6 files changed, 31 insertions, 1 deletions
diff --git a/Lib/distutils/tests/test_build_clib.py b/Lib/distutils/tests/test_build_clib.py
index abd8313770e..19e012a58ce 100644
--- a/Lib/distutils/tests/test_build_clib.py
+++ b/Lib/distutils/tests/test_build_clib.py
@@ -2,6 +2,7 @@
 import unittest
 import os
 import sys
+import sysconfig
 
 from test.support import run_unittest, missing_compiler_executable
 
@@ -13,6 +14,15 @@ class BuildCLibTestCase(support.TempdirManager,
                         support.LoggingSilencer,
                         unittest.TestCase):
 
+    def setUp(self):
+        super().setUp()
+        self._backup_CONFIG_VARS = dict(sysconfig._CONFIG_VARS)
+
+    def tearDown(self):
+        super().tearDown()
+        sysconfig._CONFIG_VARS.clear()
+        sysconfig._CONFIG_VARS.update(self._backup_CONFIG_VARS)
+
     def test_check_library_dist(self):
         pkg_dir, dist = self.create_dist()
         cmd = build_clib(dist)
diff --git a/Lib/distutils/tests/test_build_ext.py b/Lib/distutils/tests/test_build_ext.py
index 90f7bb06691..8e7364d2a2c 100644
--- a/Lib/distutils/tests/test_build_ext.py
+++ b/Lib/distutils/tests/test_build_ext.py
@@ -35,6 +35,7 @@ class BuildExtTestCase(TempdirManager,
         site.USER_BASE = self.mkdtemp()
         from distutils.command import build_ext
         build_ext.USER_BASE = site.USER_BASE
+        self.old_config_vars = dict(sysconfig._config_vars)
 
         # bpo-30132: On Windows, a .pdb file may be created in the current
         # working directory. Create a temporary working directory to cleanup
@@ -48,6 +49,8 @@ class BuildExtTestCase(TempdirManager,
         site.USER_BASE = self.old_user_base
         from distutils.command import build_ext
         build_ext.USER_BASE = self.old_user_base
+        sysconfig._config_vars.clear()
+        sysconfig._config_vars.update(self.old_config_vars)
         super(BuildExtTestCase, self).tearDown()
 
     def build_ext(self, *args, **kwargs):
diff --git a/Lib/distutils/tests/test_config_cmd.py b/Lib/distutils/tests/test_config_cmd.py
index 9aeab07b468..0127ba71fc4 100644
--- a/Lib/distutils/tests/test_config_cmd.py
+++ b/Lib/distutils/tests/test_config_cmd.py
@@ -2,6 +2,7 @@
 import unittest
 import os
 import sys
+import sysconfig
 from test.support import run_unittest, missing_compiler_executable
 
 from distutils.command.config import dump_file, config
@@ -21,9 +22,12 @@ class ConfigTestCase(support.LoggingSilencer,
         self._logs = []
         self.old_log = log.info
         log.info = self._info
+        self.old_config_vars = dict(sysconfig._CONFIG_VARS)
 
     def tearDown(self):
         log.info = self.old_log
+        sysconfig._CONFIG_VARS.clear()
+        sysconfig._CONFIG_VARS.update(self.old_config_vars)
         super(ConfigTestCase, self).tearDown()
 
     def test_dump_file(self):
diff --git a/Lib/distutils/tests/test_install.py b/Lib/distutils/tests/test_install.py
index 21a7b7c85c4..0632024b358 100644
--- a/Lib/distutils/tests/test_install.py
+++ b/Lib/distutils/tests/test_install.py
@@ -29,6 +29,15 @@ class InstallTestCase(support.TempdirManager,
                       support.LoggingSilencer,
                       unittest.TestCase):
 
+    def setUp(self):
+        super().setUp()
+        self._backup_config_vars = dict(sysconfig._config_vars)
+
+    def tearDown(self):
+        super().tearDown()
+        sysconfig._config_vars.clear()
+        sysconfig._config_vars.update(self._backup_config_vars)
+
     def test_home_installation_scheme(self):
         # This ensure two things:
         # - that --home generates the desired set of directory names
diff --git a/Lib/distutils/tests/test_unixccompiler.py b/Lib/distutils/tests/test_unixccompiler.py
index eefe4ba4029..24725ead119 100644
--- a/Lib/distutils/tests/test_unixccompiler.py
+++ b/Lib/distutils/tests/test_unixccompiler.py
@@ -12,6 +12,7 @@ class UnixCCompilerTestCase(unittest.TestCase):
     def setUp(self):
         self._backup_platform = sys.platform
         self._backup_get_config_var = sysconfig.get_config_var
+        self._backup_config_vars = dict(sysconfig._config_vars)
         class CompilerWrapper(UnixCCompiler):
             def rpath_foo(self):
                 return self.runtime_library_dir_option('/foo')
@@ -20,6 +21,8 @@ class UnixCCompilerTestCase(unittest.TestCase):
     def tearDown(self):
         sys.platform = self._backup_platform
         sysconfig.get_config_var = self._backup_get_config_var
+        sysconfig._config_vars.clear()
+        sysconfig._config_vars.update(self._backup_config_vars)
 
     @unittest.skipIf(sys.platform == 'win32', "can't test on Windows")
     def test_runtime_libdir_option(self):
diff --git a/Lib/distutils/tests/test_util.py b/Lib/distutils/tests/test_util.py
index bf0d4333f9a..d4a01c6e91c 100644
--- a/Lib/distutils/tests/test_util.py
+++ b/Lib/distutils/tests/test_util.py
@@ -54,7 +54,8 @@ class UtilTestCase(support.EnvironGuard, unittest.TestCase):
             os.uname = self.uname
         else:
             del os.uname
-        sysconfig._config_vars = copy(self._config_vars)
+        sysconfig._config_vars.clear()
+        sysconfig._config_vars.update(self._config_vars)
         super(UtilTestCase, self).tearDown()
 
     def _set_uname(self, uname):