gh-131277: allow EnvironmentVarGuard to unset more than one environment variable at once (#131280)

Co-authored-by: Hugo van Kemenade <[email protected]>

Author: picnixz

Doc/library/test.rst

@@ -1435,9 +1435,12 @@ The :mod:`test.support.os_helper` module provides support for os tests.
    ``value``.
 
 
-.. method:: EnvironmentVarGuard.unset(envvar)
+.. method:: EnvironmentVarGuard.unset(envvar, *others)
 
-   Temporarily unset the environment variable ``envvar``.
+   Temporarily unset one or more environment variables.
+
+   .. versionchanged:: next
+      More than one environment variable can be unset.
 
 
 .. function:: can_symlink()

Lib/test/support/__init__.py

@@ -2855,8 +2855,7 @@ def no_color():
         swap_attr(_colorize, "can_colorize", lambda file=None: False),
         EnvironmentVarGuard() as env,
     ):
-        for var in {"FORCE_COLOR", "NO_COLOR", "PYTHON_COLORS"}:
-            env.unset(var)
+        env.unset("FORCE_COLOR", "NO_COLOR", "PYTHON_COLORS")
         env.set("NO_COLOR", "1")
         yield
 

Lib/test/support/os_helper.py

@@ -720,9 +720,10 @@ def temp_umask(umask):
 
 
 class EnvironmentVarGuard(collections.abc.MutableMapping):
+    """Class to help protect the environment variable properly.
 
-    """Class to help protect the environment variable properly.  Can be used as
-    a context manager."""
+    Can be used as a context manager.
+    """
 
     def __init__(self):
         self._environ = os.environ
@@ -756,8 +757,10 @@ def __len__(self):
     def set(self, envvar, value):
         self[envvar] = value
 
-    def unset(self, envvar):
-        del self[envvar]
+    def unset(self, envvar, /, *envvars):
+        """Unset one or more environment variables."""
+        for ev in (envvar, *envvars):
+            del self[ev]
 
     def copy(self):
         # We do what os.environ.copy() does.

Lib/test/test__colorize.py

@@ -10,8 +10,7 @@
 @contextlib.contextmanager
 def clear_env():
     with EnvironmentVarGuard() as mock_env:
-        for var in "FORCE_COLOR", "NO_COLOR", "PYTHON_COLORS", "TERM":
-            mock_env.unset(var)
+        mock_env.unset("FORCE_COLOR", "NO_COLOR", "PYTHON_COLORS", "TERM")
         yield mock_env
 
 

Lib/test/test__osx_support.py

@@ -20,12 +20,13 @@ def setUp(self):
         self.prog_name = 'bogus_program_xxxx'
         self.temp_path_dir = os.path.abspath(os.getcwd())
         self.env = self.enterContext(os_helper.EnvironmentVarGuard())
-        for cv in ('CFLAGS', 'LDFLAGS', 'CPPFLAGS',
-                            'BASECFLAGS', 'BLDSHARED', 'LDSHARED', 'CC',
-                            'CXX', 'PY_CFLAGS', 'PY_LDFLAGS', 'PY_CPPFLAGS',
-                            'PY_CORE_CFLAGS', 'PY_CORE_LDFLAGS'):
-            if cv in self.env:
-                self.env.unset(cv)
+
+        self.env.unset(
+            'CFLAGS', 'LDFLAGS', 'CPPFLAGS',
+            'BASECFLAGS', 'BLDSHARED', 'LDSHARED', 'CC',
+            'CXX', 'PY_CFLAGS', 'PY_LDFLAGS', 'PY_CPPFLAGS',
+            'PY_CORE_CFLAGS', 'PY_CORE_LDFLAGS'
+        )
 
     def add_expected_saved_initial_values(self, config_vars, expected_vars):
         # Ensure that the initial values for all modified config vars

Lib/test/test_builtin.py

@@ -1568,8 +1568,7 @@ def test_open_default_encoding(self):
             # try to get a user preferred encoding different than the current
             # locale encoding to check that open() uses the current locale
             # encoding and not the user preferred encoding
-            for key in ('LC_ALL', 'LANG', 'LC_CTYPE'):
-                env.unset(key)
+            env.unset('LC_ALL', 'LANG', 'LC_CTYPE')
 
             self.write_testfile()
             current_locale_encoding = locale.getencoding()

Lib/test/test_getopt.py

@@ -13,8 +13,7 @@
 class GetoptTests(unittest.TestCase):
     def setUp(self):
         self.env = self.enterContext(EnvironmentVarGuard())
-        if "POSIXLY_CORRECT" in self.env:
-            del self.env["POSIXLY_CORRECT"]
+        del self.env["POSIXLY_CORRECT"]
 
     def assertError(self, *args, **kwargs):
         self.assertRaises(getopt.GetoptError, *args, **kwargs)

Lib/test/test_io.py

@@ -2896,8 +2896,7 @@ def test_default_encoding(self):
             # try to get a user preferred encoding different than the current
             # locale encoding to check that TextIOWrapper() uses the current
             # locale encoding and not the user preferred encoding
-            for key in ('LC_ALL', 'LANG', 'LC_CTYPE'):
-                env.unset(key)
+            env.unset('LC_ALL', 'LANG', 'LC_CTYPE')
 
             current_locale_encoding = locale.getencoding()
             b = self.BytesIO()

Lib/test/test_locale.py

@@ -500,9 +500,7 @@ def test_defaults_UTF8(self):
 
         try:
             with os_helper.EnvironmentVarGuard() as env:
-                for key in ('LC_ALL', 'LC_CTYPE', 'LANG', 'LANGUAGE'):
-                    env.unset(key)
-
+                env.unset('LC_ALL', 'LC_CTYPE', 'LANG', 'LANGUAGE')
                 env.set('LC_CTYPE', 'UTF-8')
 
                 with check_warnings(('', DeprecationWarning)):

Lib/test/test_pathlib/test_pathlib.py

@@ -3232,7 +3232,7 @@ def test_expanduser_posix(self):
         p7 = P(f'~{fakename}/Documents')
 
         with os_helper.EnvironmentVarGuard() as env:
-            env.pop('HOME', None)
+            env.unset('HOME')
 
             self.assertEqual(p1.expanduser(), P(userhome) / 'Documents')
             self.assertEqual(p2.expanduser(), P(userhome) / 'Documents')
@@ -3345,10 +3345,7 @@ def test_absolute_windows(self):
     def test_expanduser_windows(self):
         P = self.cls
         with os_helper.EnvironmentVarGuard() as env:
-            env.pop('HOME', None)
-            env.pop('USERPROFILE', None)
-            env.pop('HOMEPATH', None)
-            env.pop('HOMEDRIVE', None)
+            env.unset('HOME', 'USERPROFILE', 'HOMEPATH', 'HOMEDRIVE')
             env['USERNAME'] = 'alice'
 
             # test that the path returns unchanged
@@ -3386,8 +3383,7 @@ def check():
             env['HOMEPATH'] = 'Users\\alice'
             check()
 
-            env.pop('HOMEDRIVE', None)
-            env.pop('HOMEPATH', None)
+            env.unset('HOMEDRIVE', 'HOMEPATH')
             env['USERPROFILE'] = 'C:\\Users\\alice'
             check()