tests: use pytest-subprocess to support Windows & PyPy

Signed-off-by: Henry Schreiner <henryschreineriii@gmail.com>

Author: henryiii

pyproject.toml

@@ -41,6 +41,7 @@ test = [
   'pytest',
   'pytest-cov',
   'pytest-mock',
+  'pytest-virtualenv',
   'GitPython',
   'auditwheel',
   'Cython',

tests/test_pep518.py

@@ -1,5 +1,3 @@
-import subprocess
-
 import pytest
 
 from .conftest import cd_package
@@ -12,16 +10,12 @@
     ]
 )
 @pytest.mark.parametrize(
-    'build_args', [(), ('--wheel',)], ids=['sdist_to_wheel', 'wheel_directly']
+    'build_args', ['', '--wheel'], ids=['sdist_to_wheel', 'wheel_directly']
 )
-def test_pep518(pep518, virtual_env, package, build_args, tmp_path):
+def test_pep518(pep518, virtualenv, package, build_args, tmp_path):
     dist = tmp_path / 'dist'
 
-    result = subprocess.run([str(virtual_env), '-m', 'pip', 'install', 'build'], check=False)
-    assert result.returncode == 0
+    virtualenv.run('python -m pip install build')
 
-    with cd_package(package):
-        result = subprocess.run(
-            [str(virtual_env), '-m', 'build', f'--outdir={dist}', *build_args], check=False
-        )
-        assert result.returncode == 0
+    with cd_package(package) as package_dir:
+        virtualenv.run(f'python -m build --outdir={dist} {build_args}', cwd=package_dir)