chore: Add tests covering the version transition (#661)

Fixes #541 by failure to reproduce.

### Changes are visible to end-users: no

### Test plan

This is the test plan.

Author: arrdem

.github/workflows/ci.yaml

@@ -29,6 +29,7 @@ jobs:
       folders: |
         [
           "e2e/cross-repo-610",
+          "e2e/interpreter-version-541",
           "e2e/repository-rule-deps",
           "e2e/smoke",
           "e2e/system-interpreter",
@@ -41,6 +42,7 @@ jobs:
         [
           {"os": "windows-latest"},
           {"folder": "e2e/cross-repo-610", "bzlmodEnabled": false},
+          {"folder": "e2e/interpreter-version-541", "bzlmodEnabled": false},
           {"folder": "e2e/repository-rule-deps", "bzlmodEnabled": false},
           {"folder": "e2e/system-interpreter", "bzlmodEnabled": false},
           {"folder": "examples/uv_pip_compile", "bzlmodEnabled": false},

e2e/interpreter-version-541/BUILD.bazel

@@ -0,0 +1,43 @@
+load("@aspect_bazel_lib//lib:expand_template.bzl", "expand_template")
+load("@aspect_rules_py//py:defs.bzl", "py_test")
+load("@aspect_rules_py//py/unstable:defs.bzl", "py_venv_test")
+
+[
+    [
+        expand_template(
+            name = "expanded_test_{}.py".format(ver.replace(".", "_")),
+            out = "test_{}.py".format(ver.replace(".", "_")),
+            substitutions = {
+                "<VERSION>": ver,
+            },
+            template = "test.py",
+        ),
+        py_venv_test(
+            name = "test_{}_venv".format(ver.replace(".", "_")),
+            srcs = [
+                "expanded_test_{}.py".format(ver.replace(".", "_")),
+            ],
+            imports = [
+                ".",
+            ],
+            main = "expanded_test_{}.py".format(ver.replace(".", "_")),
+            python_version = ver,
+        ),
+        py_test(
+            name = "test_{}_classic".format(ver.replace(".", "_")),
+            srcs = [
+                "expanded_test_{}.py".format(ver.replace(".", "_")),
+            ],
+            imports = [
+                ".",
+            ],
+            main = "expanded_test_{}.py".format(ver.replace(".", "_")),
+            python_version = ver,
+        ),
+    ]
+    for ver in [
+        "3.11",
+        "3.12",
+        "3.13",
+    ]
+]

e2e/interpreter-version-541/MODULE.bazel

@@ -0,0 +1,22 @@
+"Bazel dependencies"
+
+bazel_dep(name = "aspect_rules_py", version = "0.0.0", dev_dependency = True)
+local_path_override(
+    module_name = "aspect_rules_py",
+    path = "../..",
+)
+
+bazel_dep(name = "aspect_bazel_lib", version = "2.16.0")
+
+bazel_dep(name = "rules_python", version = "1.6.3", dev_dependency = True)
+
+python = use_extension("@rules_python//python/extensions:python.bzl", "python")
+python.toolchain(
+    python_version = "3.11",
+)
+python.toolchain(
+    python_version = "3.12",
+)
+python.toolchain(
+    python_version = "3.13",
+)

e2e/interpreter-version-541/test.py

@@ -0,0 +1,21 @@
+#!/usr/bin/env python3
+
+import sys
+import site
+
+print("---")
+print("__file__:", __file__)
+print("sys.prefix:", sys.prefix)
+print("sys.executable:", sys.executable)
+print("site.PREFIXES:")
+for p in site.PREFIXES:
+    print(" -", p)
+
+# The virtualenv module should have already been loaded at interpreter startup
+assert "_virtualenv" in sys.modules
+
+# Assert that we booted against the expected interpreter version
+EXPECTED_VERSION = "<VERSION>"
+print(repr(EXPECTED_VERSION))
+print(repr(sys.version))
+assert sys.version.startswith(EXPECTED_VERSION)