diff --git a/managed_vms/mailgun/main_test.py b/managed_vms/mailgun/main_test.py
new file mode 100644
index 000000000000..0a4dff8a6b9c
--- /dev/null
+++ b/managed_vms/mailgun/main_test.py
@@ -0,0 +1,78 @@
+# Copyright 2015 Google Inc. All rights reserved.
+#
+# 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 os
+import re
+
+import pytest
+import responses
+
+
+@pytest.fixture
+def app(monkeypatch):
+    monkeypatch.setenv('MAILGUN_DOMAIN_NAME', 'example.com')
+    monkeypatch.setenv('MAILGUN_API_KEY', 'apikey')
+
+    import main
+
+    main.app.testing = True
+    return main.app.test_client()
+
+
+def test_index(app):
+    r = app.get('/')
+    assert r.status_code == 200
+
+
+@responses.activate
+def test_send_error(app):
+    responses.add(
+        responses.POST,
+        re.compile(r'.*'),
+        body='Test error',
+        status=500)
+
+    with pytest.raises(Exception):
+        app.post('/send/email', data={
+            'recipient': 'user@example.com',
+            'submit': 'Send simple email'})
+
+
+@responses.activate
+def test_send_simple(app):
+    responses.add(
+        responses.POST,
+        re.compile(r'.*'),
+        body='')
+
+    response = app.post('/send/email', data={
+        'recipient': 'user@example.com',
+        'submit': 'Send simple email'})
+    assert response.status_code == 200
+
+
+@responses.activate
+def test_send_complex(app, monkeypatch):
+    import main
+    monkeypatch.chdir(os.path.dirname(main.__file__))
+
+    responses.add(
+        responses.POST,
+        re.compile(r'.*'),
+        body='')
+
+    response = app.post('/send/email', data={
+        'recipient': 'user@example.com',
+        'submit': 'Send complex email'})
+    assert response.status_code == 200