Make test_pip_upgrade_from_source xdist-friendly

setuptools/tests/test_virtualenv.py

@@ -1,6 +1,8 @@
 import glob
 import os
+import shutil
 import sys
+import subprocess
 
 import pathlib
 
@@ -85,32 +87,46 @@ def _get_pip_versions():
 
 
 @pytest.mark.parametrize('pip_version', _get_pip_versions())
-def test_pip_upgrade_from_source(pip_version, virtualenv):
+def test_pip_upgrade_from_source(pip_version, tmp_path, virtualenv):
     """
     Check pip can upgrade setuptools from source.
     """
+    dist_dir = virtualenv.workspace
+    venv_python = virtualenv.python
+    venv_pip = f'{venv_python} -m pip'
+
+    # NOTE: The source dir is copied so that multiple parallel runs
+    # NOTE: of `setup.py sdist/bdist_wheel` don't remove each other's
+    # NOTE: egg directories.
+    tmp_src = tmp_path / 'src'
+    shutil.copytree(SOURCE_DIR, tmp_src)
+
     # Install pip/wheel, and remove setuptools (as it
     # should not be needed for bootstraping from source)
-    if pip_version is None:
-        upgrade_pip = ()
-    else:
-        upgrade_pip = ('python -m pip install -U {pip_version} --retries=1',)
-    virtualenv.run(' && '.join((
-        'pip uninstall -y setuptools',
-        'pip install -U wheel',
-    ) + upgrade_pip).format(pip_version=pip_version))
-    dist_dir = virtualenv.workspace
+    upgrade_pip = () if pip_version is None else (
+        f'{venv_pip} install -U {pip_version} --retries=1',
+    )
+    subprocess.check_call(' && '.join((
+        f'{venv_pip} uninstall -y setuptools',
+        f'{venv_pip} install -U wheel',
+        *upgrade_pip,
+    )), shell=True)
+
     # Generate source distribution / wheel.
-    virtualenv.run(' && '.join((
-        'python setup.py -q sdist -d {dist}',
-        'python setup.py -q bdist_wheel -d {dist}',
-    )).format(dist=dist_dir), cd=SOURCE_DIR)
+    subprocess.check_call(' && '.join((
+        f'{venv_python} setup.py -q sdist -d {dist_dir}',
+        f'{venv_python} setup.py -q bdist_wheel -d {dist_dir}',
+    )), shell=True, cwd=tmp_src)
     sdist = glob.glob(os.path.join(dist_dir, '*.zip'))[0]
     wheel = glob.glob(os.path.join(dist_dir, '*.whl'))[0]
+
     # Then update from wheel.
-    virtualenv.run('pip install ' + wheel)
+    subprocess.check_call(f'{venv_pip} install {wheel}', shell=True)
     # And finally try to upgrade from source.
-    virtualenv.run('pip install --no-cache-dir --upgrade ' + sdist)
+    subprocess.check_call(
+        f'{venv_pip} install --no-cache-dir --upgrade {sdist}',
+        shell=True,
+    )
 
 
 def _check_test_command_install_requirements(virtualenv, tmpdir):