diff --git a/.gitignore b/.gitignore
index 49dd343e..8e51e96d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -20,4 +20,5 @@ docs/build
 .pytest_cache
 
 #PyCharm
-.idea/
\ No newline at end of file
+.idea/
+venv/
diff --git a/test/integration/integration_test_utils.py b/test/integration/integration_test_utils.py
index c037cf3d..1bb15d58 100644
--- a/test/integration/integration_test_utils.py
+++ b/test/integration/integration_test_utils.py
@@ -28,8 +28,7 @@
 DDB_TABLE_NAME = "DDB_ENCRYPTION_CLIENT_TEST_TABLE_NAME"
 
 
-@pytest.fixture
-def cmk_arn():
+def cmk_arn_value():
     """Retrieve the target CMK ARN from environment variable."""
     arn = os.environ.get(AWS_KMS_KEY_ID, None)
     if arn is None:
@@ -43,9 +42,15 @@ def cmk_arn():
     raise ValueError("KMS CMK ARN provided for integration tests must be a key not an alias")
 
 
+@pytest.fixture
+def cmk_arn():
+    """As of Pytest 4.0.0, fixtures cannot be called directly."""
+    return cmk_arn_value()
+
+
 @pytest.fixture
 def aws_kms_cmp():
-    return AwsKmsCryptographicMaterialsProvider(key_id=cmk_arn())
+    return AwsKmsCryptographicMaterialsProvider(key_id=cmk_arn_value())
 
 
 @pytest.fixture