diff --git a/tests/conftest.py b/tests/conftest.py
new file mode 100644
index 0000000..c9e3f84
--- /dev/null
+++ b/tests/conftest.py
@@ -0,0 +1,37 @@
+# Copyright 2016 Google Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import sys
+
+import mock
+import pytest
+
+
+@pytest.fixture
+def mock_non_existent_module(monkeypatch):
+    """Mocks a non-existing module in sys.modules.
+
+    Additionally mocks any non-existing modules specified in the dotted path.
+    """
+    def _mock_non_existent_module(path):
+        parts = path.split('.')
+        partial = []
+        for part in parts:
+            partial.append(part)
+            current_module = '.'.join(partial)
+            if current_module not in sys.modules:
+                monkeypatch.setitem(
+                    sys.modules, current_module, mock.MagicMock())
+
+    return _mock_non_existent_module