Check if using xdist may help with performance problems

.github/workflows/test.yml

@@ -22,6 +22,7 @@ jobs:
     name: Test cibuildwheel on ${{ matrix.os }}
     runs-on: ${{ matrix.os }}
     strategy:
+      fail-fast: false
       matrix:
         os: [ubuntu-18.04, windows-latest, macos-latest]
         python_version: ['3.7']

bin/run_tests.py

@@ -17,4 +17,4 @@
     subprocess.check_call(unit_test_args)
 
     # run the integration tests
-    subprocess.check_call([sys.executable, '-m', 'pytest', '-x', '--durations', '0', 'test'])
+    subprocess.check_call([sys.executable, '-m', 'pytest', '-x', '--durations', '0', 'test', '-n', '2', '--dist=loadfile'])

cibuildwheel/windows.py

@@ -17,6 +17,8 @@
 IS_RUNNING_ON_AZURE = Path('C:\\hostedtoolcache').exists()
 IS_RUNNING_ON_TRAVIS = os.environ.get('TRAVIS_OS_NAME') == 'windows'
 
+INSTALL_PATH = 'C:\\cibw'
+
 
 def call(args: Sequence[Union[str, PathLike]], env: Optional[Dict[str, str]] = None,
          cwd: Optional[str] = None) -> None:
@@ -35,7 +37,7 @@ def get_nuget_args(version: str, arch: str) -> List[str]:
     python_name = 'python' if version[0] == '3' else 'python2'
     if arch == '32':
         python_name = python_name + 'x86'
-    return [python_name, '-Version', version, '-OutputDirectory', 'C:\\cibw\\python']
+    return [python_name, '-Version', version, '-OutputDirectory', INSTALL_PATH + '\\python']
 
 
 class PythonConfiguration(NamedTuple):
@@ -84,7 +86,8 @@ def extract_zip(zip_src: Path, dest: Path) -> None:
 def install_cpython(version: str, arch: str, nuget: Path) -> Path:
     nuget_args = get_nuget_args(version, arch)
     installation_path = Path(nuget_args[-1]) / (nuget_args[0] + '.' + version) / 'tools'
-    call([nuget, 'install', *nuget_args])
+    if not installation_path.exists():
+        call([nuget, 'install', *nuget_args])
     return installation_path
 
 
@@ -94,9 +97,9 @@ def install_pypy(version: str, arch: str, url: str) -> Path:
     zip_filename = url.rsplit('/', 1)[-1]
     extension = ".zip"
     assert zip_filename.endswith(extension)
-    installation_path = Path('C:\\cibw') / zip_filename[:-len(extension)]
+    installation_path = Path(INSTALL_PATH) / zip_filename[:-len(extension)]
     if not installation_path.exists():
-        pypy_zip = Path('C:\\cibw') / zip_filename
+        pypy_zip = Path(INSTALL_PATH) / zip_filename
         download(url, pypy_zip)
         # Extract to the parent directory because the zip file still contains a directory
         extract_zip(pypy_zip, installation_path.parent)
@@ -106,7 +109,7 @@ def install_pypy(version: str, arch: str, url: str) -> Path:
 
 
 def setup_python(python_configuration: PythonConfiguration, dependency_constraint_flags: Sequence[Union[str, PathLike]], environment: ParsedEnvironment) -> Dict[str, str]:
-    nuget = Path('C:\\cibw\\nuget.exe')
+    nuget = Path(INSTALL_PATH + '\\nuget.exe')
     if not nuget.exists():
         download('https://dist.nuget.org/win-x86-commandline/latest/nuget.exe', nuget)
 
@@ -143,7 +146,7 @@ def setup_python(python_configuration: PythonConfiguration, dependency_constrain
 
     # make sure pip is installed
     if not (installation_path / 'Scripts' / 'pip.exe').exists():
-        call(['python', get_pip_script, *dependency_constraint_flags], env=env, cwd="C:\\cibw")
+        call(['python', get_pip_script, *dependency_constraint_flags], env=env, cwd=INSTALL_PATH)
     assert (installation_path / 'Scripts' / 'pip.exe').exists()
     where_pip = subprocess.check_output(['where', 'pip'], env=env, universal_newlines=True).splitlines()[0].strip()
     if where_pip.strip() != str(installation_path / 'Scripts' / 'pip.exe'):
@@ -195,7 +198,7 @@ def build(options: BuildOptions) -> None:
     repaired_wheel_dir = temp_dir / 'repaired_wheel'
 
     # install nuget as best way to provide python
-    nuget = Path('C:\\cibw\\nuget.exe')
+    nuget = Path(INSTALL_PATH + '\\nuget.exe')
     download('https://dist.nuget.org/win-x86-commandline/latest/nuget.exe', nuget)
 
     if options.before_all:

requirements-dev.txt

@@ -1,6 +1,7 @@
 -e .
 -e ./docs/mkdocs_include_markdown_plugin
 pytest
+pytest-xdist
 mkdocs==1.0.4
 pymdown-extensions
 pip-tools

test/conftest.py

@@ -0,0 +1,13 @@
+import pytest
+
+import cibuildwheel.windows
+
+
+@pytest.fixture(autouse=True)
+def setup_python(monkeypatch, request):
+    try:
+        from xdist.plugin import get_xdist_worker_id
+        worker_id = get_xdist_worker_id(request)
+        monkeypatch.setattr(cibuildwheel.windows, "INSTALL_PATH", 'C:\\cibw\\{}'.format(worker_id))
+    except ImportError:
+        pass