diff --git a/swh/loader/dir/tests/test_git.py b/swh/loader/dir/tests/test_git.py
new file mode 100644
index 0000000..0918e21
--- /dev/null
+++ b/swh/loader/dir/tests/test_git.py
@@ -0,0 +1,70 @@
+# Copyright (C) 2015  The Software Heritage developers
+# See the AUTHORS file at the top-level directory of this distribution
+# License: GNU General Public License version 3, or any later version
+# See top-level LICENSE file for more information
+
+import unittest
+
+from nose.tools import istest
+
+from swh.loader.dir import git
+
+
+class GitHashlib(unittest.TestCase):
+
+    def setUp(self):
+        self.blob_data = b'42\n'
+
+        self.tree_data = b''.join([b'40000 barfoo\0',
+                                   bytes.fromhex('c3020f6bf135a38c6df3afeb5fb38232c5e07087'),
+                                   b'100644 blah\0',
+                                   bytes.fromhex('63756ef0df5e4f10b6efa33cfe5c758749615f20'),
+                                   b'100644 hello\0',
+                                   bytes.fromhex('907b308167f0880fb2a5c0e1614bb0c7620f9dc3')])
+
+        self.commit_data = """tree 1c61f7259dcb770f46b194d941df4f08ff0a3970
+author Antoine R. Dumont (@ardumont) <antoine.romain.dumont@gmail.com> 1444054085 +0200
+committer Antoine R. Dumont (@ardumont) <antoine.romain.dumont@gmail.com> 1444054085 +0200
+
+initial
+""".encode('utf-8')
+
+        self.checksums = {
+            'blob_sha1_git': bytes.fromhex('d81cc0710eb6cf9efd5b920a8453e1'
+                                              'e07157b6cd'),
+            'tree_sha1_git': bytes.fromhex('ac212302c45eada382b27bfda795db'
+                                           '121dacdb1c'),
+            'commit_sha1_git': bytes.fromhex('e960570b2e6e2798fa4cfb9af2c399'
+                                               'd629189653'),
+        }
+
+    @istest
+    def unknown_header_type(self):
+        with self.assertRaises(ValueError) as cm:
+            git.hashdata(b'any-data', 'some-unknown-type')
+
+        self.assertIn('Only supported types', cm.exception.args[0])
+
+    @istest
+    def hashdata_content(self):
+        # when
+        checksums = git.hashdata(self.blob_data, 'blob')
+
+        # then
+        self.assertEqual(checksums['sha1_git'], self.checksums['blob_sha1_git'])
+
+    @istest
+    def hashdata_tree(self):
+        # when
+        checksums = git.hashdata(self.tree_data, 'tree')
+
+        # then
+        self.assertEqual(checksums['sha1_git'], self.checksums['tree_sha1_git'])
+
+    @istest
+    def hashdata_revision(self):
+        # when
+        checksums = git.hashdata(self.commit_data, 'commit')
+
+        # then
+        self.assertEqual(checksums['sha1_git'], self.checksums['commit_sha1_git'])