Passenv: Include default env variables regardless of their case on UNIX

This fixes problems with environment variables
that are also used in their lower-case form,
such as http_proxy and https_proxy.
This applies only to UNIX systems since Windows is case-insensitive.

Closes #2372

CONTRIBUTORS

@@ -35,6 +35,7 @@ David Diaz
 Ederag
 Eli Collins
 Eugene Yunak
+Fabian Poggenhans
 Felix Hildén
 Fernando L. Pereira
 Florian Bruhin

docs/changelog/2372.feature.rst

@@ -0,0 +1 @@
+Add default environment variables (such as http_proxy) regardless of their case to passenv on UNIX -- by :user:`poggenhans`.

docs/config.rst

@@ -460,7 +460,8 @@ Complete list of settings that you can put into ``testenv*`` sections:
     ``A`` will pass both ``A`` and ``a``.
 
     Some variables are always passed through to ensure the basic functionality
-    of standard library functions or tooling like pip:
+    of standard library functions or tooling like pip.
+    This is also not case sensitive on all platforms except Windows:
 
     * passed through on all platforms: ``CURL_CA_BUNDLE``, ``PATH``,
       ``LANG``, ``LANGUAGE``,

src/tox/config/__init__.py

@@ -809,6 +809,10 @@ def passenv(testenv_config, value):
             passenv.add("MSYSTEM")  # fixes #429
         else:
             passenv.add("TMPDIR")
+
+            # add non-uppercased variables to passenv if present (only necessary for UNIX)
+            passenv.update(name for name in os.environ if name.upper() in passenv)
+
         for spec in value:
             for name in os.environ:
                 if fnmatchcase(name.upper(), spec.upper()):

tests/unit/config/test_config.py

@@ -1494,6 +1494,8 @@ def test_passenv_as_multiline_list(self, newconfig, monkeypatch, plat):
         monkeypatch.setenv("A123A", "a")
         monkeypatch.setenv("A123B", "b")
         monkeypatch.setenv("BX23", "0")
+        if plat == "linux2":
+            monkeypatch.setenv("http_proxy", "c")
         config = newconfig(
             """
             [testenv]
@@ -1518,6 +1520,7 @@ def test_passenv_as_multiline_list(self, newconfig, monkeypatch, plat):
             assert "MSYSTEM" in envconfig.passenv
         else:
             assert "TMPDIR" in envconfig.passenv
+            assert "http_proxy" in envconfig.passenv
         assert "CURL_CA_BUNDLE" in envconfig.passenv
         assert "PATH" in envconfig.passenv
         assert "PIP_INDEX_URL" in envconfig.passenv