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Update the messaging around the use of deinit for teardown #551

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Update the messaging around the use of deinit for teardown #551

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cd0a058
Update the messaging around the use of deinit for teardown
medreisbach Jul 18, 2024
e1ae848
Remove "quick" from deinit.
medreisbach Jul 18, 2024
21923ea
Update Sources/Testing/Testing.docc/MigratingFromXCTest.md
medreisbach Jul 19, 2024
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18 changes: 11 additions & 7 deletions Sources/Testing/Testing.docc/MigratingFromXCTest.md
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Expand Up @@ -94,11 +94,11 @@ For more information about suites and how to declare and customize them, see

### Convert setup and teardown functions

In XCTest, code can be scheduled to run before and after a test using the
In XCTest, you can schedule code to run before a test using the
[`setUp()`](https://developer.apple.com/documentation/xctest/xctest/3856481-setup)
and [`tearDown()`](https://developer.apple.com/documentation/xctest/xctest/3856482-teardown)
family of functions. When writing tests using the testing library, implement
`init()` and/or `deinit` instead:
family of functions. When writing tests using the testing library, you can use
`init()` for setup. Your suite's initializer can be `async`, `throwing`, or
actor-isolated if necessary.

@Row {
@Column {
Expand Down Expand Up @@ -127,9 +127,13 @@ family of functions. When writing tests using the testing library, implement
}
}

The use of `async` and `throws` is optional. If teardown is needed, declare your
test suite as a `final` class or as an actor rather than as a structure and
implement `deinit`:
In XCTest, you can also schedule work to run after a test using the [`tearDown()`](https://developer.apple.com/documentation/xctest/xctest/3856482-teardown)
family of functions. When writing tests using the testing library, adopt structured
[concurrency](https://docs.swift.org/swift-book/documentation/the-swift-programming-language/concurrency/)
and take advantage of Swift to handle cleanup for you where possible rather
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Can you clarify what feature(s) of Swift concurrency, or which APIs, you mean here which assist with cleanup? I can think of defer, but I would consider that a basic language feature rather than a concurrency feature.

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I think what we should aim to push people towards is using with style methods e.g. try await withNetworkConnection { connection in ... }. This is the pattern that recommend to people to have guaranteed lifetimes with structured concurrency.

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That's something they have to write themselves, and explaining how to write one would get us into the weeds a bit.

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There is precedent for describing how testing helps you design nicer APIs and vice versa, and it's something Apple has already published in the Xcode documentation: https://developer.apple.com/documentation/xcode/updating-your-existing-codebase-to-accommodate-unit-tests

So maybe we could take a similar approach here, where we show a with… function as an example of designing API+test together, but (as a separate task) create another doc that shows the thinking behind that design?

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Would this be an appropriate place to use a snippet?

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I think an example here would be extremely helpful for users trying to migrate

than relying on a dedicated teardown method. If teardown is necessary, declare
your test suite as a class or actor, and implement `deinit` with operations
that are synchronous and non-throwing.

@Row {
@Column {
Expand Down