Avoid reliance on shell details in test_virtualenv.

setuptools/tests/test_virtualenv.py

@@ -112,10 +112,9 @@ def test_pip_upgrade_from_source(pip_version, virtualenv):
     dist_dir = virtualenv.workspace
     # Generate source distribution / wheel.
     virtualenv.run(' && '.join((
-        'cd {source}',
         'python setup.py -q sdist -d {dist}',
         'python setup.py -q bdist_wheel -d {dist}',
-    )).format(source=SOURCE_DIR, dist=dist_dir))
+    )).format(dist=dist_dir), cd=SOURCE_DIR)
     sdist = glob.glob(os.path.join(dist_dir, '*.zip'))[0]
     wheel = glob.glob(os.path.join(dist_dir, '*.whl'))[0]
     # Then update from wheel.
@@ -180,10 +179,8 @@ def _check_test_command_install_requirements(virtualenv, tmpdir):
             open('success', 'w').close()
             '''))
     # Run test command for test package.
-    virtualenv.run(' && '.join((
-        'cd {tmpdir}',
-        'python setup.py test -s test',
-    )).format(tmpdir=tmpdir))
+    virtualenv.run(
+        ['python', 'setup.py', 'test', '-s', 'test'], cd=str(tmpdir))
     assert tmpdir.join('success').check()
 
 
@@ -204,7 +201,5 @@ def test_no_missing_dependencies(bare_virtualenv):
     Quick and dirty test to ensure all external dependencies are vendored.
     """
     for command in ('upload',):  # sorted(distutils.command.__all__):
-        bare_virtualenv.run(' && '.join((
-            'cd {source}',
-            'python setup.py {command} -h',
-        )).format(command=command, source=SOURCE_DIR))
+        bare_virtualenv.run(
+            ['python', 'setup.py', command, '-h'], cd=SOURCE_DIR)