diff --git a/swh/model/tests/test_git.py b/swh/model/tests/test_git.py
index 10003e13eedc09e8340447da899a01ca291a5bf8..b39a3357cec32ac2cba77ecbff7808da04c75c54 100644
--- a/swh/model/tests/test_git.py
+++ b/swh/model/tests/test_git.py
@@ -243,3 +243,347 @@ class GitHashFromScratch(GitHashWalkArborescenceTree):
 
         # should give us the same checksums as the second round
         self.assertEquals(actual_hashes, expected_hashes)
+
+
+class TestObjectsPerType(unittest.TestCase):
+    def setUp(self):
+        self.objects = {
+            b'/tmp/tmp7w3oi_j8': {
+                'children': {b'/tmp/tmp7w3oi_j8/sample-folder'},
+                'checksums': {
+                    'type': git.GitType.TREE,
+                    'name': b'tmp7w3oi_j8',
+                    'sha1_git': b'\xa7A\xfcM\x96\x8c{\x8e<\x94\xff\x86\xe7\x04\x80\xc5\xc7\xe5r\xa9',  # noqa
+                    'path': b'/tmp/tmp7w3oi_j8',
+                    'perms': git.GitPerm.TREE
+                },
+            },
+            b'/tmp/tmp7w3oi_j8/sample-folder': {
+                'children': {
+                    b'/tmp/tmp7w3oi_j8/sample-folder/empty-folder',
+                    b'/tmp/tmp7w3oi_j8/sample-folder/link-to-binary',
+                    b'/tmp/tmp7w3oi_j8/sample-folder/link-to-another-quote',
+                    b'/tmp/tmp7w3oi_j8/sample-folder/link-to-foo',
+                    b'/tmp/tmp7w3oi_j8/sample-folder/some-binary',
+                    b'/tmp/tmp7w3oi_j8/sample-folder/bar',
+                    b'/tmp/tmp7w3oi_j8/sample-folder/foo',
+                },
+                'checksums': {
+                    'type': git.GitType.TREE,
+                    'name': b'sample-folder',
+                    'sha1_git': b'\xe8\xb0\xf1Fj\xf8`\x8c\x8a?\xb9\x87\x9d\xb1r\xb8\x87\xe8\x07Y',  # noqa
+                    'path': b'/tmp/tmp7w3oi_j8/sample-folder',
+                    'perms': git.GitPerm.TREE}
+            },
+            b'/tmp/tmp7w3oi_j8/sample-folder/empty-folder': {
+                'children': {},
+                'checksums': {
+                    'type': git.GitType.TREE,
+                    'name': b'empty-folder',
+                    'sha1_git': b'K\x82]\xc6B\xcbn\xb9\xa0`\xe5K\xf8\xd6\x92\x88\xfb\xeeI\x04',  # noqa
+                    'path': b'/tmp/tmp7w3oi_j8/sample-folder/empty-folder',
+                    'perms': git.GitPerm.TREE
+                }
+            },
+            b'/tmp/tmp7w3oi_j8/sample-folder/link-to-binary': {
+                'checksums': {
+                    'name': b'link-to-binary',
+                    'sha1': b'\xd0$\x87\x14\x94\x8b:H\xa2T8#*o\x99\xf01\x8fY\xf1',  # noqa
+                    'data': b'some-binary',
+                    'sha1_git': b'\xe8kE\xe58\xd9\xb6\x88\x8c\x96\x9c\x89\xfb\xd2*\x85\xaa\x0e\x03f',  # noqa
+                    'path': b'/tmp/tmp7w3oi_j8/sample-folder/link-to-binary',
+                    'sha256': b'\x14\x12n\x97\xd8?}&\x1cZh\x89\xce\xe76\x19w\x0f\xf0\x9e@\xc5I\x86\x85\xab\xa7E\xbe\x88.\xff',  # noqa
+                    'perms': git.GitPerm.LINK,
+                    'type': git.GitType.BLOB,
+                    'length': 11
+                }
+            },
+            b'/tmp/tmp7w3oi_j8/sample-folder/link-to-another-quote': {
+                'checksums': {
+                    'name': b'link-to-another-quote',
+                    'sha1': b'\xcb\xee\xd1^yY\x9c\x90\xdes\x83\xf4 \xfe\xd7\xac\xb4\x8e\xa1q',  # noqa
+                    'data': b'bar/barfoo/another-quote.org',
+                    'sha1_git': b'}\\\x08\x11\x1e!\xc8\xa9\xf7\x15@\x93\x99\x98U\x16\x837_\xad',  # noqa
+                    'path': b'/tmp/tmp7w3oi_j8/sample-folder/link-to-another-quote',  # noqa
+                    'sha256': b'\xe6\xe1}\x07\x93\xaau\n\x04@\xeb\x9a\xd5\xb8\x0b%\x80vc~\xf0\xfbh\xf3\xac.Y\xe4\xb9\xac;\xa6',  # noqa
+                    'perms': git.GitPerm.LINK,
+                    'type': git.GitType.BLOB,
+                    'length': 28
+                }
+            },
+            b'/tmp/tmp7w3oi_j8/sample-folder/link-to-foo': {
+                'checksums': {
+                    'name': b'link-to-foo',
+                    'sha1': b'\x0b\xee\xc7\xb5\xea?\x0f\xdb\xc9]\r\xd4\x7f<[\xc2u\xda\x8a3',  # noqa
+                    'data': b'foo',
+                    'sha1_git': b'\x19\x10(\x15f=#\xf8\xb7ZG\xe7\xa0\x19e\xdc\xdc\x96F\x8c',  # noqa
+                    'path': b'/tmp/tmp7w3oi_j8/sample-folder/link-to-foo',
+                    'sha256': b',\xb4kh\xff\xc6\x8f\xf9\x9bE<\x1d0A4\x13B-pd\x83\xbf\xa0\xf9\x8a^\x88bf\xe7\xae',  # noqa
+                    'perms': git.GitPerm.LINK,
+                    'type': git.GitType.BLOB,
+                    'length': 3
+                }
+            },
+            b'/tmp/tmp7w3oi_j8/sample-folder/some-binary': {
+                'checksums': {
+                    'name': b'some-binary',
+                    'sha1': b'\x0b\xbc\x12\xd7\xf4\xa2\xa1[\x14=\xa8F\x17\xd9\\\xb2#\xc9\xb2<',  # noqa
+                    'sha1_git': b'hv\x95y\xc3\xea\xad\xbeUSy\xb9\xc3S\x8ef(\xba\xe1\xeb',  # noqa
+                    'path': b'/tmp/tmp7w3oi_j8/sample-folder/some-binary',
+                    'sha256': b'\xba\xc6P\xd3Jv8\xbb\n\xebSBdm$\xe3\xb9\xadkD\xc9\xb3\x83b\x1f\xaaH+\x99\n6}',  # noqa
+                    'perms': git.GitPerm.EXEC,
+                    'type': git.GitType.BLOB,
+                    'length': 5}
+            },
+            b'/tmp/tmp7w3oi_j8/sample-folder/bar': {
+                'children': {b'/tmp/tmp7w3oi_j8/sample-folder/bar/barfoo'},
+                'checksums': {'type': git.GitType.TREE,
+                              'name': b'bar',
+                              'sha1_git': b'<\x1fW\x83\x94\xf4b?t\xa0\xba\x7f\xe7ar\x9fY\xfcn\xc4',  # noqa
+                              'path': b'/tmp/tmp7w3oi_j8/sample-folder/bar',
+                              'perms': git.GitPerm.TREE},
+            },
+            b'/tmp/tmp7w3oi_j8/sample-folder/bar/barfoo': {
+                'children': {b'/tmp/tmp7w3oi_j8/sample-folder/bar/barfoo/another-quote.org'},  # noqa
+                'checksums': {'type': git.GitType.TREE,
+                              'name': b'barfoo',
+                              'sha1_git': b'\xc3\x02\x0fk\xf15\xa3\x8cm\xf3\xaf\xeb_\xb3\x822\xc5\xe0p\x87',  # noqa
+                              'path': b'/tmp/tmp7w3oi_j8/sample-folder/bar/barfoo',  # noqa
+                              'perms': git.GitPerm.TREE},
+            },
+            b'/tmp/tmp7w3oi_j8/sample-folder/bar/barfoo/another-quote.org': {
+                'checksums': {'name': b'another-quote.org',
+                              'sha1': b'\x90\xa6\x13\x8b\xa5\x99\x15&\x1e\x17\x99H8j\xa1\xcc*\xa9"\n',  # noqa
+                              'sha1_git': b'\x136\x93\xb1%\xba\xd2\xb4\xac1\x855\xb8I\x01\xeb\xb1\xf6\xb68',  # noqa
+                              'path': b'/tmp/tmp7w3oi_j8/sample-folder/bar/barfoo/another-quote.org',  # noqa
+                              'sha256': b'=\xb5\xae\x16\x80U\xbc\xd9:M\x08(]\xc9\x9f\xfe\xe2\x883\x03\xb2?\xac^\xab\x85\x02s\xa8\xeaUF',  # noqa
+                              'perms': git.GitPerm.BLOB,
+                              'type': git.GitType.BLOB,
+                              'length': 72}
+            },
+            b'/tmp/tmp7w3oi_j8/sample-folder/foo': {
+                'children': {
+                    b'/tmp/tmp7w3oi_j8/sample-folder/foo/barfoo',
+                    b'/tmp/tmp7w3oi_j8/sample-folder/foo/rel-link-to-barfoo',
+                    b'/tmp/tmp7w3oi_j8/sample-folder/foo/quotes.md',
+                },
+                'checksums': {'type': git.GitType.TREE,
+                              'name': b'foo',
+                              'sha1_git': b'+A\xc4\x0f\r\x1f\xbf\xfc\xba\x12I}\xb7\x1f\xba\x83\xfc\xca\x96\xe5',  # noqa
+                              'path': b'/tmp/tmp7w3oi_j8/sample-folder/foo',
+                              'perms': git.GitPerm.TREE}
+            },
+            b'/tmp/tmp7w3oi_j8/sample-folder/foo/barfoo': {
+                'checksums': {'name': b'barfoo',
+                              'sha1': b'\x90W\xeem\x01bPn\x01\xc4\xd9\xd5E\x9az\xdd\x1f\xed\xac7',  # noqa
+                              'data': b'bar/barfoo',
+                              'sha1_git': b'\x81\x85\xdf\xb2\xc0\xc2\xc5\x97\xd1ou\xa8\xa0\xc3vhV|=~',  # noqa
+                              'path': b'/tmp/tmp7w3oi_j8/sample-folder/foo/barfoo',  # noqa
+                              'sha256': b')\xad?W%2\x1b\x94\x032\xc7\x8e@6\x01\xaf\xffa\xda\xea\x85\xe9\xc8\x0bJpc\xb6\x88~\xadh',  # noqa
+                              'perms': git.GitPerm.LINK,
+                              'type': git.GitType.BLOB,
+                              'length': 10}
+            },
+            b'/tmp/tmp7w3oi_j8/sample-folder/foo/rel-link-to-barfoo': {
+                'checksums': {'name': b'rel-link-to-barfoo',
+                              'sha1': b'\xdcQ"\x1d0\x8f:\xeb\'T\xdbH9\x1b\x85h|(i\xf4',  # noqa
+                              'data': b'../bar/barfoo',
+                              'sha1_git': b'\xac\xac2m\xddc\xb0\xbcp\x84\x06Y\xd4\xacCa\x94\x84\xe6\x9f',  # noqa
+                              'path': b'/tmp/tmp7w3oi_j8/sample-folder/foo/rel-link-to-barfoo',  # noqa
+                              'sha256': b'\x80\x07\xd2\r\xb2\xaf@C_B\xdd\xefK\x8a\xd7k\x80\xad\xbe\xc2k$\x9f\xdf\x04s5?\x8d\x99\xdf\x08',  # noqa
+                              'perms': git.GitPerm.LINK,
+                              'type': git.GitType.BLOB,
+                              'length': 13}
+            },
+            b'/tmp/tmp7w3oi_j8/sample-folder/foo/quotes.md': {
+                'checksums': {'name': b'quotes.md',
+                              'sha1': b'\x1b\xf0\xbbr\x1a\xc9,x18\xa1\x9b\x13\xc0\xeb=t\x1c\xbf\xad\xeb\xfc',  # noqa
+                              'sha1_git': b'|LW\xba\x9f\xf4\x96\xad\x17\x9b\x8fe\xb1\xd2\x86\xed\xbd\xa3L\x9a',  # noqa
+                              'path': b'/tmp/tmp7w3oi_j8/sample-folder/foo/quotes.md',  # noqa
+                              'sha256': b'\xca\xca\x94*\xed\xa7\xb3\x08\x85\x9e\xb5o\x90\x9e\xc9m\x07\xa4\x99I\x16\x90\xc4S\xf7;\x98\x00\xa9;\x16Y',  # noqa
+                              'perms': git.GitPerm.BLOB,
+                              'type': git.GitType.BLOB,
+                              'length': 66}
+            },
+        }
+
+    @istest
+    def objects_per_type_blob(self):
+        # given
+        expected_blobs = [
+            {
+                'name': b'another-quote.org',
+                'sha1': b'\x90\xa6\x13\x8b\xa5\x99\x15&\x1e\x17\x99H8j\xa1\xcc*\xa9"\n',  # noqa
+                'sha1_git': b'\x136\x93\xb1%\xba\xd2\xb4\xac1\x855\xb8I\x01\xeb\xb1\xf6\xb68',  # noqa
+                'path': b'/tmp/tmp7w3oi_j8/sample-folder/bar/barfoo/another-quote.org',  # noqa
+                'sha256': b'=\xb5\xae\x16\x80U\xbc\xd9:M\x08(]\xc9\x9f\xfe\xe2\x883\x03\xb2?\xac^\xab\x85\x02s\xa8\xeaUF',  # noqa
+                'perms': git.GitPerm.BLOB,
+                'type': git.GitType.BLOB,
+                'length': 72
+            },
+            {
+                'name': b'link-to-binary',
+                'sha1': b'\xd0$\x87\x14\x94\x8b:H\xa2T8#*o\x99\xf01\x8fY\xf1',
+                'data': b'some-binary',
+                'sha1_git': b'\xe8kE\xe58\xd9\xb6\x88\x8c\x96\x9c\x89\xfb\xd2*\x85\xaa\x0e\x03f',  # noqa
+                'path': b'/tmp/tmp7w3oi_j8/sample-folder/link-to-binary',
+                'sha256': b'\x14\x12n\x97\xd8?}&\x1cZh\x89\xce\xe76\x19w\x0f\xf0\x9e@\xc5I\x86\x85\xab\xa7E\xbe\x88.\xff',  # noqa
+                'perms': git.GitPerm.LINK,
+                'type': git.GitType.BLOB,
+                'length': 11
+            },
+            {
+                'name': b'link-to-another-quote',
+                'sha1': b'\xcb\xee\xd1^yY\x9c\x90\xdes\x83\xf4 \xfe\xd7\xac\xb4\x8e\xa1q',  # noqa
+                'data': b'bar/barfoo/another-quote.org',
+                'sha1_git': b'}\\\x08\x11\x1e!\xc8\xa9\xf7\x15@\x93\x99\x98U\x16\x837_\xad',  # noqa
+                'path': b'/tmp/tmp7w3oi_j8/sample-folder/link-to-another-quote',  # noqa
+                'sha256': b'\xe6\xe1}\x07\x93\xaau\n\x04@\xeb\x9a\xd5\xb8\x0b%\x80vc~\xf0\xfbh\xf3\xac.Y\xe4\xb9\xac;\xa6',  # noqa
+                'perms': git.GitPerm.LINK,
+                'type': git.GitType.BLOB,
+                'length': 28
+            },
+            {
+                'name': b'link-to-foo',
+                'sha1': b'\x0b\xee\xc7\xb5\xea?\x0f\xdb\xc9]\r\xd4\x7f<[\xc2u\xda\x8a3',  # noqa
+                'data': b'foo',
+                'sha1_git': b'\x19\x10(\x15f=#\xf8\xb7ZG\xe7\xa0\x19e\xdc\xdc\x96F\x8c',  # noqa
+                'path': b'/tmp/tmp7w3oi_j8/sample-folder/link-to-foo',
+                'sha256': b'\xb4kh\xff\xc6\x8f\xf9\x9bE<\x1d0A4\x13B-pd\x83\xbf\xa0\xf9\x8a^\x88bf\xe7\xae',  # noqa
+                'perms': git.GitPerm.LINK,
+                'type': git.GitType.BLOB,
+                'length': 3
+            },
+            {
+                'name': b'some-binary',
+                'sha1': b'\x0b\xbc\x12\xd7\xf4\xa2\xa1[\x14=\xa8F\x17\xd9\\\xb2#\xc9\xb2<',  # noqa
+                'sha1_git': b'hv\x95y\xc3\xea\xad\xbeUSy\xb9\xc3S\x8ef(\xba\xe1\xeb',  # noqa
+                'path': b'/tmp/tmp7w3oi_j8/sample-folder/some-binary',
+                'sha256': b'\xba\xc6P\xd3Jv8\xbb\n\xebSBdm$\xe3\xb9\xadkD\xc9\xb3\x83b\x1f\xaaH+\x99\n6}',  # noqa
+                'perms': git.GitPerm.EXEC,
+                'type': git.GitType.BLOB,
+                'length': 5
+            },
+            {
+                'name': b'barfoo',
+                'sha1': b'\x90W\xeem\x01bPn\x01\xc4\xd9\xd5E\x9az\xdd\x1f\xed\xac7',  # noqa
+                'data': b'bar/barfoo',
+                'sha1_git': b'\x81\x85\xdf\xb2\xc0\xc2\xc5\x97\xd1ou\xa8\xa0\xc3vhV|=~',  # noqa
+                'path': b'/tmp/tmp7w3oi_j8/sample-folder/foo/barfoo',
+                'sha256': b')\xad?W%2\x1b\x94\x032\xc7\x8e@6\x01\xaf\xffa\xda\xea\x85\xe9\xc8\x0bJpc\xb6\x88~\xadh',  # noqa
+                'perms': git.GitPerm.LINK,
+                'type': git.GitType.BLOB,
+                'length': 10
+            },
+            {
+                'name': b'rel-link-to-barfoo',
+                'sha1': b'\xdcQ"\x1d0\x8f:\xeb\'T\xdbH9\x1b\x85h|(i\xf4',
+                'data': b'../bar/barfoo',
+                'sha1_git': b'\xac\xac2m\xddc\xb0\xbcp\x84\x06Y\xd4\xacCa\x94\x84\xe6\x9f',  # noqa
+                'path': b'/tmp/tmp7w3oi_j8/sample-folder/foo/rel-link-to-barfoo',  # noqa
+                'sha256': b'\x80\x07\xd2\r\xb2\xaf@C_B\xdd\xefK\x8a\xd7k\x80\xad\xbe\xc2k$\x9f\xdf\x04s5?\x8d\x99\xdf\x08',  # noqa
+                'perms': git.GitPerm.LINK,
+                'type': git.GitType.BLOB,
+                'length': 13
+            },
+            {
+                'name': b'quotes.md',
+                'sha1': b'\x1b\xf0\xbbr\x1a\xc9,x18\xa1\x9b\x13\xc0\xeb=t\x1c\xbf\xad\xeb\xfc',  # noqa
+                'sha1_git': b'|LW\xba\x9f\xf4\x96\xad\x17\x9b\x8fe\xb1\xd2\x86\xed\xbd\xa3L\x9a',  # noqa
+                'path': b'/tmp/tmp7w3oi_j8/sample-folder/foo/quotes.md',
+                'sha256': b'\xca\xca\x94*\xed\xa7\xb3\x08\x85\x9e\xb5o\x90\x9e\xc9m\x07\xa4\x99I\x16\x90\xc4S\xf7;\x98\x00\xa9;\x16Y',  # noqa
+                'perms': git.GitPerm.BLOB,
+                'type': git.GitType.BLOB,
+                'length': 66
+            },
+        ]
+
+        expected_sha1_blobs = set(
+            ((c['sha1_git'], git.GitType.BLOB) for c in expected_blobs))
+
+        # when
+        actual_sha1_blobs = set(
+            ((c['sha1_git'], c['type'])
+             for c in git.objects_per_type(git.GitType.BLOB, self.objects)))
+
+        # then
+        self.assertEqual(actual_sha1_blobs, expected_sha1_blobs)
+
+    @istest
+    def objects_per_type_tree(self):
+        def __children_hashes(path, objects=self.objects):
+            return set((c['sha1_git']
+                       for c in git.children_hashes(
+                           objects[path]['children'], objects)))
+
+        expected_trees = [
+            {
+                'type': git.GitType.TREE,
+                'name': b'tmp7w3oi_j8',
+                'sha1_git': b'\xa7A\xfcM\x96\x8c{\x8e<\x94\xff\x86\xe7\x04\x80\xc5\xc7\xe5r\xa9',  # noqa
+                'path': b'/tmp/tmp7w3oi_j8',
+                'perms': git.GitPerm.TREE,
+                # we only add children's sha1_git here, in reality,
+                # it's a full dict of hashes.
+                'children': __children_hashes(b'/tmp/tmp7w3oi_j8')
+            },
+            {
+                'type': git.GitType.TREE,
+                'name': b'sample-folder',
+                'sha1_git': b'\xe8\xb0\xf1Fj\xf8`\x8c\x8a?\xb9\x87\x9d\xb1r\xb8\x87\xe8\x07Y',  # noqa
+                'path': b'/tmp/tmp7w3oi_j8/sample-folder',
+                'perms': git.GitPerm.TREE,
+                'children': __children_hashes(
+                    b'/tmp/tmp7w3oi_j8/sample-folder')
+            },
+            {
+                'type': git.GitType.TREE,
+                'name': b'empty-folder',
+                'sha1_git': b'K\x82]\xc6B\xcbn\xb9\xa0`\xe5K\xf8\xd6\x92\x88\xfb\xeeI\x04',  # noqa
+                'path': b'/tmp/tmp7w3oi_j8/sample-folder/empty-folder',
+                'perms': git.GitPerm.TREE,
+                'children': __children_hashes(
+                    b'/tmp/tmp7w3oi_j8/sample-folder/empty-folder')
+            },
+            {
+                'type': git.GitType.TREE,
+                'name': b'bar',
+                'sha1_git': b'<\x1fW\x83\x94\xf4b?t\xa0\xba\x7f\xe7ar\x9fY\xfcn\xc4',  # noqa
+                'path': b'/tmp/tmp7w3oi_j8/sample-folder/bar',
+                'perms': git.GitPerm.TREE,
+                'children': __children_hashes(
+                    b'/tmp/tmp7w3oi_j8/sample-folder/bar')
+            },
+            {
+                'type': git.GitType.TREE,
+                'name': b'barfoo',
+                'sha1_git': b'\xc3\x02\x0fk\xf15\xa3\x8cm\xf3\xaf\xeb_\xb3\x822\xc5\xe0p\x87',  # noqa
+                'path': b'/tmp/tmp7w3oi_j8/sample-folder/bar/barfoo',
+                'perms': git.GitPerm.TREE,
+                'children': __children_hashes(
+                    b'/tmp/tmp7w3oi_j8/sample-folder/bar/barfoo'),
+            },
+            {
+                'type': git.GitType.TREE,
+                'name': b'foo',
+                'sha1_git': b'+A\xc4\x0f\r\x1f\xbf\xfc\xba\x12I}\xb7\x1f\xba\x83\xfc\xca\x96\xe5',  # noqa
+                'path': b'/tmp/tmp7w3oi_j8/sample-folder/foo',
+                'perms': git.GitPerm.TREE,
+                'children': __children_hashes(
+                    b'/tmp/tmp7w3oi_j8/sample-folder/foo')
+            },
+        ]
+        expected_sha1_trees = list(
+            ((c['sha1_git'], git.GitType.TREE, c['children'])
+             for c in expected_trees))
+
+        print(expected_sha1_trees)
+
+        # when
+        actual_sha1_trees = list(
+            ((c['sha1_git'], c['type'], __children_hashes(c['path']))
+             for c in git.objects_per_type(git.GitType.TREE, self.objects)))
+
+        self.assertEquals(len(actual_sha1_trees), len(expected_sha1_trees))
+        for e in actual_sha1_trees:
+            self.assertTrue(e in expected_sha1_trees)