diff --git a/django_mailbox/tests/base.py b/django_mailbox/tests/base.py
index 621152f..5e50fa4 100644
--- a/django_mailbox/tests/base.py
+++ b/django_mailbox/tests/base.py
@@ -40,9 +40,9 @@ class EmailMessageTestCase(TestCase):
 
         self.mailbox = Mailbox.objects.create(from_email='from@example.com')
 
-        self.test_account = os.environ['EMAIL_ACCOUNT']
-        self.test_password = os.environ['EMAIL_PASSWORD']
-        self.test_smtp_server = os.environ['EMAIL_SMTP_SERVER']
+        self.test_account = os.environ.get('EMAIL_ACCOUNT')
+        self.test_password = os.environ.get('EMAIL_PASSWORD')
+        self.test_smtp_server = os.environ.get('EMAIL_SMTP_SERVER')
         self.test_from_email = 'nobody@nowhere.com'
 
         self.maximum_wait_seconds = 60 * 5
diff --git a/django_mailbox/tests/test_integration_imap.py b/django_mailbox/tests/test_integration_imap.py
index 261c159..96c3a6e 100644
--- a/django_mailbox/tests/test_integration_imap.py
+++ b/django_mailbox/tests/test_integration_imap.py
@@ -15,9 +15,26 @@ __all__ = ['TestImap']
 class TestImap(EmailMessageTestCase):
     def setUp(self):
         super(TestImap, self).setUp()
+
         self.test_imap_server = (
-            os.environ['EMAIL_IMAP_SERVER']
+            os.environ.get('EMAIL_IMAP_SERVER')
         )
+
+        required_settings = [
+            self.test_imap_server,
+            self.test_account,
+            self.test_password,
+            self.test_smtp_server,
+            self.test_from_email,
+        ]
+        if not all(required_settings):
+            self.skipTest(
+                "Integration tests are not available without having "
+                "the the following environment variables set: "
+                "EMAIL_ACCOUNT, EMAIL_PASSWORD, EMAIL_SMTP_SERVER, "
+                "EMAIL_IMAP_SERVER."
+            )
+
         self.mailbox = Mailbox.objects.create(
             name='Integration Test Imap',
             uri=self.get_connection_string()
diff --git a/setup.py b/setup.py
index 3023819..8db714b 100755
--- a/setup.py
+++ b/setup.py
@@ -5,6 +5,7 @@ from django_mailbox import __version__ as version_string
 tests_require = [
     'django',
     'mock',
+    'unittest2',
 ]
 
 gmail_oauth2_require = [