diff --git a/fdroidserver/nightly.py b/fdroidserver/nightly.py
index 3eb4333c..30161c1d 100644
--- a/fdroidserver/nightly.py
+++ b/fdroidserver/nightly.py
@@ -203,6 +203,15 @@ def get_repo_base_url(clone_url: str, repo_git_base: str, force_type: Optional[s
     sys.exit(1)
 
 
+def clone_git_repo(clone_url, git_mirror_path):
+    logging.debug(_('cloning {url}').format(url=clone_url))
+    vcs = common.getvcs('git', clone_url, git_mirror_path)
+    p = vcs.git(['clone', '--', vcs.remote, str(vcs.local)])
+    if p.returncode != 0:
+        print('WARNING: only public git repos are supported!')
+        raise VCSException('git clone %s failed:' % clone_url, p.output)
+
+
 def main():
     """Deploy to F-Droid repository or generate SSH private key from keystore.
 
@@ -338,12 +347,7 @@ def main():
         git_mirror_repodir = os.path.join(git_mirror_fdroiddir, 'repo')
         git_mirror_metadatadir = os.path.join(git_mirror_fdroiddir, 'metadata')
         if not os.path.isdir(git_mirror_repodir):
-            logging.debug(_('cloning {url}').format(url=clone_url))
-            vcs = common.getvcs('git', clone_url, git_mirror_path)
-            p = vcs.git(['clone', '--', vcs.remote, str(vcs.local)])
-            if p.returncode != 0:
-                print('WARNING: only public git repos are supported!')
-                raise VCSException('git clone %s failed:' % clone_url, p.output)
+            clone_git_repo(clone_url, git_mirror_repodir)
         if not os.path.isdir(git_mirror_repodir):
             os.makedirs(git_mirror_repodir, mode=0o755)
 
diff --git a/tests/test_nightly.py b/tests/test_nightly.py
index 750a22fc..681df96d 100755
--- a/tests/test_nightly.py
+++ b/tests/test_nightly.py
@@ -192,6 +192,29 @@ class NightlyTest(unittest.TestCase):
             with self.assertRaises(exception.VCSException):
                 nightly.main()
 
+    def test_clone_git_repo(self):
+        os.chdir(self.testdir)
+        common.options = Options
+        d = 'fakeappid'
+        nightly.clone_git_repo('https://gitlab.com/fdroid/ci-test-tiny-repo.git', d)
+        self.assertTrue(os.path.isdir(Path(d) / '.git'))
+
+    def test_clone_git_repo_fails_on_gitlab_password_prompt(self):
+        os.chdir(self.testdir)
+        common.options = Options
+        d = 'shouldnotbecreated'
+        with self.assertRaises(exception.VCSException):
+            nightly.clone_git_repo(f'https://gitlab.com/{d}/{d}.git', d)
+        self.assertFalse(os.path.isdir(Path(d)))
+
+    def test_clone_git_repo_fails_on_github_password_prompt(self):
+        os.chdir(self.testdir)
+        common.options = Options
+        d = 'shouldnotbecreated'
+        with self.assertRaises(exception.VCSException):
+            nightly.clone_git_repo(f'https://github.com/{d}/{d}.git', d)
+        self.assertFalse(os.path.isdir(Path(d)))
+
     def _put_fdroid_in_args(self, args):
         """Find fdroid command that belongs to this source code tree"""
         fdroid = os.path.join(basedir.parent, 'fdroid')