nightly: fail if *-nightly git repo is not publicly available

tests/nightly.TestCase

@@ -23,7 +23,7 @@ print('localmodule: ' + localmodule)
 if localmodule not in sys.path:
     sys.path.insert(0, localmodule)
 
-from fdroidserver import common, index, nightly
+from fdroidserver import common, exception, index, nightly
 
 
 DEBUG_KEYSTORE = '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'
@@ -151,6 +151,32 @@ class NightlyTest(unittest.TestCase):
         assert (dot_ssh / AOSP_TESTKEY_DEBUG_KEYSTORE_KEY_FILE_NAME).exists()
         assert (dot_ssh / (AOSP_TESTKEY_DEBUG_KEYSTORE_KEY_FILE_NAME + '.pub')).exists()
 
+    @patch('sys.argv', ['fdroid nightly', '--verbose'])
+    def test_private_or_non_existent_git_mirror(self):
+        """Test that this exits with an error when the git mirror repo won't work
+
+        Careful!  If the test environment is setup wrong, it can mess
+        up the local SSH files.
+
+        """
+        os.chdir(self.testdir)
+        with patch.dict(
+            os.environ,
+            {
+                'CI': 'true',
+                'CI_PROJECT_PATH': 'thisshouldneverexist/orthistoo',
+                'CI_PROJECT_URL': 'https://gitlab.com/thisshouldneverexist/orthistoo',
+                'DEBUG_KEYSTORE': DEBUG_KEYSTORE,
+                'GITLAB_USER_NAME': 'username',
+                'GITLAB_USER_EMAIL': 'username@example.com',
+                'HOME': str(self.testdir),
+                'PATH': os.getenv('PATH'),
+            },
+            clear=True,
+        ):
+            with self.assertRaises(exception.VCSException):
+                nightly.main()
+
     def _put_fdroid_in_args(self, args):
         """Find fdroid command that belongs to this source code tree"""
         fdroid = os.path.join(localmodule, 'fdroid')