diff --git a/tests/integration/credentials/utils_test.py b/tests/integration/credentials/utils_test.py
index acf018d2..46440397 100644
--- a/tests/integration/credentials/utils_test.py
+++ b/tests/integration/credentials/utils_test.py
@@ -7,7 +7,7 @@ from unittest import mock
 @mock.patch.dict(os.environ)
 def test_create_environment_dict():
     base = {'FOO': 'bar', 'BAZ': 'foobar'}
-    os.environ = base
+    os.environ = base  # noqa: B003
     assert create_environment_dict({'FOO': 'baz'}) == {
         'FOO': 'baz', 'BAZ': 'foobar',
     }
diff --git a/tests/unit/client_test.py b/tests/unit/client_test.py
index 1148d7ac..7012b212 100644
--- a/tests/unit/client_test.py
+++ b/tests/unit/client_test.py
@@ -153,7 +153,8 @@ class FromEnvTest(unittest.TestCase):
         self.os_environ = os.environ.copy()
 
     def tearDown(self):
-        os.environ = self.os_environ
+        os.environ.clear()
+        os.environ.update(self.os_environ)
 
     def test_from_env(self):
         """Test that environment variables are passed through to
diff --git a/tests/unit/utils_test.py b/tests/unit/utils_test.py
index 9c8a55bd..b47cb0c6 100644
--- a/tests/unit/utils_test.py
+++ b/tests/unit/utils_test.py
@@ -59,7 +59,8 @@ class KwargsFromEnvTest(unittest.TestCase):
         self.os_environ = os.environ.copy()
 
     def tearDown(self):
-        os.environ = self.os_environ
+        os.environ.clear()
+        os.environ.update(self.os_environ)
 
     def test_kwargs_from_env_empty(self):
         os.environ.update(DOCKER_HOST='',