Change to the iOS testing option semantics

Don't assume the presence of `python -m` in the test command. Less magic
and allows more option reuse between platforms.

Author: joerick

cibuildwheel/platforms/ios.py

@@ -32,7 +32,7 @@
     download,
     move_file,
 )
-from ..util.helpers import prepare_command
+from ..util.helpers import prepare_command, unwrap
 from ..util.packaging import (
     combine_constraints,
     find_compatible_wheel,
@@ -593,14 +593,34 @@ def build(options: Options, tmp_path: Path) -> None:
                     )
 
                     log.step("Running test suite...")
+
+                    test_command_parts = shlex.split(build_options.test_command)
+                    if test_command_parts[0:2] != ["python", "-m"]:
+                        log.warning(
+                            unwrap(f"""
+                                iOS tests run with test command '{build_options.test_command}' that
+                                doesn't start with 'python -m'. iOS tests must execute python
+                                modules - other entrypoints are not supported.
+
+                                cibuildwheel will try to execute it as if it started with 'python
+                                -m'. If this works, all you need to do is add that to your test
+                                command.
+                            """)
+                        )
+                    else:
+                        # the testbed run command actually doesn't want the
+                        # python -m prefix - it's implicit, so we remove it
+                        # here.
+                        test_command_parts = test_command_parts[2:]
+
                     try:
                         call(
                             "python",
                             testbed_path,
                             "run",
                             *(["--verbose"] if build_options.build_verbosity > 0 else []),
                             "--",
-                            *(shlex.split(build_options.test_command)),
+                            *test_command_parts,
                             env=build_env,
                         )
                         failed = False

docs/options.md

@@ -1242,7 +1242,7 @@ run your test suite.
 
 On all platforms other than iOS, the command is run in a shell, so you can write things like `cmd1 && cmd2`.
 
-On iOS, the value of the `CIBW_TEST_COMMAND` setting is interpreted as the arguments to pass to `python -m` - that is, a Python module name, followed by arguments that will be assigned to `sys.argv`. Shell commands cannot be used.
+On iOS, the value of the `CIBW_TEST_COMMAND` setting should follow the format `python -m MODULE [...ARGS]` - where MODULE is a Python module name, followed by arguments that will be assigned to `sys.argv`. Shell commands cannot be used.
 
 Platform-specific environment variables are also available:<br/>
 `CIBW_TEST_COMMAND_MACOS` | `CIBW_TEST_COMMAND_WINDOWS` | `CIBW_TEST_COMMAND_LINUX` | `CIBW_TEST_COMMAND_IOS` | `CIBW_TEST_COMMAND_PYODIDE`
@@ -1262,6 +1262,10 @@ Platform-specific environment variables are also available:<br/>
     CIBW_TEST_COMMAND: >
       pytest ./tests &&
       python ./test.py
+
+    # run tests on ios
+    CIBW_TEST_SOURCES_IOS: tests
+    CIBW_TEST_COMMAND_IOS: python -m pytest ./tests
     ```
 
 !!! tab examples "pyproject.toml"
@@ -1279,6 +1283,11 @@ Platform-specific environment variables are also available:<br/>
       "pytest ./tests",
       "python ./test.py",
     ]
+
+    # run tests on ios
+    [tool.cibuildwheel.ios]
+    test-sources = ["tests"]
+    test-command = "python -m pytest ./tests"
     ```
 
     In configuration files, you can use an array, and the items will be joined with `&&`.

test/test_ios.py

@@ -73,7 +73,7 @@ def test_ios_platforms(tmp_path, build_config, monkeypatch, capfd):
             "CIBW_BUILD": "cp313-*",
             "CIBW_XBUILD_TOOLS": "does-exist",
             "CIBW_TEST_SOURCES": "tests",
-            "CIBW_TEST_COMMAND": "unittest discover tests test_platform.py",
+            "CIBW_TEST_COMMAND": "python -m unittest discover tests test_platform.py",
             "CIBW_BUILD_VERBOSITY": "1",
             **build_config,
         },
@@ -119,7 +119,7 @@ def test_no_test_sources(tmp_path, capfd):
             add_env={
                 "CIBW_PLATFORM": "ios",
                 "CIBW_BUILD": "cp313-*",
-                "CIBW_TEST_COMMAND": "tests",
+                "CIBW_TEST_COMMAND": "python -m tests",
             },
         )
 
@@ -146,7 +146,7 @@ def test_missing_xbuild_tool(tmp_path, capfd):
             add_env={
                 "CIBW_PLATFORM": "ios",
                 "CIBW_BUILD": "cp313-*",
-                "CIBW_TEST_COMMAND": "tests",
+                "CIBW_TEST_COMMAND": "python -m tests",
                 "CIBW_XBUILD_TOOLS": "does-not-exist",
             },
         )