Revert to running tests from from a temp dir when test-sources is unset (#2420)

* Revert to running tests from from a temp dir when test-sources is unset

* Fix placeholders error message, add test for it

* Add back {project} placeholders to CIBW_TEST_COMMAND in tests & docs

* Update test/test_before_test.py

---------

Co-authored-by: Henry Schreiner <HenrySchreinerIII@gmail.com>

cibuildwheel/platforms/ios.py

@@ -559,19 +559,19 @@ def build(options: Options, tmp_path: Path) -> None:
                         env=test_env,
                     )
 
-                    if not build_options.test_sources:
+                    testbed_app_path = testbed_path / "iOSTestbed" / "app"
-                        # iOS requires an explicit test-sources, as the project directory
-                        # isn't visible on the simulator.
-
-                        msg = "Testing on iOS requires a definition of test-sources."
-                        raise errors.FatalError(msg)
 
                     # Copy the test sources to the testbed app
-                    copy_test_sources(
+                    if build_options.test_sources:
-                        build_options.test_sources,
+                        copy_test_sources(
-                        build_options.package_dir,
+                            build_options.test_sources,
-                        testbed_path / "iOSTestbed" / "app",
+                            build_options.package_dir,
-                    )
+                            testbed_app_path,
+                        )
+                    else:
+                        (testbed_app_path / "test_fail.py").write_text(
+                            resources.TEST_FAIL_CWD_FILE.read_text()
+                        )
 
                     log.step("Installing test requirements...")
                     # Install the compiled wheel (with any test extras), plus
@@ -598,6 +598,26 @@ def build(options: Options, tmp_path: Path) -> None:
 
                     log.step("Running test suite...")
 
+                    # iOS doesn't support placeholders in the test command,
+                    # because the source dir isn't visible on the simulator.
+                    if (
+                        "{project}" in build_options.test_command
+                        or "{package}" in build_options.test_command
+                    ):
+                        msg = unwrap_preserving_paragraphs(
+                            f"""
+                            iOS tests configured with a test command that uses the "{{project}}" or
+                            "{{package}}" placeholder. iOS tests cannot use placeholders, because the
+                            source directory is not visible on the simulator.
+
+                            In addition, iOS tests must run as a Python module, so the test command
+                            must begin with 'python -m'.
+
+                            Test command: {build_options.test_command!r}
+                            """
+                        )
+                        raise errors.FatalError(msg)
+
                     test_command_parts = shlex.split(build_options.test_command)
                     if test_command_parts[0:2] != ["python", "-m"]:
                         first_part = test_command_parts[0]

cibuildwheel/platforms/linux.py

@@ -398,9 +398,10 @@ def build_in_container(
                 wheel=wheel_to_test,
             )
 
+            test_cwd = testing_temp_dir / "test_cwd"
+            container.call(["mkdir", "-p", test_cwd])
+
             if build_options.test_sources:
-                test_cwd = testing_temp_dir / "test_cwd"
-                container.call(["mkdir", "-p", test_cwd])
                 copy_test_sources(
                     build_options.test_sources,
                     build_options.package_dir,
@@ -408,8 +409,9 @@ def build_in_container(
                     copy_into=container.copy_into,
                 )
             else:
-                # There are no test sources. Run the tests in the project directory.
+                # Use the test_fail.py file to raise a nice error if the user
-                test_cwd = PurePosixPath(container_project_path)
+                # tries to run tests in the cwd
+                container.copy_into(resources.TEST_FAIL_CWD_FILE, test_cwd / "test_fail.py")
 
             container.call(["sh", "-c", test_command_prepared], cwd=test_cwd, env=virtualenv_env)
 

cibuildwheel/platforms/macos.py

@@ -706,8 +706,9 @@ def build(options: Options, tmp_path: Path) -> None:
                         wheel=repaired_wheel,
                     )
 
+                    test_cwd = identifier_tmp_dir / "test_cwd"
+
                     if build_options.test_sources:
-                        test_cwd = identifier_tmp_dir / "test_cwd"
                         # only create test_cwd if it doesn't already exist - it
                         # may have been created during a previous `testing_arch`
                         if not test_cwd.exists():
@@ -718,8 +719,12 @@ def build(options: Options, tmp_path: Path) -> None:
                                 test_cwd,
                             )
                     else:
-                        # There are no test sources. Run the tests in the project directory.
+                        # Use the test_fail.py file to raise a nice error if the user
-                        test_cwd = Path.cwd()
+                        # tries to run tests in the cwd
+                        test_cwd.mkdir(exist_ok=True)
+                        (test_cwd / "test_fail.py").write_text(
+                            resources.TEST_FAIL_CWD_FILE.read_text()
+                        )
 
                     shell_with_arch(test_command_prepared, cwd=test_cwd, env=virtualenv_env)
 

cibuildwheel/platforms/pyodide.py

@@ -523,17 +523,19 @@ def build(options: Options, tmp_path: Path) -> None:
                     package=build_options.package_dir.resolve(),
                 )
 
+                test_cwd = identifier_tmp_dir / "test_cwd"
+                test_cwd.mkdir(exist_ok=True)
+
                 if build_options.test_sources:
-                    test_cwd = identifier_tmp_dir / "test_cwd"
-                    test_cwd.mkdir(exist_ok=True)
                     copy_test_sources(
                         build_options.test_sources,
                         build_options.package_dir,
                         test_cwd,
                     )
                 else:
-                    # There are no test sources. Run the tests in the project directory.
+                    # Use the test_fail.py file to raise a nice error if the user
-                    test_cwd = Path.cwd()
+                    # tries to run tests in the cwd
+                    (test_cwd / "test_fail.py").write_text(resources.TEST_FAIL_CWD_FILE.read_text())
 
                 shell(test_command_prepared, cwd=test_cwd, env=virtualenv_env)
 

cibuildwheel/platforms/windows.py

@@ -588,24 +588,26 @@ def build(options: Options, tmp_path: Path) -> None:
                 # run the tests from a temp dir, with an absolute path in the command
                 # (this ensures that Python runs the tests against the installed wheel
                 # and not the repo code)
-                test_command_prepared = prepare_command(
+                test_cwd = identifier_tmp_dir / "test_cwd"
-                    build_options.test_command,
+                test_cwd.mkdir()
-                    project=Path.cwd(),
+
-                    package=options.globals.package_dir.resolve(),
-                    wheel=repaired_wheel,
-                )
                 if build_options.test_sources:
-                    test_cwd = identifier_tmp_dir / "test_cwd"
-                    test_cwd.mkdir()
                     copy_test_sources(
                         build_options.test_sources,
                         build_options.package_dir,
                         test_cwd,
                     )
                 else:
-                    # There are no test sources. Run the tests in the project directory.
+                    # Use the test_fail.py file to raise a nice error if the user
-                    test_cwd = Path.cwd()
+                    # tries to run tests in the cwd
+                    (test_cwd / "test_fail.py").write_text(resources.TEST_FAIL_CWD_FILE.read_text())
 
+                test_command_prepared = prepare_command(
+                    build_options.test_command,
+                    project=Path.cwd(),
+                    package=options.globals.package_dir.resolve(),
+                    wheel=repaired_wheel,
+                )
                 shell(test_command_prepared, cwd=test_cwd, env=virtualenv_env)
 
             # we're all done here; move it to output (remove if already exists)

cibuildwheel/resources/testing_temp_dir_file.py

@@ -0,0 +1,36 @@
+# this file is copied to the testing cwd, to raise the below error message if
+# pytest/unittest is run from there.
+
+import sys
+import unittest
+from typing import NoReturn
+
+
+class TestStringMethods(unittest.TestCase):
+    def test_fail(self) -> NoReturn:
+        if sys.platform == "ios":
+            msg = (
+                "You tried to run tests from the testbed app's working "
+                "directory, without specifying `test-sources`. "
+                "On iOS, you must copy your test files to the testbed app by "
+                "setting the `test-sources` option in your cibuildwheel "
+                "configuration."
+            )
+        else:
+            msg = (
+                "cibuildwheel executes tests from a different working directory to "
+                "your project. This ensures only your wheel is imported, preventing "
+                "Python from accessing files that haven't been packaged into the "
+                "wheel. "
+                "\n\n"
+                "Please specify a path to your tests when invoking pytest "
+                "using the {project} placeholder, e.g. `pytest {project}` or "
+                "`pytest {project}/tests`. cibuildwheel will replace {project} with "
+                "the path to your project. "
+                "\n\n"
+                "Alternatively, you can specify your test files using the "
+                "`test-sources` option, and cibuildwheel will copy them to the "
+                "working directory for testing."
+            )
+
+        self.fail(msg)

cibuildwheel/util/resources.py

@@ -17,6 +17,7 @@ CONSTRAINTS: Final[Path] = PATH / "constraints.txt"
 VIRTUALENV: Final[Path] = PATH / "virtualenv.toml"
 CIBUILDWHEEL_SCHEMA: Final[Path] = PATH / "cibuildwheel.schema.json"
 PYTHON_BUILD_STANDALONE_RELEASES: Final[Path] = PATH / "python-build-standalone-releases.json"
+TEST_FAIL_CWD_FILE: Final[Path] = PATH / "testing_temp_dir_file.py"
 
 
 # this value is cached because it's used a lot in unit tests

docs/configuration.md

@@ -17,7 +17,7 @@ cibuildwheel to run tests, add the following YAML to your CI config file:
     ```yaml
     env:
       CIBW_TEST_REQUIRES: pytest
-      CIBW_TEST_COMMAND: "pytest ./tests"
+      CIBW_TEST_COMMAND: "pytest {project}/tests"
     ```
 
 !!! tab "Azure Pipelines"
@@ -27,7 +27,7 @@ cibuildwheel to run tests, add the following YAML to your CI config file:
     ```yaml
     variables:
       CIBW_TEST_REQUIRES: pytest
-      CIBW_TEST_COMMAND: "pytest ./tests"
+      CIBW_TEST_COMMAND: "pytest {project}/tests"
     ```
 
 !!! tab "Travis CI"
@@ -38,18 +38,7 @@ cibuildwheel to run tests, add the following YAML to your CI config file:
     env:
       global:
         - CIBW_TEST_REQUIRES=pytest
-        - CIBW_TEST_COMMAND="pytest ./tests"
+        - CIBW_TEST_COMMAND="pytest {project}/tests"
-    ```
-
-!!! tab "AppVeyor"
-
-    > appveyor.yml ([docs](https://www.appveyor.com/docs/build-configuration/#environment-variables))
-
-    ```yaml
-    environment:
-      global:
-        CIBW_TEST_REQUIRES: pytest
-        CIBW_TEST_COMMAND: "pytest {project}\\tests"
     ```
 
 !!! tab "CircleCI"
@@ -61,7 +50,7 @@ cibuildwheel to run tests, add the following YAML to your CI config file:
       job_name:
         environment:
           CIBW_TEST_REQUIRES: pytest
-          CIBW_TEST_COMMAND: "pytest ./tests"
+          CIBW_TEST_COMMAND: "pytest {project}/tests"
     ```
 
 !!! tab "Gitlab CI"
@@ -72,7 +61,7 @@ cibuildwheel to run tests, add the following YAML to your CI config file:
     linux:
       variables:
         CIBW_TEST_REQUIRES: pytest
-        CIBW_TEST_COMMAND: "pytest ./tests"
+        CIBW_TEST_COMMAND: "pytest {project}/tests"
     ```
 
 !!! tab "Cirrus CI"
@@ -82,7 +71,7 @@ cibuildwheel to run tests, add the following YAML to your CI config file:
     ```yaml
     env:
       CIBW_TEST_REQUIRES: pytest
-      CIBW_TEST_COMMAND: "pytest ./tests"
+      CIBW_TEST_COMMAND: "pytest {project}/tests"
     ```
 
 ## Configuration file {: #configuration-file}

docs/options.md

@@ -28,7 +28,7 @@ This option can also be set using the [command-line option](#command-line) `--pl
 
     ```bash
     export CIBW_BUILD='cp37-*'
-    export CIBW_TEST_COMMAND='pytest ./tests'
+    export CIBW_TEST_COMMAND='pytest {project}/tests'
     cibuildwheel --platform linux .
     ```
 
@@ -1284,23 +1284,23 @@ Shell command to run tests after the build. The wheel will be installed
 automatically and available for import from the tests. If this variable is not
 set, your wheel will not be installed after building.
 
-By default, tests are executed from your project directory. When specifying
+To ensure the wheel is imported by your tests (instead of your source copy),
-`test-command`, you can optionally use the placeholders `{package}` and
+**Tests are executed from a temporary directory**, outside of your source
-`{project}` to pass in the location of your test code:
+tree. To access your test code, you have a couple of options:
 
-- `{package}` is the path to the package being built - the `package_dir`
+- You can use the [`test-sources`](#test-sources) setting to copy specific
-  argument supplied to cibuildwheel on the command line.
+  files from your source tree into the temporary directory. When using
-- `{project}` is an absolute path to the project root - the working directory
+  test-sources, use relative paths in your test command, as if they were
-  where cibuildwheel was called.
+  relative to the project root.
 
-Using `{package}` or `{project}` used to be required, but since cibuildwheel
+- You can use the `{package}` or `{project}` placeholders in your
-3.0, tests are run from the project root by default. This means that you can
+  `test-command` to refer to the package being built or the project root,
-use relative paths in your test command, and they will be relative to the
+  respectively.
-project root.
 
-Alternatively, you can use the [`test-sources`](#test-sources) setting to
+    - `{package}` is the path to the package being built - the `package_dir`
-create a temporary folder populated with a specific subset of project files to
+      argument supplied to cibuildwheel on the command line.
-run your test suite.
+    - `{project}` is an absolute path to the project root - the working
+      directory where cibuildwheel was called.
 
 On all platforms other than iOS, the command is run in a shell, so you can write things like `cmd1 && cmd2`.
 
@@ -1318,18 +1318,18 @@ Platform-specific environment variables are also available:<br/>
     ```toml
     [tool.cibuildwheel]
     # Run the package tests using `pytest`
-    test-command = "pytest ./tests"
+    test-command = "pytest {project}/tests"
 
     # Trigger an install of the package, but run nothing of note
     test-command = "echo Wheel installed"
 
     # Multiline example
     test-command = [
-      "pytest ./tests",
+      "pytest {project}/tests",
-      "python ./test.py",
+      "python {project}/test.py",
     ]
 
-    # run tests on ios
+    # run tests on ios - when test-sources is set, use relative paths, not {project} or {package}
     [tool.cibuildwheel.ios]
     test-sources = ["tests"]
     test-command = "python -m pytest ./tests"
@@ -1341,17 +1341,17 @@ Platform-specific environment variables are also available:<br/>
 
     ```yaml
     # Run the package tests using `pytest`
-    CIBW_TEST_COMMAND: pytest ./tests
+    CIBW_TEST_COMMAND: pytest {project}/tests
 
     # Trigger an install of the package, but run nothing of note
     CIBW_TEST_COMMAND: "echo Wheel installed"
 
     # Multi-line example - join with && on all platforms
     CIBW_TEST_COMMAND: >
-      pytest ./tests &&
+      pytest {project}/tests &&
-      python ./test.py
+      python {project}/test.py
 
-    # run tests on ios
+    # run tests on ios - when test-sources is set, use relative paths, not {project} or {package}
     CIBW_TEST_SOURCES_IOS: tests
     CIBW_TEST_COMMAND_IOS: python -m pytest ./tests
     ```

test/test_abi_variants.py

@@ -187,7 +187,7 @@ def test_abi_none(tmp_path, capfd):
         project_dir,
         add_env={
             "CIBW_TEST_REQUIRES": "pytest",
-            "CIBW_TEST_COMMAND": f"{utils.invoke_pytest()} ./test",
+            "CIBW_TEST_COMMAND": f"{utils.invoke_pytest()} {{project}}/test",
             # limit the number of builds for test performance reasons
             "CIBW_BUILD": "cp38-* cp{}{}-* cp313t-* pp310-*".format(*utils.SINGLE_PYTHON_VERSION),
             "CIBW_ENABLE": "all",

test/test_before_test.py

@@ -62,10 +62,10 @@ def test(tmp_path, build_frontend_env):
             "CIBW_TEST_REQUIRES": "pytest",
             # the 'false ||' bit is to ensure this command runs in a shell on
             # mac/linux.
-            "CIBW_TEST_COMMAND": f"false || {utils.invoke_pytest()} ./test",
+            "CIBW_TEST_COMMAND": f"false || {utils.invoke_pytest()} {{project}}/test",
             # pytest fails on GraalPy 24.2.0 on Windows so we skip it there
             # until https://github.com/oracle/graalpython/issues/490 is fixed
-            "CIBW_TEST_COMMAND_WINDOWS": "where graalpy || pytest ./test",
+            "CIBW_TEST_COMMAND_WINDOWS": "where graalpy || pytest {project}/test",
             **build_frontend_env,
         },
     )

test/test_emulation.py

@@ -32,7 +32,7 @@ def test(tmp_path, request):
         project_dir,
         add_env={
             "CIBW_TEST_REQUIRES": "pytest",
-            "CIBW_TEST_COMMAND": "pytest ./test",
+            "CIBW_TEST_COMMAND": "pytest {project}/test",
             "CIBW_ARCHS": archs,
             # TODO remove me once proper support is added
             "CIBW_MANYLINUX_RISCV64_IMAGE": "ghcr.io/mayeut/manylinux_2_35:2025.05.11-1",

test/test_ios.py

@@ -91,8 +91,9 @@ def test_ios_platforms(tmp_path, build_config, monkeypatch, capfd):
     assert "'does-exist' will be included in the cross-build environment" in captured.out
 
 
+@pytest.mark.serial
 def test_no_test_sources(tmp_path, capfd):
-    """Build will fail if test-sources isn't defined."""
+    """Build will provide a helpful error if pytest is run and test-sources is not defined."""
     if utils.get_platform() != "macos":
         pytest.skip("this test can only run on macOS")
     if utils.get_xcode_version() < (13, 0):
@@ -109,13 +110,47 @@ def test_no_test_sources(tmp_path, capfd):
             add_env={
                 "CIBW_PLATFORM": "ios",
                 "CIBW_BUILD": "cp313-*",
-                "CIBW_TEST_COMMAND": "python -m tests",
+                "CIBW_TEST_REQUIRES": "pytest",
+                "CIBW_TEST_COMMAND": "python -m pytest",
+                "CIBW_XBUILD_TOOLS": "",
             },
         )
 
     # The error message indicates the configuration issue.
     captured = capfd.readouterr()
-    assert "Testing on iOS requires a definition of test-sources." in captured.err
+    assert (
+        "you must copy your test files to the testbed app by setting the `test-sources` option"
+        in captured.out + captured.err
+    )
+
+
+def test_ios_testing_with_placeholder(tmp_path, capfd):
+    """Build will run tests with the {project} placeholder."""
+    if utils.get_platform() != "macos":
+        pytest.skip("this test can only run on macOS")
+    if utils.get_xcode_version() < (13, 0):
+        pytest.skip("this test only works with Xcode 13.0 or greater")
+
+    project_dir = tmp_path / "project"
+    basic_project = test_projects.new_c_project()
+    basic_project.files.update(basic_project_files)
+    basic_project.generate(project_dir)
+
+    with pytest.raises(subprocess.CalledProcessError):
+        utils.cibuildwheel_run(
+            project_dir,
+            add_env={
+                "CIBW_PLATFORM": "ios",
+                "CIBW_BUILD": "cp313-*",
+                "CIBW_TEST_REQUIRES": "pytest",
+                "CIBW_TEST_COMMAND": "pytest {project}/tests",
+                "CIBW_XBUILD_TOOLS": "",
+            },
+        )
+
+    # The error message indicates the configuration issue.
+    captured = capfd.readouterr()
+    assert "iOS tests cannot use placeholders" in captured.out + captured.err
 
 
 def test_missing_xbuild_tool(tmp_path, capfd):

test/test_macos_archs.py

@@ -42,11 +42,9 @@ def test_cross_compiled_build(tmp_path):
 @pytest.mark.parametrize(
     "test_config",
     [
-        # Run the test suite in the project folder
         {
             "CIBW_TEST_COMMAND": '''python -c "import platform; print('running tests on ' + platform.machine())"''',
         },
-        # Nominate the set of test sources to copy
         {
             "CIBW_TEST_COMMAND": "python tests/test_suite.py",
             "CIBW_TEST_SOURCES": "tests",

test/test_pyodide.py

@@ -129,7 +129,7 @@ def test_pyodide_build_and_test(tmp_path, expect_failure):
             add_args=["--platform", "pyodide"],
             add_env={
                 "CIBW_TEST_REQUIRES": "pytest",
-                "CIBW_TEST_COMMAND": "python -m pytest",
+                "CIBW_TEST_COMMAND": "python -m pytest {project}",
             },
         )
         # check that the expected wheels are produced

test/test_testing.py

@@ -86,10 +86,10 @@ def test(tmp_path):
             "CIBW_TEST_REQUIRES": "pytest",
             # the 'false ||' bit is to ensure this command runs in a shell on
             # mac/linux.
-            "CIBW_TEST_COMMAND": f"false || {utils.invoke_pytest()} ./test",
+            "CIBW_TEST_COMMAND": f"false || {utils.invoke_pytest()} {{project}}/test",
             # pytest fails on GraalPy 24.2.0 on Windows so we skip it there
             # until https://github.com/oracle/graalpython/issues/490 is fixed
-            "CIBW_TEST_COMMAND_WINDOWS": "COLOR 00 || where graalpy || pytest ./test",
+            "CIBW_TEST_COMMAND_WINDOWS": "COLOR 00 || where graalpy || pytest {project}/test",
         },
     )
 
@@ -109,10 +109,10 @@ def test_extras_require(tmp_path):
             "CIBW_TEST_EXTRAS": "test",
             # the 'false ||' bit is to ensure this command runs in a shell on
             # mac/linux.
-            "CIBW_TEST_COMMAND": f"false || {utils.invoke_pytest()} ./test",
+            "CIBW_TEST_COMMAND": f"false || {utils.invoke_pytest()} {{project}}/test",
             # pytest fails on GraalPy 24.2.0 on Windows so we skip it there
             # until https://github.com/oracle/graalpython/issues/490 is fixed
-            "CIBW_TEST_COMMAND_WINDOWS": "COLOR 00 || where graalpy || pytest ./test",
+            "CIBW_TEST_COMMAND_WINDOWS": "COLOR 00 || where graalpy || pytest {project}/test",
         },
         single_python=True,
     )
@@ -143,10 +143,10 @@ def test_dependency_groups(tmp_path):
             "CIBW_TEST_GROUPS": "dev",
             # the 'false ||' bit is to ensure this command runs in a shell on
             # mac/linux.
-            "CIBW_TEST_COMMAND": f"false || {utils.invoke_pytest()} ./test",
+            "CIBW_TEST_COMMAND": f"false || {utils.invoke_pytest()} {{project}}/test",
             # pytest fails on GraalPy 24.2.0 on Windows so we skip it there
             # until https://github.com/oracle/graalpython/issues/490 is fixed
-            "CIBW_TEST_COMMAND_WINDOWS": "COLOR 00 || where graalpy || pytest ./test",
+            "CIBW_TEST_COMMAND_WINDOWS": "COLOR 00 || where graalpy || pytest {project}/test",
         },
         single_python=True,
     )
@@ -178,7 +178,7 @@ def test_failing_test(tmp_path):
             output_dir=output_dir,
             add_env={
                 "CIBW_TEST_REQUIRES": "pytest",
-                "CIBW_TEST_COMMAND": f"{utils.invoke_pytest()} ./test",
+                "CIBW_TEST_COMMAND": f"{utils.invoke_pytest()} {{project}}/test",
                 # CPython 3.8 when running on macOS arm64 is unusual. The build
                 # always runs in x86_64, so the arm64 tests are not run. See
                 # #1169 for reasons why. That means the build succeeds, which
@@ -191,29 +191,41 @@ def test_failing_test(tmp_path):
 
 
 @pytest.mark.parametrize("test_runner", ["pytest", "unittest"])
-def test_bare_pytest_invocation(tmp_path: Path, test_runner: str) -> None:
+def test_bare_pytest_invocation(
-    """Check that if a user runs a bare test suite, it runs in the project folder"""
+    tmp_path: Path, capfd: pytest.CaptureFixture[str], test_runner: str
+) -> None:
+    """
+    Check that if a user runs pytest in the the test cwd without setting
+    test-sources, it raises a helpful error
+    """
     project_dir = tmp_path / "project"
     project_with_a_test.generate(project_dir)
+    output_dir = tmp_path / "output"
 
-    actual_wheels = utils.cibuildwheel_run(
+    with pytest.raises(subprocess.CalledProcessError):
-        project_dir,
+        utils.cibuildwheel_run(
-        add_env={
+            project_dir,
-            "CIBW_TEST_REQUIRES": "pytest" if test_runner == "pytest" else "",
+            output_dir=output_dir,
-            "CIBW_TEST_COMMAND": (
+            add_env={
-                # pytest fails on GraalPy 24.2.0 on Windows so we skip it there
+                "CIBW_TEST_REQUIRES": "pytest" if test_runner == "pytest" else "",
-                # until https://github.com/oracle/graalpython/issues/490 fixed
+                "CIBW_TEST_COMMAND": (
-                "graalpy.exe -c 1 || python -m pytest"
+                    "python -m pytest" if test_runner == "pytest" else "python -m unittest"
-                if test_runner == "pytest"
+                ),
-                else "python -m unittest discover test spam_test.py"
+                # Skip CPython 3.8 on macOS arm64, see comment above in
-            ),
+                # 'test_failing_test'
-        },
+                "CIBW_SKIP": "cp38-macosx_arm64",
+            },
+        )
+
+    assert len(list(output_dir.iterdir())) == 0
+
+    captured = capfd.readouterr()
+
+    assert (
+        "Please specify a path to your tests when invoking pytest using the {project} placeholder"
+        in captured.out + captured.err
     )
 
-    # check that we got the right wheels
-    expected_wheels = utils.expected_wheels("spam", "0.1.0")
-    assert set(actual_wheels) == set(expected_wheels)
-
 
 def test_test_sources(tmp_path):
     project_dir = tmp_path / "project"