--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hgext3rd/fastimport/vendor/python_fastimport/tests/test_helpers.py	Tue Jan 19 22:56:34 2021 +0000
@@ -0,0 +1,55 @@
+# Copyright (C) 2009 Canonical Ltd
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+"""Test the helper functions."""
+
+import unittest
+
+from fastimport import (
+    helpers,
+    )
+
+
+class TestCommonDirectory(unittest.TestCase):
+
+    def test_no_paths(self):
+        c = helpers.common_directory(None)
+        self.assertEqual(c, None)
+        c = helpers.common_directory([])
+        self.assertEqual(c, None)
+
+    def test_one_path(self):
+        c = helpers.common_directory([b'foo'])
+        self.assertEqual(c, b'')
+        c = helpers.common_directory([b'foo/'])
+        self.assertEqual(c, b'foo/')
+        c = helpers.common_directory([b'foo/bar'])
+        self.assertEqual(c, b'foo/')
+
+    def test_two_paths(self):
+        c = helpers.common_directory([b'foo', b'bar'])
+        self.assertEqual(c, b'')
+        c = helpers.common_directory([b'foo/', b'bar'])
+        self.assertEqual(c, b'')
+        c = helpers.common_directory([b'foo/', b'foo/bar'])
+        self.assertEqual(c, b'foo/')
+        c = helpers.common_directory([b'foo/bar/x', b'foo/bar/y'])
+        self.assertEqual(c, b'foo/bar/')
+        c = helpers.common_directory([b'foo/bar/aa_x', b'foo/bar/aa_y'])
+        self.assertEqual(c, b'foo/bar/')
+
+    def test_lots_of_paths(self):
+        c = helpers.common_directory([b'foo/bar/x', b'foo/bar/y', b'foo/bar/z'])
+        self.assertEqual(c, b'foo/bar/')