Patch the PYTHONPATH when invoking subprocess commands that rely on setuptools...

Patch the PYTHONPATH when invoking subprocess commands that rely on setuptools under test. Fixes #884.

setuptools/tests/namespaces.py

 from __future__ import absolute_import, unicode_literals
 
+import os
 import textwrap
 
 
@@ -40,3 +41,15 @@ def make_site_dir(target):
     target_str = str(target)
     tmpl = '__import__("site").addsitedir({target_str!r})'
     sc.write_text(tmpl.format(**locals()), encoding='utf-8')
+
+
+def build_pythonpath(*paths):
+    """
+    Create a PYTHONPATH value for the indicated paths, casting
+    them to strings, but also injecting the CWD ahead of the
+    values to ensure that this setuptools is used if the tests
+    are invoked without this setuptools being installed.
+    See #884.
+    """
+    paths = (os.getcwd(),) + paths
+    return os.pathsep.join(map(str, paths))

setuptools/tests/test_develop.py

@@ -132,7 +132,7 @@ class TestNamespaces:
             'develop',
             '--install-dir', str(target),
         ]
-        env = dict(PYTHONPATH=str(target))
+        env = dict(PYTHONPATH=namespaces.build_pythonpath(target))
         with src_dir.as_cwd():
             subprocess.check_call(develop_cmd, env=env)
 
@@ -162,7 +162,7 @@ class TestNamespaces:
             sys.executable,
             '-c', 'import myns.pkgA; import myns.pkgB',
         ]
-        env = dict(PYTHONPATH=str(target))
+        env = dict(PYTHONPATH=namespaces.build_pythonpath(target))
         subprocess.check_call(try_import, env=env)
 
         # additionally ensure that pkg_resources import works

setuptools/tests/test_namespaces.py

@@ -26,8 +26,7 @@ class TestNamespaces:
         pkg_B = namespaces.build_namespace_package(tmpdir, 'myns.pkgB')
         site_packages = tmpdir / 'site-packages'
         path_packages = tmpdir / 'path-packages'
-        targets = site_packages, path_packages
-        python_path = os.pathsep.join(map(str, targets))
+        python_path = namespaces.build_pythonpath(site_packages, path_packages)
         # use pip to install to the target directory
         install_cmd = [
             'pip',
@@ -61,7 +60,7 @@ class TestNamespaces:
         pkg = namespaces.build_namespace_package(tmpdir, 'myns.pkgA')
         target = tmpdir / 'packages'
         target.mkdir()
-        env = dict(PYTHONPATH=str(target))
+        env = dict(PYTHONPATH=namespaces.build_pythonpath(target))
         install_cmd = [
             sys.executable,
             '-m', 'easy_install',
@@ -100,5 +99,5 @@ class TestNamespaces:
             sys.executable,
             '-c', 'import pkg_resources; import myns.pkgA',
         ]
-        env = dict(PYTHONPATH=str(target))
+        env = dict(PYTHONPATH=namespaces.build_pythonpath(target))
         subprocess.check_call(pkg_resources_imp, env=env, cwd=str(pkg_A))