntegrationOnly)
 public func configurationForEntryPoint(from args: __CommandLineArguments_v0) throws -> Configuration {
-  var configuration = Configuration()
+  // Pass the event stream version when initializing a configuration so it can
+  // be used to gate feature enablement.
+  var configuration = Configuration(version: args.eventStreamVersion)
 
   // Parallelization (on by default)
   configuration.isParallelizationEnabled = args.parallel ?? true
@@ -566,19 +568,19 @@ public func configurationForEntryPoint(from args: __CommandLineArguments_v0) thr
   configuration.exitTestHandler = ExitTest.handlerForEntryPoint()
 #endif
 
-  configuration.eventHandlingOptions.isWarningIssueRecordedEventEnabled = if (args.experimentalFeatures ?? []).contains("WarningIssues") {
-    true
-  } else {
-    switch args.eventStreamVersion {
-    case .some(...0):
-      // If the event stream version was explicitly specified to a value < 1,
-      // disable the warning issue event to maintain legacy behavior.
-      false
-    default:
-      // Otherwise the requested event stream version is ≥ 1, so don't change
-      // the warning issue event setting.
-      configuration.eventHandlingOptions.isWarningIssueRecordedEventEnabled
+  // Apply explicitly-enabled experimental features.
+  if let experimentalFeatures = args.experimentalFeatures {
+    // Validate the requested feature IDs and report an error if any are
+    // unrecognized.
+    let features = try experimentalFeatures.map { featureID in
+      guard let feature = Configuration.Feature.allCases.first(where: { $0.id == featureID }) else {
+        throw _EntryPointError.invalidArgument("--enable-experimental-feature", value: featureID)
+      }
+      return feature
     }
+
+    // Enable the requested features.
+    configuration.enableFeatures(features)
   }
 
   return configuration
diff --git a/Sources/Testing/CMakeLists.txt b/Sources/Testing/CMakeLists.txt
index 5971a57b4..a1e1d6f6d 100644
--- a/Sources/Testing/CMakeLists.txt
+++ b/Sources/Testing/CMakeLists.txt
@@ -50,6 +50,7 @@ add_library(Testing
   Parameterization/Test.Case.swift
   Parameterization/TypeInfo.swift
   Running/Configuration.swift
+  Running/Configuration.Feature.swift
   Running/Configuration.TestFilter.swift
   Running/Configuration+EventHandling.swift
   Running/Runner.Plan.swift
diff --git a/Sources/Testing/Running/Configuration.Feature.swift b/Sources/Testing/Running/Configuration.Feature.swift
new file mode 100644
index 000000000..a4f9ab115
--- /dev/null
+++ b/Sources/Testing/Running/Configuration.Feature.swift
@@ -0,0 +1,103 @@
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for Swift project authors
+//
+
+extension Configuration {
+  /// A type representing the details of feature of the testing library,
+  /// including whether it's enabled (by default or explicitly) and when it was
+  /// introduced.
+  ///
+  /// Features are uniquely identified by the value of their ``id`` property.
+  struct Feature: Sendable, Identifiable {
+    /// The identifier for this feature.
+    ///
+    /// A feature's identifier is typically a short, human readable,
+    /// UpperCamelCased string. It must be unique among all features applied to
+    /// the testing library, and may be passed by a user to explicitly enable
+    /// the feature before it is enabled by default.
+    var id: String
+
+    /// The key path rooted at `Configuration` which may be used to modify a
+    /// a setting controlling whether this feature is enabled.
+    var configurationKeyPath: any WritableKeyPath<Configuration, Bool> & Sendable
+
+    /// Whether this feature is enabled by default.
+    ///
+    /// The value of this property reflects the "out of the box" default
+    /// enablement status of this feature. Its value does _not_ reflect whether
+    /// a user explicitly enabled the feature; for that, see ``isExplicitlyEnabled``.
+    ///
+    /// ## See Also
+    ///
+    /// - ``isEnabledExplicitly``
+    var isEnabledByDefault: Bool
+
+    /// Whether this feature was explicitly enabled by a user.
+    ///
+    /// The value of this property reflects whether a user explicitly enabled
+    /// this feature by e.g. passing an opt-in flag or toggling an opt-in
+    /// setting in an integrated tool. Typically, this overrides the default
+    /// enablement status indicated by the value of ``isEnabledByDefault``.
+    ///
+    /// ## See Also
+    ///
+    /// - ``isEnabledByDefault``
+    var isEnabledExplicitly: Bool = false
+
+    /// The event stream/ABI version in which this feature was, or is expected
+    /// to be, first introduced.
+    var versionIntroduced: Int
+
+    fileprivate init(
+      id: String,
+      configurationKeyPath: any WritableKeyPath<Configuration, Bool> & Sendable,
+      isEnabledByDefault: Bool,
+      versionIntroduced: Int
+    ) {
+      self.id = id
+      self.configurationKeyPath = configurationKeyPath
+      self.isEnabledByDefault = isEnabledByDefault
+      self.versionIntroduced = versionIntroduced
+    }
+  }
+}
+
+extension Configuration.Feature: Hashable {
+  static func ==(lhs: Self, rhs: Self) -> Bool {
+    lhs.id == rhs.id
+  }
+
+  func hash(into hasher: inout Hasher) {
+    hasher.combine(id)
+  }
+}
+
+// MARK: - Feature list
+
+extension Configuration.Feature: CaseIterable {
+  static var allCases: Set<Self> {
+    [
+      warningIssues,
+    ]
+  }
+
+  /// The warning issues feature.
+  ///
+  /// ## See Also
+  ///
+  /// - [swiftlang/swift-testing#931](https://github.com/swiftlang/swift-testing/pull/931)
+  static var warningIssues: Self {
+    Self(
+      id: "WarningIssues",
+      configurationKeyPath: \.eventHandlingOptions.isWarningIssueRecordedEventEnabled,
+      isEnabledByDefault: false,
+      versionIntroduced: 1,
+    )
+  }
+}
diff --git a/Sources/Testing/Running/Configuration.swift b/Sources/Testing/Running/Configuration.swift
index 868cb16a2..f1c05fa38 100644
--- a/Sources/Testing/Running/Configuration.swift
+++ b/Sources/Testing/Running/Configuration.swift
@@ -13,7 +13,61 @@
 public struct Configuration: Sendable {
   /// Initialize an instance of this type representing the default
   /// configuration.
-  public init() {}
+  public init() {
+    self.init(version: nil)
+  }
+
+  /// Initialize an instance of this type representing the default configuration,
+  /// gating features based on the specified version (if any) or their default
+  /// enablement status.
+  ///
+  /// - Parameters:
+  ///   - version: The event stream/ABI version to use when determining features
+  ///     to enable, if any. Passing `nil` causes this initialized to fall back
+  ///     to ``Feature/isEnabledByDefault`` to determine whether each feature
+  ///     should be enabled.
+  init(version: Int?) {
+    for feature in features {
+      self[keyPath: feature.configurationKeyPath] = if let version, version < feature.versionIntroduced {
+        false
+      } else {
+        feature.isEnabledByDefault
+      }
+    }
+  }
+
+  // MARK: - Features
+
+  /// The set of features applied to this configuration.
+  ///
+  /// The features of a configuration may affect its settings, depending on the
+  /// enablement status of each feature or the version in which is was first
+  /// introduced compared with the event stream/ABI version the configuration
+  /// will be configured to run with.
+  ///
+  /// To enable additional features, use ``enableFeatures(_:)``.
+  private(set) var features: Set<Feature> = Feature.allCases
+
+  /// Enable the specified features.
+  ///
+  /// - Parameters:
+  ///   - features: The features to enable.
+  mutating func enableFeatures(_ featuresToEnable: some Sequence<Feature>) {
+    let featuresToEnable = Set(featuresToEnable)
+
+    for var feature in features {
+      guard featuresToEnable.contains(feature) else {
+        continue
+      }
+
+      // Note that this feature was enabled explicitly, for tracking purposes.
+      feature.isEnabledExplicitly = true
+      features.update(with: feature)
+
+      // Enable the configuration setting for this feature.
+      self[keyPath: feature.configurationKeyPath] = true
+    }
+  }
 
   // MARK: - Parallelization
 
diff --git a/Tests/TestingTests/ABIEntryPointTests.swift b/Tests/TestingTests/ABIEntryPointTests.swift
index 95f75c215..73ae31f5c 100644
--- a/Tests/TestingTests/ABIEntryPointTests.swift
+++ b/Tests/TestingTests/ABIEntryPointTests.swift
@@ -174,7 +174,7 @@ struct ABIEntryPointTests {
     arguments.filter = ["_recordWarningIssue"]
     arguments.includeHiddenTests = true
     arguments.eventStreamVersion = 0
-    arguments.experimentalFeatures = ["WarningIssues"]
+    arguments.enableFeatures(.warningIssues)
     arguments.verbosity = .min
 
     let result = try await confirmation("Warning issue recorded", expectedCount: 1) { issueRecorded in
diff --git a/Tests/TestingTests/TestSupport/TestingAdditions.swift b/Tests/TestingTests/TestSupport/TestingAdditions.swift
index 906bf737a..9f708f91b 100644
--- a/Tests/TestingTests/TestSupport/TestingAdditions.swift
+++ b/Tests/TestingTests/TestSupport/TestingAdditions.swift
@@ -386,3 +386,15 @@ extension SourceContext {
     self.init(backtrace: .current(), sourceLocation: sourceLocation)
   }
 }
+
+extension __CommandLineArguments_v0 {
+  /// Enable the specified feature(s) in this command line arguments instance.
+  ///
+  /// - Parameters:
+  ///   - features: The feature(s) to enable.
+  mutating func enableFeatures(_ features: Configuration.Feature...) {
+    var experimentalFeatures = self.experimentalFeatures ?? []
+    experimentalFeatures.append(contentsOf: features.map(\.id))
+    self.experimentalFeatures = experimentalFeatures
+  }
+}

From 39f8ac63e6a43db8c16e09e7a12e5abc92e21025 Mon Sep 17 00:00:00 2001
From: Stuart Montgomery <smontgomery@apple.com>
Date: Wed, 5 Feb 2025 11:21:14 -0600
Subject: [PATCH 22/32] Make 'includeHiddenTests' property internal since it's
 only needed by the unit tests

---
 Sources/Testing/ABI/EntryPoints/EntryPoint.swift | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Sources/Testing/ABI/EntryPoints/EntryPoint.swift b/Sources/Testing/ABI/EntryPoints/EntryPoint.swift
index 8191627cc..04f447c98 100644
--- a/Sources/Testing/ABI/EntryPoints/EntryPoint.swift
+++ b/Sources/Testing/ABI/EntryPoints/EntryPoint.swift
@@ -275,7 +275,7 @@ public struct __CommandLineArguments_v0: Sendable {
   ///
   /// This property is intended for use in testing the testing library itself.
   /// It is not parsed as a command-line argument.
-  public var includeHiddenTests: Bool?
+  var includeHiddenTests: Bool?
 
   /// The value of the `--repetitions` argument.
   public var repetitions: Int?

From a101445d626150831db3bb6da4010707315e77d1 Mon Sep 17 00:00:00 2001
From: Stuart Montgomery <smontgomery@apple.com>
Date: Wed, 5 Feb 2025 11:23:15 -0600
Subject: [PATCH 23/32] Add custom decoding logic to gracefully decode
 Issue.Snapshot instances which lack the severity field

---
 Sources/Testing/Issues/Issue.swift | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/Sources/Testing/Issues/Issue.swift b/Sources/Testing/Issues/Issue.swift
index bcd7b3c90..5d7449b7b 100644
--- a/Sources/Testing/Issues/Issue.swift
+++ b/Sources/Testing/Issues/Issue.swift
@@ -322,6 +322,17 @@ extension Issue {
       self.isKnown = issue.isKnown
     }
 
+    public init(from decoder: any Decoder) throws {
+      let container = try decoder.container(keyedBy: CodingKeys.self)
+      self.kind = try container.decode(Issue.Kind.Snapshot.self, forKey: .kind)
+      self.comments = try container.decode([Comment].self, forKey: .comments)
+      self.sourceContext = try container.decode(SourceContext.self, forKey: .sourceContext)
+      self.isKnown = try container.decode(Bool.self, forKey: .isKnown)
+
+      // Severity is a new field, so fall back to .error if it's not present.
+      self.severity = try container.decodeIfPresent(Issue.Severity.self, forKey: .severity) ?? .error
+    }
+
     /// The error which was associated with this issue, if any.
     ///
     /// The value of this property is non-`nil` when ``kind-swift.property`` is

From d7c8bdcc6d1db7d5228622fcfc8f86c5d004d90e Mon Sep 17 00:00:00 2001
From: Stuart Montgomery <smontgomery@apple.com>
Date: Wed, 5 Feb 2025 11:23:29 -0600
Subject: [PATCH 24/32] Revert "Generalize the infrastructure for enabling
 experimental features"

This reverts commit 51c5327058c4434c80fb470d72adbaffd4da9381.
---
 .../Testing/ABI/EntryPoints/EntryPoint.swift  |  41 ++++---
 Sources/Testing/CMakeLists.txt                |   1 -
 .../Running/Configuration.Feature.swift       | 103 ------------------
 Sources/Testing/Running/Configuration.swift   |  56 +---------
 Tests/TestingTests/ABIEntryPointTests.swift   |   2 +-
 .../TestSupport/TestingAdditions.swift        |  12 --
 6 files changed, 22 insertions(+), 193 deletions(-)
 delete mode 100644 Sources/Testing/Running/Configuration.Feature.swift

diff --git a/Sources/Testing/ABI/EntryPoints/EntryPoint.swift b/Sources/Testing/ABI/EntryPoints/EntryPoint.swift
index 04f447c98..06b6f7767 100644
--- a/Sources/Testing/ABI/EntryPoints/EntryPoint.swift
+++ b/Sources/Testing/ABI/EntryPoints/EntryPoint.swift
@@ -286,12 +286,12 @@ public struct __CommandLineArguments_v0: Sendable {
   /// The value of the `--experimental-attachments-path` argument.
   public var experimentalAttachmentsPath: String?
 
-  /// The value(s) of the `--enable-experimental-feature` argument(s),
-  /// indicating the name(s) of experimental features to enable.
+  /// Whether or not the experimental warning issue severity feature should be
+  /// enabled.
   ///
-  /// The value of this property is not yet populated by parsing command-line
-  /// arguments, but may be in the future.
-  public var experimentalFeatures: [String]?
+  /// This property is intended for use in testing the testing library itself.
+  /// It is not parsed as a command-line argument.
+  var isWarningIssueRecordedEventEnabled: Bool?
 }
 
 extension __CommandLineArguments_v0: Codable {
@@ -314,7 +314,7 @@ extension __CommandLineArguments_v0: Codable {
     case repetitions
     case repeatUntil
     case experimentalAttachmentsPath
-    case experimentalFeatures
+    case isWarningIssueRecordedEventEnabled
   }
 }
 
@@ -454,9 +454,7 @@ func parseCommandLineArguments(from args: [String]) throws -> __CommandLineArgum
 /// - Throws: If an argument is invalid, such as a malformed regular expression.
 @_spi(ForToolsIntegrationOnly)
 public func configurationForEntryPoint(from args: __CommandLineArguments_v0) throws -> Configuration {
-  // Pass the event stream version when initializing a configuration so it can
-  // be used to gate feature enablement.
-  var configuration = Configuration(version: args.eventStreamVersion)
+  var configuration = Configuration()
 
   // Parallelization (on by default)
   configuration.isParallelizationEnabled = args.parallel ?? true
@@ -568,19 +566,20 @@ public func configurationForEntryPoint(from args: __CommandLineArguments_v0) thr
   configuration.exitTestHandler = ExitTest.handlerForEntryPoint()
 #endif
 
-  // Apply explicitly-enabled experimental features.
-  if let experimentalFeatures = args.experimentalFeatures {
-    // Validate the requested feature IDs and report an error if any are
-    // unrecognized.
-    let features = try experimentalFeatures.map { featureID in
-      guard let feature = Configuration.Feature.allCases.first(where: { $0.id == featureID }) else {
-        throw _EntryPointError.invalidArgument("--enable-experimental-feature", value: featureID)
-      }
-      return feature
+  // Warning issues (experimental).
+  if args.isWarningIssueRecordedEventEnabled == true {
+    configuration.eventHandlingOptions.isWarningIssueRecordedEventEnabled = true
+  } else {
+    switch args.eventStreamVersion {
+    case .some(...0):
+      // If the event stream version was explicitly specified to a value < 1,
+      // disable the warning issue event to maintain legacy behavior.
+      configuration.eventHandlingOptions.isWarningIssueRecordedEventEnabled = false
+    default:
+      // Otherwise the requested event stream version is ≥ 1, so don't change
+      // the warning issue event setting.
+      break
     }
-
-    // Enable the requested features.
-    configuration.enableFeatures(features)
   }
 
   return configuration
diff --git a/Sources/Testing/CMakeLists.txt b/Sources/Testing/CMakeLists.txt
index a1e1d6f6d..5971a57b4 100644
--- a/Sources/Testing/CMakeLists.txt
+++ b/Sources/Testing/CMakeLists.txt
@@ -50,7 +50,6 @@ add_library(Testing
   Parameterization/Test.Case.swift
   Parameterization/TypeInfo.swift
   Running/Configuration.swift
-  Running/Configuration.Feature.swift
   Running/Configuration.TestFilter.swift
   Running/Configuration+EventHandling.swift
   Running/Runner.Plan.swift
diff --git a/Sources/Testing/Running/Configuration.Feature.swift b/Sources/Testing/Running/Configuration.Feature.swift
deleted file mode 100644
index a4f9ab115..000000000
--- a/Sources/Testing/Running/Configuration.Feature.swift
+++ /dev/null
@@ -1,103 +0,0 @@
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2025 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for Swift project authors
-//
-
-extension Configuration {
-  /// A type representing the details of feature of the testing library,
-  /// including whether it's enabled (by default or explicitly) and when it was
-  /// introduced.
-  ///
-  /// Features are uniquely identified by the value of their ``id`` property.
-  struct Feature: Sendable, Identifiable {
-    /// The identifier for this feature.
-    ///
-    /// A feature's identifier is typically a short, human readable,
-    /// UpperCamelCased string. It must be unique among all features applied to
-    /// the testing library, and may be passed by a user to explicitly enable
-    /// the feature before it is enabled by default.
-    var id: String
-
-    /// The key path rooted at `Configuration` which may be used to modify a
-    /// a setting controlling whether this feature is enabled.
-    var configurationKeyPath: any WritableKeyPath<Configuration, Bool> & Sendable
-
-    /// Whether this feature is enabled by default.
-    ///
-    /// The value of this property reflects the "out of the box" default
-    /// enablement status of this feature. Its value does _not_ reflect whether
-    /// a user explicitly enabled the feature; for that, see ``isExplicitlyEnabled``.
-    ///
-    /// ## See Also
-    ///
-    /// - ``isEnabledExplicitly``
-    var isEnabledByDefault: Bool
-
-    /// Whether this feature was explicitly enabled by a user.
-    ///
-    /// The value of this property reflects whether a user explicitly enabled
-    /// this feature by e.g. passing an opt-in flag or toggling an opt-in
-    /// setting in an integrated tool. Typically, this overrides the default
-    /// enablement status indicated by the value of ``isEnabledByDefault``.
-    ///
-    /// ## See Also
-    ///
-    /// - ``isEnabledByDefault``
-    var isEnabledExplicitly: Bool = false
-
-    /// The event stream/ABI version in which this feature was, or is expected
-    /// to be, first introduced.
-    var versionIntroduced: Int
-
-    fileprivate init(
-      id: String,
-      configurationKeyPath: any WritableKeyPath<Configuration, Bool> & Sendable,
-      isEnabledByDefault: Bool,
-      versionIntroduced: Int
-    ) {
-      self.id = id
-      self.configurationKeyPath = configurationKeyPath
-      self.isEnabledByDefault = isEnabledByDefault
-      self.versionIntroduced = versionIntroduced
-    }
-  }
-}
-
-extension Configuration.Feature: Hashable {
-  static func ==(lhs: Self, rhs: Self) -> Bool {
-    lhs.id == rhs.id
-  }
-
-  func hash(into hasher: inout Hasher) {
-    hasher.combine(id)
-  }
-}
-
-// MARK: - Feature list
-
-extension Configuration.Feature: CaseIterable {
-  static var allCases: Set<Self> {
-    [
-      warningIssues,
-    ]
-  }
-
-  /// The warning issues feature.
-  ///
-  /// ## See Also
-  ///
-  /// - [swiftlang/swift-testing#931](https://github.com/swiftlang/swift-testing/pull/931)
-  static var warningIssues: Self {
-    Self(
-      id: "WarningIssues",
-      configurationKeyPath: \.eventHandlingOptions.isWarningIssueRecordedEventEnabled,
-      isEnabledByDefault: false,
-      versionIntroduced: 1,
-    )
-  }
-}
diff --git a/Sources/Testing/Running/Configuration.swift b/Sources/Testing/Running/Configuration.swift
index f1c05fa38..868cb16a2 100644
--- a/Sources/Testing/Running/Configuration.swift
+++ b/Sources/Testing/Running/Configuration.swift
@@ -13,61 +13,7 @@
 public struct Configuration: Sendable {
   /// Initialize an instance of this type representing the default
   /// configuration.
-  public init() {
-    self.init(version: nil)
-  }
-
-  /// Initialize an instance of this type representing the default configuration,
-  /// gating features based on the specified version (if any) or their default
-  /// enablement status.
-  ///
-  /// - Parameters:
-  ///   - version: The event stream/ABI version to use when determining features
-  ///     to enable, if any. Passing `nil` causes this initialized to fall back
-  ///     to ``Feature/isEnabledByDefault`` to determine whether each feature
-  ///     should be enabled.
-  init(version: Int?) {
-    for feature in features {
-      self[keyPath: feature.configurationKeyPath] = if let version, version < feature.versionIntroduced {
-        false
-      } else {
-        feature.isEnabledByDefault
-      }
-    }
-  }
-
-  // MARK: - Features
-
-  /// The set of features applied to this configuration.
-  ///
-  /// The features of a configuration may affect its settings, depending on the
-  /// enablement status of each feature or the version in which is was first
-  /// introduced compared with the event stream/ABI version the configuration
-  /// will be configured to run with.
-  ///
-  /// To enable additional features, use ``enableFeatures(_:)``.
-  private(set) var features: Set<Feature> = Feature.allCases
-
-  /// Enable the specified features.
-  ///
-  /// - Parameters:
-  ///   - features: The features to enable.
-  mutating func enableFeatures(_ featuresToEnable: some Sequence<Feature>) {
-    let featuresToEnable = Set(featuresToEnable)
-
-    for var feature in features {
-      guard featuresToEnable.contains(feature) else {
-        continue
-      }
-
-      // Note that this feature was enabled explicitly, for tracking purposes.
-      feature.isEnabledExplicitly = true
-      features.update(with: feature)
-
-      // Enable the configuration setting for this feature.
-      self[keyPath: feature.configurationKeyPath] = true
-    }
-  }
+  public init() {}
 
   // MARK: - Parallelization
 
diff --git a/Tests/TestingTests/ABIEntryPointTests.swift b/Tests/TestingTests/ABIEntryPointTests.swift
index 73ae31f5c..d6ca8e1d7 100644
--- a/Tests/TestingTests/ABIEntryPointTests.swift
+++ b/Tests/TestingTests/ABIEntryPointTests.swift
@@ -174,7 +174,7 @@ struct ABIEntryPointTests {
     arguments.filter = ["_recordWarningIssue"]
     arguments.includeHiddenTests = true
     arguments.eventStreamVersion = 0
-    arguments.enableFeatures(.warningIssues)
+    arguments.isWarningIssueRecordedEventEnabled = true
     arguments.verbosity = .min
 
     let result = try await confirmation("Warning issue recorded", expectedCount: 1) { issueRecorded in
diff --git a/Tests/TestingTests/TestSupport/TestingAdditions.swift b/Tests/TestingTests/TestSupport/TestingAdditions.swift
index 9f708f91b..906bf737a 100644
--- a/Tests/TestingTests/TestSupport/TestingAdditions.swift
+++ b/Tests/TestingTests/TestSupport/TestingAdditions.swift
@@ -386,15 +386,3 @@ extension SourceContext {
     self.init(backtrace: .current(), sourceLocation: sourceLocation)
   }
 }
-
-extension __CommandLineArguments_v0 {
-  /// Enable the specified feature(s) in this command line arguments instance.
-  ///
-  /// - Parameters:
-  ///   - features: The feature(s) to enable.
-  mutating func enableFeatures(_ features: Configuration.Feature...) {
-    var experimentalFeatures = self.experimentalFeatures ?? []
-    experimentalFeatures.append(contentsOf: features.map(\.id))
-    self.experimentalFeatures = experimentalFeatures
-  }
-}

From b64d7a3aec1ec18ea45c7186a5a1f90c11e3696f Mon Sep 17 00:00:00 2001
From: Stuart Montgomery <smontgomery@apple.com>
Date: Wed, 5 Feb 2025 17:24:56 -0600
Subject: [PATCH 25/32] Avoid needing to serialize the new internal properties
 on __CommandLineArguments_v0 by calling the Swift entry point directly
 instead of the ABI entry point

---
 .../Testing/ABI/EntryPoints/EntryPoint.swift  |  4 +-
 Tests/TestingTests/ABIEntryPointTests.swift   | 79 +-----------------
 Tests/TestingTests/EntryPointTests.swift      | 82 +++++++++++++++++++
 3 files changed, 87 insertions(+), 78 deletions(-)
 create mode 100644 Tests/TestingTests/EntryPointTests.swift

diff --git a/Sources/Testing/ABI/EntryPoints/EntryPoint.swift b/Sources/Testing/ABI/EntryPoints/EntryPoint.swift
index 06b6f7767..89094c88f 100644
--- a/Sources/Testing/ABI/EntryPoints/EntryPoint.swift
+++ b/Sources/Testing/ABI/EntryPoints/EntryPoint.swift
@@ -20,6 +20,8 @@ private import _TestingInternals
 ///     writes events to the standard error stream in addition to passing them
 ///     to this function.
 ///
+/// - Returns: An exit code representing the result of running tests.
+///
 /// External callers cannot call this function directly. The can use
 /// ``ABIv0/entryPoint-swift.type.property`` to get a reference to an ABI-stable
 /// version of this function.
@@ -310,11 +312,9 @@ extension __CommandLineArguments_v0: Codable {
     case eventStreamVersion
     case filter
     case skip
-    case includeHiddenTests
     case repetitions
     case repeatUntil
     case experimentalAttachmentsPath
-    case isWarningIssueRecordedEventEnabled
   }
 }
 
diff --git a/Tests/TestingTests/ABIEntryPointTests.swift b/Tests/TestingTests/ABIEntryPointTests.swift
index d6ca8e1d7..86ede749e 100644
--- a/Tests/TestingTests/ABIEntryPointTests.swift
+++ b/Tests/TestingTests/ABIEntryPointTests.swift
@@ -54,7 +54,7 @@ struct ABIEntryPointTests {
   ) async throws -> CInt {
 #if !SWT_NO_DYNAMIC_LINKING
     // Get the ABI entry point by dynamically looking it up at runtime.
-    let copyABIEntryPoint_v0 = try _withTestingLibraryImageAddress { testingLibrary in
+    let copyABIEntryPoint_v0 = try withTestingLibraryImageAddress { testingLibrary in
       try #require(
         symbol(in: testingLibrary, named: "swt_copyABIEntryPoint_v0").map {
           unsafeBitCast($0, to: (@convention(c) () -> UnsafeMutableRawPointer).self)
@@ -127,70 +127,6 @@ struct ABIEntryPointTests {
     }
   }
 
-  @Test("v0 entry point filter with filtering of hidden tests enabled")
-  func v0_hiddenTests() async throws {
-    var arguments = __CommandLineArguments_v0()
-    arguments.filter = ["_someHiddenTest"]
-    arguments.includeHiddenTests = true
-    arguments.eventStreamVersion = 0
-    arguments.verbosity = .min
-
-    try await confirmation("Test event started", expectedCount: 1) { testMatched in
-      _ = try await _invokeEntryPointV0(passing: arguments) { recordJSON in
-        let record = try! JSON.decode(ABIv0.Record.self, from: recordJSON)
-        if case let .event(event) = record.kind, case .testStarted = event.kind {
-          testMatched()
-        }
-      }
-    }
-  }
-
-  @Test("v0 entry point with WarningIssues feature enabled exits with success if all issues have severity < .error")
-  func v0_warningIssues() async throws {
-    var arguments = __CommandLineArguments_v0()
-    arguments.filter = ["_recordWarningIssue"]
-    arguments.includeHiddenTests = true
-    arguments.eventStreamVersion = 0
-    arguments.verbosity = .min
-
-    let result = try await confirmation("Test matched", expectedCount: 1) { testMatched in
-      try await _invokeEntryPointV0(passing: arguments) { recordJSON in
-        let record = try! JSON.decode(ABIv0.Record.self, from: recordJSON)
-        if case let .event(event) = record.kind {
-          if case .testStarted = event.kind {
-            testMatched()
-          } else if case .issueRecorded = event.kind, let issue = event.issue {
-            Issue.record("Unexpected issue \(issue) was recorded to the event handler of a v0 entry point.")
-          }
-        }
-      }
-    }
-    #expect(result)
-  }
-
-  @Test("v0 entry point with WarningIssues feature enabled propagates warning issues and exits with success if all issues have severity < .error")
-  func v0_warningIssuesEnabled() async throws {
-    var arguments = __CommandLineArguments_v0()
-    arguments.filter = ["_recordWarningIssue"]
-    arguments.includeHiddenTests = true
-    arguments.eventStreamVersion = 0
-    arguments.isWarningIssueRecordedEventEnabled = true
-    arguments.verbosity = .min
-
-    let result = try await confirmation("Warning issue recorded", expectedCount: 1) { issueRecorded in
-      try await _invokeEntryPointV0(passing: arguments) { recordJSON in
-        let record = try! JSON.decode(ABIv0.Record.self, from: recordJSON)
-        if case let .event(event) = record.kind {
-          if case .issueRecorded = event.kind, let issue = event.issue {
-            #expect(issue._severity == .warning)
-            issueRecorded()
-          }
-        }
-      }
-    }
-    #expect(result)
-  }
-
   private func _invokeEntryPointV0(
     passing arguments: __CommandLineArguments_v0,
     recordHandler: @escaping @Sendable (_ recordJSON: UnsafeRawBufferPointer) -> Void = { _ in }
@@ -201,7 +137,7 @@ struct ABIEntryPointTests {
     // NOTE: The standard Linux linker does not allow exporting symbols from
     // executables, so dlsym() does not let us find this function on that
     // platform when built as an executable rather than a dynamic library.
-    let abiv0_getEntryPoint = try _withTestingLibraryImageAddress { testingLibrary in
+    let abiv0_getEntryPoint = try withTestingLibraryImageAddress { testingLibrary in
       try #require(
         symbol(in: testingLibrary, named: "swt_abiv0_getEntryPoint").map {
           unsafeBitCast($0, to: (@convention(c) () -> UnsafeRawPointer).self)
@@ -235,7 +171,7 @@ struct ABIEntryPointTests {
 }
 
 #if !SWT_NO_DYNAMIC_LINKING
-private func _withTestingLibraryImageAddress<R>(_ body: (ImageAddress?) throws -> R) throws -> R {
+private func withTestingLibraryImageAddress<R>(_ body: (ImageAddress?) throws -> R) throws -> R {
   let addressInTestingLibrary = unsafeBitCast(ABIv0.entryPoint, to: UnsafeRawPointer.self)
 
   var testingLibraryAddress: ImageAddress?
@@ -266,12 +202,3 @@ private func _withTestingLibraryImageAddress<R>(_ body: (ImageAddress?) throws -
 }
 #endif
 #endif
-
-// MARK: - Fixtures
-
-@Test(.hidden) private func _someHiddenTest() {}
-
-@Test(.hidden) private func _recordWarningIssue() {
-  // Intentionally _only_ record issues with warning (or lower) severity.
-  Issue(kind: .unconditional, severity: .warning, comments: [], sourceContext: .init()).record()
-}
diff --git a/Tests/TestingTests/EntryPointTests.swift b/Tests/TestingTests/EntryPointTests.swift
new file mode 100644
index 000000000..fb77643f7
--- /dev/null
+++ b/Tests/TestingTests/EntryPointTests.swift
@@ -0,0 +1,82 @@
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for Swift project authors
+//
+
+@testable @_spi(Experimental) @_spi(ForToolsIntegrationOnly) import Testing
+private import _TestingInternals
+
+@Suite("Entry point tests")
+struct EntryPointTests {
+  @Test("Entry point filter with filtering of hidden tests enabled")
+  func hiddenTests() async throws {
+    var arguments = __CommandLineArguments_v0()
+    arguments.filter = ["_someHiddenTest"]
+    arguments.includeHiddenTests = true
+    arguments.eventStreamVersion = 0
+    arguments.verbosity = .min
+
+    await confirmation("Test event started", expectedCount: 1) { testMatched in
+      _ = await entryPoint(passing: arguments) { event, context in
+        if case .testStarted = event.kind {
+          testMatched()
+        }
+      }
+    }
+  }
+
+  @Test("Entry point with WarningIssues feature enabled exits with success if all issues have severity < .error")
+  func warningIssues() async throws {
+    var arguments = __CommandLineArguments_v0()
+    arguments.filter = ["_recordWarningIssue"]
+    arguments.includeHiddenTests = true
+    arguments.eventStreamVersion = 0
+    arguments.verbosity = .min
+
+    let exitCode = await confirmation("Test matched", expectedCount: 1) { testMatched in
+      await entryPoint(passing: arguments) { event, context in
+        if case .testStarted = event.kind {
+          testMatched()
+        } else if case let .issueRecorded(issue) = event.kind {
+          Issue.record("Unexpected issue \(issue) was recorded.")
+        }
+      }
+    }
+    #expect(exitCode == EXIT_SUCCESS)
+  }
+
+  @Test("Entry point with WarningIssues feature enabled propagates warning issues and exits with success if all issues have severity < .error")
+  func warningIssuesEnabled() async throws {
+    var arguments = __CommandLineArguments_v0()
+    arguments.filter = ["_recordWarningIssue"]
+    arguments.includeHiddenTests = true
+    arguments.eventStreamVersion = 0
+    arguments.isWarningIssueRecordedEventEnabled = true
+    arguments.verbosity = .min
+
+    let exitCode = await confirmation("Warning issue recorded", expectedCount: 1) { issueRecorded in
+      await entryPoint(passing: arguments) { event, context in
+        if case let .issueRecorded(issue) = event.kind {
+          #expect(issue.severity == .warning)
+          issueRecorded()
+        }
+      }
+    }
+    #expect(exitCode == EXIT_SUCCESS)
+  }
+
+}
+
+// MARK: - Fixtures
+
+@Test(.hidden) private func _someHiddenTest() {}
+
+@Test(.hidden) private func _recordWarningIssue() {
+  // Intentionally _only_ record issues with warning (or lower) severity.
+  Issue(kind: .unconditional, severity: .warning, comments: [], sourceContext: .init()).record()
+}

From 8902a96f660a82e52fe0b41623ccbcad45d2937a Mon Sep 17 00:00:00 2001
From: Stuart Montgomery <smontgomery@apple.com>
Date: Fri, 7 Feb 2025 14:35:58 -0600
Subject: [PATCH 26/32] Various PR feedback

---
 Documentation/ABI/JSON.md                     |  9 +++++++
 .../ABI/v0/Encoded/ABIv0.EncodedIssue.swift   |  2 +-
 Sources/Testing/Events/Event.swift            | 20 ---------------
 .../Running/Configuration+EventHandling.swift | 20 +++++++++++++++
 Sources/Testing/Running/Configuration.swift   |  3 ---
 Tests/TestingTests/ConfigurationTests.swift   | 25 +++++++++++++++++++
 Tests/TestingTests/EntryPointTests.swift      |  1 -
 7 files changed, 55 insertions(+), 25 deletions(-)
 create mode 100644 Tests/TestingTests/ConfigurationTests.swift

diff --git a/Documentation/ABI/JSON.md b/Documentation/ABI/JSON.md
index 2fcf4b268..44053ff2c 100644
--- a/Documentation/ABI/JSON.md
+++ b/Documentation/ABI/JSON.md
@@ -220,3 +220,12 @@ sufficient information to display the event in a human-readable format.
   ["testID": <test-id>,
     ["testCase": <test-case>]]
 -->
+
+## Version history
+
+- Version 1 (unreleased)
+  - Introduced issue severity, with a new "warning" severity level which is
+    lower than the default "error" level. Clients upgrading from v0 should
+    begin consulting the severity of recorded issues to determine whether the
+    associated test should be marked as failing.
+- Version 0 (Initial ABI version)
diff --git a/Sources/Testing/ABI/v0/Encoded/ABIv0.EncodedIssue.swift b/Sources/Testing/ABI/v0/Encoded/ABIv0.EncodedIssue.swift
index 7c5b5185a..97c051d28 100644
--- a/Sources/Testing/ABI/v0/Encoded/ABIv0.EncodedIssue.swift
+++ b/Sources/Testing/ABI/v0/Encoded/ABIv0.EncodedIssue.swift
@@ -19,7 +19,7 @@ extension ABIv0 {
     /// An enumeration representing the level of severity of a recorded issue.
     ///
     /// For descriptions of individual cases, see ``Issue/Severity-swift.enum``.
-    enum Severity: String {
+    enum Severity: String, Sendable {
       case warning
       case error
     }
diff --git a/Sources/Testing/Events/Event.swift b/Sources/Testing/Events/Event.swift
index 507549604..b81f1c2c7 100644
--- a/Sources/Testing/Events/Event.swift
+++ b/Sources/Testing/Events/Event.swift
@@ -303,26 +303,6 @@ extension Event {
   }
 }
 
-extension Configuration.EventHandlingOptions {
-  /// Determine whether the specified event should be handled according to the
-  /// options in this instance.
-  ///
-  /// - Parameters:
-  ///   - event: The event to consider handling.
-  ///
-  /// - Returns: Whether or not the event should be handled or suppressed.
-  fileprivate func shouldHandleEvent(_ event: borrowing Event) -> Bool {
-    switch event.kind {
-    case let .issueRecorded(issue):
-      issue.severity > .warning || isWarningIssueRecordedEventEnabled
-    case .expectationChecked:
-      isExpectationCheckedEventEnabled
-    default:
-      true
-    }
-  }
-}
-
 #if !SWT_NO_SNAPSHOT_TYPES
 // MARK: - Snapshotting
 
diff --git a/Sources/Testing/Running/Configuration+EventHandling.swift b/Sources/Testing/Running/Configuration+EventHandling.swift
index 025f07d2c..e3c189f8b 100644
--- a/Sources/Testing/Running/Configuration+EventHandling.swift
+++ b/Sources/Testing/Running/Configuration+EventHandling.swift
@@ -38,3 +38,23 @@ extension Configuration {
     return eventHandler(event, contextCopy)
   }
 }
+
+extension Configuration.EventHandlingOptions {
+  /// Determine whether the specified event should be handled according to the
+  /// options in this instance.
+  ///
+  /// - Parameters:
+  ///   - event: The event to consider handling.
+  ///
+  /// - Returns: Whether or not the event should be handled or suppressed.
+  func shouldHandleEvent(_ event: borrowing Event) -> Bool {
+    switch event.kind {
+    case let .issueRecorded(issue):
+      issue.severity > .warning || isWarningIssueRecordedEventEnabled
+    case .expectationChecked:
+      isExpectationCheckedEventEnabled
+    default:
+      true
+    }
+  }
+}
diff --git a/Sources/Testing/Running/Configuration.swift b/Sources/Testing/Running/Configuration.swift
index 868cb16a2..635749b6c 100644
--- a/Sources/Testing/Running/Configuration.swift
+++ b/Sources/Testing/Running/Configuration.swift
@@ -203,9 +203,6 @@ public struct Configuration: Sendable {
 
   /// The options to use when delivering events to this configuration's event
   /// handler.
-  ///
-  /// The default value of this property is an instance of ``EventHandlingOptions-swift.struct``
-  /// with its properties initialized to their default values.
   public var eventHandlingOptions: EventHandlingOptions = .init()
 
   /// The event handler to which events should be passed when they occur.
diff --git a/Tests/TestingTests/ConfigurationTests.swift b/Tests/TestingTests/ConfigurationTests.swift
new file mode 100644
index 000000000..a735d8ac5
--- /dev/null
+++ b/Tests/TestingTests/ConfigurationTests.swift
@@ -0,0 +1,25 @@
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for Swift project authors
+//
+
+@_spi(ForToolsIntegrationOnly) import Testing
+
+@Suite("Configuration Tests")
+struct ConfigurationTests {
+  @Test
+  @available(*, deprecated, message: "Testing a deprecated SPI.")
+  func deliverExpectationCheckedEventsProperty() throws {
+    var configuration = Configuration()
+    #expect(!configuration.deliverExpectationCheckedEvents)
+    #expect(!configuration.eventHandlingOptions.isExpectationCheckedEventEnabled)
+
+    configuration.deliverExpectationCheckedEvents = true
+    #expect(configuration.eventHandlingOptions.isExpectationCheckedEventEnabled)
+  }
+}
diff --git a/Tests/TestingTests/EntryPointTests.swift b/Tests/TestingTests/EntryPointTests.swift
index fb77643f7..eae7d4b7e 100644
--- a/Tests/TestingTests/EntryPointTests.swift
+++ b/Tests/TestingTests/EntryPointTests.swift
@@ -69,7 +69,6 @@ struct EntryPointTests {
     }
     #expect(exitCode == EXIT_SUCCESS)
   }
-
 }
 
 // MARK: - Fixtures

From 1e6e866dba2ea591dc7c0089c6302ec42e80971e Mon Sep 17 00:00:00 2001
From: Stuart Montgomery <smontgomery@apple.com>
Date: Fri, 7 Feb 2025 15:01:38 -0600
Subject: [PATCH 27/32] Don't use warning symbol for test and run ended events,
 only for issue recorded events (for warning issues)

---
 .../Event.HumanReadableOutputRecorder.swift        | 14 --------------
 1 file changed, 14 deletions(-)

diff --git a/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift b/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift
index cdb877398..704ee78bb 100644
--- a/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift
+++ b/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift
@@ -373,13 +373,6 @@ extension Event.HumanReadableOutputRecorder {
             stringValue: "\(_capitalizedTitle(for: test)) \(testName) failed after \(duration)\(issues.description)."
           )
         ) + _formattedComments(for: test)
-      } else if issues.warningIssueCount > 0 {
-        [
-          Message(
-           symbol: .warning,
-           stringValue: "\(_capitalizedTitle(for: test)) \(testName) passed after \(duration)\(issues.description)."
-         )
-       ]
       } else {
         [
           Message(
@@ -529,13 +522,6 @@ extension Event.HumanReadableOutputRecorder {
             stringValue: "Test run with \(testCount.counting("test")) failed after \(duration)\(issues.description)."
           )
         ]
-      } else if issues.warningIssueCount > 0 {
-        [
-          Message(
-            symbol: .warning,
-            stringValue: "Test run with \(testCount.counting("test")) passed after \(duration)\(issues.description)."
-          )
-        ]
       } else {
         [
           Message(

From 95d83ffe9a34d40efd20d5fa006f8bd403bf5861 Mon Sep 17 00:00:00 2001
From: Stuart Montgomery <smontgomery@apple.com>
Date: Fri, 7 Feb 2025 15:43:48 -0600
Subject: [PATCH 28/32] Move pending ABI changes writeup to a separate file

---
 Documentation/ABI/JSON.md          |  9 ---------
 Documentation/ABI/Pending-ABIv1.md | 20 ++++++++++++++++++++
 2 files changed, 20 insertions(+), 9 deletions(-)
 create mode 100644 Documentation/ABI/Pending-ABIv1.md

diff --git a/Documentation/ABI/JSON.md b/Documentation/ABI/JSON.md
index 44053ff2c..2fcf4b268 100644
--- a/Documentation/ABI/JSON.md
+++ b/Documentation/ABI/JSON.md
@@ -220,12 +220,3 @@ sufficient information to display the event in a human-readable format.
   ["testID": <test-id>,
     ["testCase": <test-case>]]
 -->
-
-## Version history
-
-- Version 1 (unreleased)
-  - Introduced issue severity, with a new "warning" severity level which is
-    lower than the default "error" level. Clients upgrading from v0 should
-    begin consulting the severity of recorded issues to determine whether the
-    associated test should be marked as failing.
-- Version 0 (Initial ABI version)
diff --git a/Documentation/ABI/Pending-ABIv1.md b/Documentation/ABI/Pending-ABIv1.md
new file mode 100644
index 000000000..e1013f313
--- /dev/null
+++ b/Documentation/ABI/Pending-ABIv1.md
@@ -0,0 +1,20 @@
+# Pending ABIv1 Changes
+
+This document collects changes which have been made and are anticipated to be
+released in a future ABI/event stream version, but are still pending.
+
+> [!IMPORTANT]
+> This file describes changes which are unreleased, and are subject to change.
+> Do not depend on this version or make assumptions that these changes will
+> remain part of this ABI version.
+
+## Issue severity and warning issues.
+
+Introduced a notion of "severity" for issues, and a new "warning" severity level
+which is lower than the default "error" level. Clients upgrading from v0 should
+begin consulting the severity of recorded issues to determine whether the
+associated test should be marked as failing.
+
+### See Also
+
+- https://github.com/swiftlang/swift-testing/pull/931

From c23a4d68f81faa649a00df28def9ecc3c52da141 Mon Sep 17 00:00:00 2001
From: Stuart Montgomery <smontgomery@apple.com>
Date: Fri, 7 Feb 2025 16:15:01 -0600
Subject: [PATCH 29/32] Adjust symbols and ABI documentation

---
 Documentation/ABI/JSON.md                     |  6 -----
 Documentation/ABI/Pending-ABIv1.md            |  2 +-
 .../ABI/v0/Encoded/ABIv0.EncodedMessage.swift |  9 ++++---
 .../Event.ConsoleOutputRecorder.swift         |  6 +++--
 .../Event.HumanReadableOutputRecorder.swift   |  2 +-
 .../Events/Recorder/Event.Symbol.swift        | 24 +++++++++++++------
 6 files changed, 29 insertions(+), 20 deletions(-)

diff --git a/Documentation/ABI/JSON.md b/Documentation/ABI/JSON.md
index 2fcf4b268..23dd5b1dc 100644
--- a/Documentation/ABI/JSON.md
+++ b/Documentation/ABI/JSON.md
@@ -210,12 +210,6 @@ sufficient information to display the event in a human-readable format.
   "fail" | "difference" | "warning" | "details"
 ```
 
-<!--
-  TODO: Publicize issue severity.
-<issue-severity> ::= "warning" | "error" ; additional severity levels may be
-                                         ; added in the future
--->
-
 <!--
   ["testID": <test-id>,
     ["testCase": <test-case>]]
diff --git a/Documentation/ABI/Pending-ABIv1.md b/Documentation/ABI/Pending-ABIv1.md
index e1013f313..295696305 100644
--- a/Documentation/ABI/Pending-ABIv1.md
+++ b/Documentation/ABI/Pending-ABIv1.md
@@ -8,7 +8,7 @@ released in a future ABI/event stream version, but are still pending.
 > Do not depend on this version or make assumptions that these changes will
 > remain part of this ABI version.
 
-## Issue severity and warning issues.
+## Issue severity and warning issues
 
 Introduced a notion of "severity" for issues, and a new "warning" severity level
 which is lower than the default "error" level. Clients upgrading from v0 should
diff --git a/Sources/Testing/ABI/v0/Encoded/ABIv0.EncodedMessage.swift b/Sources/Testing/ABI/v0/Encoded/ABIv0.EncodedMessage.swift
index 5cfbf647c..874460b8f 100644
--- a/Sources/Testing/ABI/v0/Encoded/ABIv0.EncodedMessage.swift
+++ b/Sources/Testing/ABI/v0/Encoded/ABIv0.EncodedMessage.swift
@@ -25,7 +25,8 @@ extension ABIv0 {
       case `default`
       case skip
       case pass
-      case passWithKnownIssue
+      case passWithWarning
+      case passWithKnownIssue = "_passWithKnownIssue"
       case fail
       case difference
       case warning
@@ -38,8 +39,10 @@ extension ABIv0 {
           .default
         case .skip:
           .skip
-        case let .pass(knownIssueCount):
-          if knownIssueCount > 0 {
+        case let .pass(warningIssueCount, knownIssueCount):
+          if warningIssueCount > 0 {
+            .passWithWarning
+          } else if knownIssueCount > 0 {
             .passWithKnownIssue
           } else {
             .pass
diff --git a/Sources/Testing/Events/Recorder/Event.ConsoleOutputRecorder.swift b/Sources/Testing/Events/Recorder/Event.ConsoleOutputRecorder.swift
index cce3a732c..4d60a1b99 100644
--- a/Sources/Testing/Events/Recorder/Event.ConsoleOutputRecorder.swift
+++ b/Sources/Testing/Events/Recorder/Event.ConsoleOutputRecorder.swift
@@ -157,8 +157,10 @@ extension Event.Symbol {
       switch self {
       case .default, .skip, .difference:
         return "\(_ansiEscapeCodePrefix)90m\(symbolCharacter)\(_resetANSIEscapeCode)"
-      case let .pass(knownIssueCount):
-        if knownIssueCount > 0 {
+      case let .pass(warningIssueCount, knownIssueCount):
+        if warningIssueCount > 0 {
+          return "\(_ansiEscapeCodePrefix)93m\(symbolCharacter)\(_resetANSIEscapeCode)"
+        } else if knownIssueCount > 0 {
           return "\(_ansiEscapeCodePrefix)90m\(symbolCharacter)\(_resetANSIEscapeCode)"
         }
         return "\(_ansiEscapeCodePrefix)92m\(symbolCharacter)\(_resetANSIEscapeCode)"
diff --git a/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift b/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift
index 704ee78bb..b7400ab69 100644
--- a/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift
+++ b/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift
@@ -418,7 +418,7 @@ extension Event.HumanReadableOutputRecorder {
       } else {
         switch issue.severity {
         case .warning:
-          symbol = .warning
+          symbol = .pass(warningIssueCount: 1)
           subject = "a warning"
         case .error:
           symbol = .fail
diff --git a/Sources/Testing/Events/Recorder/Event.Symbol.swift b/Sources/Testing/Events/Recorder/Event.Symbol.swift
index 40bb05d40..902d1635e 100644
--- a/Sources/Testing/Events/Recorder/Event.Symbol.swift
+++ b/Sources/Testing/Events/Recorder/Event.Symbol.swift
@@ -22,9 +22,11 @@ extension Event {
     /// The symbol to use when a test passes.
     ///
     /// - Parameters:
+    ///   - warningIssueCount: The number of warnings recorded for the test.
+    ///     The default value is `0`.
     ///   - knownIssueCount: The number of known issues recorded for the test.
     ///     The default value is `0`.
-    case pass(knownIssueCount: Int = 0)
+    case pass(warningIssueCount: Int = 0, knownIssueCount: Int = 0)
 
     /// The symbol to use when a test fails.
     case fail
@@ -56,8 +58,10 @@ extension Event.Symbol {
       ("\u{1007C8}", "diamond")
     case .skip:
       ("\u{10065F}", "arrow.triangle.turn.up.right.diamond.fill")
-    case let .pass(knownIssueCount):
-      if knownIssueCount > 0 {
+    case let .pass(warningIssueCount, knownIssueCount):
+      if warningIssueCount > 0 {
+        ("\u{100123}", "questionmark.diamond.fill")
+      } else if knownIssueCount > 0 {
         ("\u{100884}", "xmark.diamond.fill")
       } else {
         ("\u{10105B}", "checkmark.diamond.fill")
@@ -114,8 +118,11 @@ extension Event.Symbol {
     case .skip:
       // Unicode: HEAVY BALLOT X
       return "\u{2718}"
-    case let .pass(knownIssueCount):
-      if knownIssueCount > 0 {
+    case let .pass(warningIssueCount, knownIssueCount):
+      if warningIssueCount > 0 {
+        // Unicode: QUESTION MARK
+        return "\u{003F}"
+      } else if knownIssueCount > 0 {
         // Unicode: HEAVY BALLOT X
         return "\u{2718}"
       } else {
@@ -149,8 +156,11 @@ extension Event.Symbol {
     case .skip:
       // Unicode: MULTIPLICATION SIGN
       return "\u{00D7}"
-    case let .pass(knownIssueCount):
-      if knownIssueCount > 0 {
+    case let .pass(warningIssueCount, knownIssueCount):
+      if warningIssueCount > 0 {
+        // Unicode: QUESTION MARK
+        return "\u{003F}"
+      } else if knownIssueCount > 0 {
         // Unicode: MULTIPLICATION SIGN
         return "\u{00D7}"
       } else {

From 9fa497e8cd92131e11d813b630ec1e05781ee313 Mon Sep 17 00:00:00 2001
From: Stuart Montgomery <smontgomery@apple.com>
Date: Fri, 7 Feb 2025 22:25:00 -0600
Subject: [PATCH 30/32] Adjust event symbols

---
 .../ABI/v0/Encoded/ABIv0.EncodedMessage.swift | 12 +++----
 .../Event.ConsoleOutputRecorder.swift         |  8 ++---
 .../Event.HumanReadableOutputRecorder.swift   |  2 +-
 .../Events/Recorder/Event.Symbol.swift        | 36 ++++++++++---------
 4 files changed, 30 insertions(+), 28 deletions(-)

diff --git a/Sources/Testing/ABI/v0/Encoded/ABIv0.EncodedMessage.swift b/Sources/Testing/ABI/v0/Encoded/ABIv0.EncodedMessage.swift
index 874460b8f..cf44f0af0 100644
--- a/Sources/Testing/ABI/v0/Encoded/ABIv0.EncodedMessage.swift
+++ b/Sources/Testing/ABI/v0/Encoded/ABIv0.EncodedMessage.swift
@@ -25,8 +25,8 @@ extension ABIv0 {
       case `default`
       case skip
       case pass
-      case passWithWarning
-      case passWithKnownIssue = "_passWithKnownIssue"
+      case passWithWarnings = "_passWithWarnings"
+      case passWithKnownIssue
       case fail
       case difference
       case warning
@@ -39,14 +39,14 @@ extension ABIv0 {
           .default
         case .skip:
           .skip
-        case let .pass(warningIssueCount, knownIssueCount):
-          if warningIssueCount > 0 {
-            .passWithWarning
-          } else if knownIssueCount > 0 {
+        case let .pass(knownIssueCount):
+          if knownIssueCount > 0 {
             .passWithKnownIssue
           } else {
             .pass
           }
+        case .passWithWarnings:
+          .passWithWarnings
         case .fail:
           .fail
         case .difference:
diff --git a/Sources/Testing/Events/Recorder/Event.ConsoleOutputRecorder.swift b/Sources/Testing/Events/Recorder/Event.ConsoleOutputRecorder.swift
index 4d60a1b99..b375b2da1 100644
--- a/Sources/Testing/Events/Recorder/Event.ConsoleOutputRecorder.swift
+++ b/Sources/Testing/Events/Recorder/Event.ConsoleOutputRecorder.swift
@@ -157,13 +157,13 @@ extension Event.Symbol {
       switch self {
       case .default, .skip, .difference:
         return "\(_ansiEscapeCodePrefix)90m\(symbolCharacter)\(_resetANSIEscapeCode)"
-      case let .pass(warningIssueCount, knownIssueCount):
-        if warningIssueCount > 0 {
-          return "\(_ansiEscapeCodePrefix)93m\(symbolCharacter)\(_resetANSIEscapeCode)"
-        } else if knownIssueCount > 0 {
+      case let .pass(knownIssueCount):
+        if knownIssueCount > 0 {
           return "\(_ansiEscapeCodePrefix)90m\(symbolCharacter)\(_resetANSIEscapeCode)"
         }
         return "\(_ansiEscapeCodePrefix)92m\(symbolCharacter)\(_resetANSIEscapeCode)"
+      case .passWithWarnings:
+        return "\(_ansiEscapeCodePrefix)93m\(symbolCharacter)\(_resetANSIEscapeCode)"
       case .fail:
         return "\(_ansiEscapeCodePrefix)91m\(symbolCharacter)\(_resetANSIEscapeCode)"
       case .warning:
diff --git a/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift b/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift
index b7400ab69..2e40b2789 100644
--- a/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift
+++ b/Sources/Testing/Events/Recorder/Event.HumanReadableOutputRecorder.swift
@@ -418,7 +418,7 @@ extension Event.HumanReadableOutputRecorder {
       } else {
         switch issue.severity {
         case .warning:
-          symbol = .pass(warningIssueCount: 1)
+          symbol = .passWithWarnings
           subject = "a warning"
         case .error:
           symbol = .fail
diff --git a/Sources/Testing/Events/Recorder/Event.Symbol.swift b/Sources/Testing/Events/Recorder/Event.Symbol.swift
index 902d1635e..3a3f6df8e 100644
--- a/Sources/Testing/Events/Recorder/Event.Symbol.swift
+++ b/Sources/Testing/Events/Recorder/Event.Symbol.swift
@@ -22,11 +22,13 @@ extension Event {
     /// The symbol to use when a test passes.
     ///
     /// - Parameters:
-    ///   - warningIssueCount: The number of warnings recorded for the test.
-    ///     The default value is `0`.
     ///   - knownIssueCount: The number of known issues recorded for the test.
     ///     The default value is `0`.
-    case pass(warningIssueCount: Int = 0, knownIssueCount: Int = 0)
+    case pass(knownIssueCount: Int = 0)
+
+    /// The symbol to use when a test passes with one or more warnings.
+    @_spi(Experimental)
+    case passWithWarnings
 
     /// The symbol to use when a test fails.
     case fail
@@ -58,14 +60,14 @@ extension Event.Symbol {
       ("\u{1007C8}", "diamond")
     case .skip:
       ("\u{10065F}", "arrow.triangle.turn.up.right.diamond.fill")
-    case let .pass(warningIssueCount, knownIssueCount):
-      if warningIssueCount > 0 {
-        ("\u{100123}", "questionmark.diamond.fill")
-      } else if knownIssueCount > 0 {
+    case let .pass(knownIssueCount):
+      if knownIssueCount > 0 {
         ("\u{100884}", "xmark.diamond.fill")
       } else {
         ("\u{10105B}", "checkmark.diamond.fill")
       }
+    case .passWithWarnings:
+      ("\u{100123}", "questionmark.diamond.fill")
     case .fail:
       ("\u{100884}", "xmark.diamond.fill")
     case .difference:
@@ -118,17 +120,17 @@ extension Event.Symbol {
     case .skip:
       // Unicode: HEAVY BALLOT X
       return "\u{2718}"
-    case let .pass(warningIssueCount, knownIssueCount):
-      if warningIssueCount > 0 {
-        // Unicode: QUESTION MARK
-        return "\u{003F}"
-      } else if knownIssueCount > 0 {
+    case let .pass(knownIssueCount):
+      if knownIssueCount > 0 {
         // Unicode: HEAVY BALLOT X
         return "\u{2718}"
       } else {
         // Unicode: HEAVY CHECK MARK
         return "\u{2714}"
       }
+    case .passWithWarnings:
+      // Unicode: QUESTION MARK
+      return "\u{003F}"
     case .fail:
       // Unicode: HEAVY BALLOT X
       return "\u{2718}"
@@ -156,17 +158,17 @@ extension Event.Symbol {
     case .skip:
       // Unicode: MULTIPLICATION SIGN
       return "\u{00D7}"
-    case let .pass(warningIssueCount, knownIssueCount):
-      if warningIssueCount > 0 {
-        // Unicode: QUESTION MARK
-        return "\u{003F}"
-      } else if knownIssueCount > 0 {
+    case let .pass(knownIssueCount):
+      if knownIssueCount > 0 {
         // Unicode: MULTIPLICATION SIGN
         return "\u{00D7}"
       } else {
         // Unicode: SQUARE ROOT
         return "\u{221A}"
       }
+    case .passWithWarnings:
+      // Unicode: QUESTION MARK
+      return "\u{003F}"
     case .fail:
       // Unicode: MULTIPLICATION SIGN
       return "\u{00D7}"

From 57f2221fbbd520f51f222c4c11852bfc777e1d02 Mon Sep 17 00:00:00 2001
From: Stuart Montgomery <smontgomery@apple.com>
Date: Mon, 10 Feb 2025 14:52:04 -0600
Subject: [PATCH 31/32] PR feedback

---
 Documentation/ABI/Pending-ABIv1.md            | 20 -------------------
 Sources/Testing/Running/Configuration.swift   |  1 +
 .../Testing/Running/Runner.RuntimeState.swift |  3 ---
 3 files changed, 1 insertion(+), 23 deletions(-)
 delete mode 100644 Documentation/ABI/Pending-ABIv1.md

diff --git a/Documentation/ABI/Pending-ABIv1.md b/Documentation/ABI/Pending-ABIv1.md
deleted file mode 100644
index 295696305..000000000
--- a/Documentation/ABI/Pending-ABIv1.md
+++ /dev/null
@@ -1,20 +0,0 @@
-# Pending ABIv1 Changes
-
-This document collects changes which have been made and are anticipated to be
-released in a future ABI/event stream version, but are still pending.
-
-> [!IMPORTANT]
-> This file describes changes which are unreleased, and are subject to change.
-> Do not depend on this version or make assumptions that these changes will
-> remain part of this ABI version.
-
-## Issue severity and warning issues
-
-Introduced a notion of "severity" for issues, and a new "warning" severity level
-which is lower than the default "error" level. Clients upgrading from v0 should
-begin consulting the severity of recorded issues to determine whether the
-associated test should be marked as failing.
-
-### See Also
-
-- https://github.com/swiftlang/swift-testing/pull/931
diff --git a/Sources/Testing/Running/Configuration.swift b/Sources/Testing/Running/Configuration.swift
index 635749b6c..a917c2f5b 100644
--- a/Sources/Testing/Running/Configuration.swift
+++ b/Sources/Testing/Running/Configuration.swift
@@ -189,6 +189,7 @@ public struct Configuration: Sendable {
     /// handlers since this is an experimental feature.
     ///
     /// - Warning: Warning issues are not yet an approved feature.
+    @_spi(Experimental)
     public var isWarningIssueRecordedEventEnabled: Bool = false
 
     /// Whether or not events of the kind
diff --git a/Sources/Testing/Running/Runner.RuntimeState.swift b/Sources/Testing/Running/Runner.RuntimeState.swift
index 6c2764044..9ae299412 100644
--- a/Sources/Testing/Running/Runner.RuntimeState.swift
+++ b/Sources/Testing/Running/Runner.RuntimeState.swift
@@ -160,9 +160,6 @@ extension Configuration {
   /// An atomic counter that tracks the number of "current" configurations that
   /// have set ``EventHandlingOptions/isExpectationCheckedEventEnabled`` to
   /// `true`.
-  ///
-  /// On older Apple platforms, this property is not available and ``all`` is
-  /// directly consulted instead (which is less efficient.)
   private static let _deliverExpectationCheckedEventsCount = Locked(rawValue: 0)
 
   /// Whether or not events of the kind

From 4811f395890f5a2e40d506a229485c5e86776188 Mon Sep 17 00:00:00 2001
From: Stuart Montgomery <smontgomery@apple.com>
Date: Tue, 11 Feb 2025 10:04:56 -0600
Subject: [PATCH 32/32] Improve style in tests

---
 Tests/TestingTests/EventRecorderTests.swift | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/Tests/TestingTests/EventRecorderTests.swift b/Tests/TestingTests/EventRecorderTests.swift
index 2219ed54e..6b5b9bd81 100644
--- a/Tests/TestingTests/EventRecorderTests.swift
+++ b/Tests/TestingTests/EventRecorderTests.swift
@@ -183,13 +183,13 @@ struct EventRecorderTests {
   @Test(
     "Issue counts are summed correctly on test end",
     arguments: [
-      ("f()", ".* Test f\\(\\) failed after .+ seconds with 5 issues \\(including 3 known issues\\)\\."),
-      ("g()", ".* Test g\\(\\) failed after .+ seconds with 2 issues \\(including 1 known issue\\)\\."),
-      ("h()", ".* Test h\\(\\) passed after .+ seconds with 1 warning\\."),
-      ("i()", ".* Test i\\(\\) failed after .+ seconds with 2 issues \\(including 1 warning\\)\\."),
-      ("j()", ".* Test j\\(\\) passed after .+ seconds with 1 warning and 1 known issue\\."),
-      ("k()", ".* Test k\\(\\) passed after .+ seconds with 1 known issue\\."),
-      ("PredictablyFailingTests", ".* Suite PredictablyFailingTests failed after .+ seconds with 13 issues \\(including 3 warnings and 6 known issues\\)\\."),
+      ("f()", #".* Test f\(\) failed after .+ seconds with 5 issues \(including 3 known issues\)\."#),
+      ("g()", #".* Test g\(\) failed after .+ seconds with 2 issues \(including 1 known issue\)\."#),
+      ("h()", #".* Test h\(\) passed after .+ seconds with 1 warning\."#),
+      ("i()", #".* Test i\(\) failed after .+ seconds with 2 issues \(including 1 warning\)\."#),
+      ("j()", #".* Test j\(\) passed after .+ seconds with 1 warning and 1 known issue\."#),
+      ("k()", #".* Test k\(\) passed after .+ seconds with 1 known issue\."#),
+      ("PredictablyFailingTests", #".* Suite PredictablyFailingTests failed after .+ seconds with 13 issues \(including 3 warnings and 6 known issues\)\."#),
     ]
   )
   func issueCountSummingAtTestEnd(testName: String, expectedPattern: String) async throws {
@@ -210,10 +210,10 @@ struct EventRecorderTests {
     }
 
     let expectedSuffixRegex = try Regex(expectedPattern)
-    _ = try #require(buffer
+    #expect(try buffer
       .split(whereSeparator: \.isNewline)
       .compactMap(expectedSuffixRegex.wholeMatch(in:))
-      .first,
+      .first != nil,
       "buffer: \(buffer)"
     )
   }