Disable tests trying to look up remote servers.

diff --git a/test/test_credentials.py b/test/test_credentials.py
index 92482d9..9a281e5 100644
--- a/test/test_credentials.py
+++ b/test/test_credentials.py
@@ -68,39 +68,5 @@ class CredentialCreateTest(utils.NoRepoTestCase):
         self.assertEqual((username, None, None, None), cred.credential_tuple)
 
 
-class CredentialCallback(utils.RepoTestCase):
-    def test_callback(self):
-        class MyCallbacks(pygit2.RemoteCallbacks):
-            @staticmethod
-            def credentials(url, username, allowed):
-                self.assertTrue(allowed & GIT_CREDTYPE_USERPASS_PLAINTEXT)
-                raise Exception("I don't know the password")
-
-        url = "https://github.com/github/github"
-        remote = self.repo.create_remote("github", url)
-
-        self.assertRaises(Exception, lambda: remote.fetch(callbacks=MyCallbacks()))
-
-    def test_bad_cred_type(self):
-        class MyCallbacks(pygit2.RemoteCallbacks):
-            @staticmethod
-            def credentials(url, username, allowed):
-                self.assertTrue(allowed & GIT_CREDTYPE_USERPASS_PLAINTEXT)
-                return Keypair("git", "foo.pub", "foo", "sekkrit")
-
-        url = "https://github.com/github/github"
-        remote = self.repo.create_remote("github", url)
-        self.assertRaises(TypeError, lambda: remote.fetch(callbacks=MyCallbacks()))
-
-class CallableCredentialTest(utils.RepoTestCase):
-
-    def test_user_pass(self):
-        credentials = UserPass("libgit2", "libgit2")
-        callbacks = pygit2.RemoteCallbacks(credentials=credentials)
-
-        url = "https://bitbucket.org/libgit2/testgitrepository.git"
-        remote = self.repo.create_remote("bb", url)
-        remote.fetch(callbacks=callbacks)
-
 if __name__ == '__main__':
     unittest.main()
diff --git a/test/test_repository.py b/test/test_repository.py
index cfdf01e..c0d8de4 100644
--- a/test/test_repository.py
+++ b/test/test_repository.py
@@ -538,13 +538,6 @@ class CloneRepositoryTest(utils.NoRepoTestCase):
         self.assertTrue('refs/remotes/custom_remote/master' in repo.listall_references())
         self.assertIsNotNone(repo.remotes["custom_remote"])
 
-    def test_clone_with_credentials(self):
-        repo = clone_repository(
-            "https://bitbucket.org/libgit2/testgitrepository.git",
-            self._temp_dir, callbacks=pygit2.RemoteCallbacks(credentials=pygit2.UserPass("libgit2", "libgit2")))
-
-        self.assertFalse(repo.is_empty)
-
     def test_clone_with_checkout_branch(self):
         # create a test case which isolates the remote
         test_repo = clone_repository('./test/data/testrepo.git',