diff --git a/tests/test_oauth2client_appengine.py b/tests/test_oauth2client_appengine.py
index f2f470f..90ee335 100644
--- a/tests/test_oauth2client_appengine.py
+++ b/tests/test_oauth2client_appengine.py
@@ -203,6 +203,30 @@
     q = parse_qs(response.headers['Location'].split('?', 1)[1])
     self.assertEqual('http://localhost/oauth2callback', q['redirect_uri'][0])
 
+  def test_storage_delete(self):
+    # An initial request to an oauth_required decorated path should be a
+    # redirect to start the OAuth dance.
+    response = self.app.get('/foo_path')
+    self.assertTrue(response.status.startswith('302'))
+
+    # Now simulate the callback to /oauth2callback.
+    response = self.app.get('/oauth2callback', {
+        'code': 'foo_access_code',
+        'state': 'foo_path',
+        })
+    self.assertEqual('http://localhost/foo_path', response.headers['Location'])
+    self.assertEqual(None, self.decorator.credentials)
+
+    # Now requesting the decorated path should work.
+    response = self.app.get('/foo_path')
+
+    # Invalidate the stored Credentials.
+    self.decorator.credentials.store.delete()
+
+    # Invalid Credentials should start the OAuth dance again.
+    response = self.app.get('/foo_path')
+    self.assertTrue(response.status.startswith('302'))
+
   def test_aware(self):
     # An initial request to an oauth_aware decorated path should not redirect.
     response = self.app.get('/bar_path')
diff --git a/tests/test_oauth2client_file.py b/tests/test_oauth2client_file.py
index 7ff1eeb..596a4b6 100644
--- a/tests/test_oauth2client_file.py
+++ b/tests/test_oauth2client_file.py
@@ -98,7 +98,6 @@
     self.assertEquals(data['_module'], OAuth2Credentials.__module__)
 
   def test_token_refresh(self):
-    # Write a file with a pickled OAuth2Credentials.
     access_token = 'foo'
     client_id = 'some_client_id'
     client_secret = 'cOuDdkfjxxnv+'
@@ -122,6 +121,27 @@
     credentials._refresh(lambda x: x)
     self.assertEquals(credentials.access_token, 'bar')
 
+  def test_credentials_delete(self):
+    access_token = 'foo'
+    client_id = 'some_client_id'
+    client_secret = 'cOuDdkfjxxnv+'
+    refresh_token = '1/0/a.df219fjls0'
+    token_expiry = datetime.datetime.utcnow()
+    token_uri = 'https://www.google.com/accounts/o8/oauth2/token'
+    user_agent = 'refresh_checker/1.0'
+
+    credentials = OAuth2Credentials(
+        access_token, client_id, client_secret,
+        refresh_token, token_expiry, token_uri,
+        user_agent)
+
+    s = Storage(FILENAME)
+    s.put(credentials)
+    credentials = s.get()
+    self.assertNotEquals(None, credentials)
+    s.delete()
+    credentials = s.get()
+    self.assertEquals(None, credentials)
 
   def test_access_token_credentials(self):
     access_token = 'foo'
@@ -205,6 +225,11 @@
     self.assertNotEquals(None, credentials)
     self.assertEquals('foo', credentials.access_token)
 
+    store.delete()
+    credentials = store.get()
+
+    self.assertEquals(None, credentials)
+
     if os.name == 'posix':
       self.assertEquals('0600', oct(stat.S_IMODE(os.stat(FILENAME).st_mode)))