dulwich/tests/test_objects.py

# test_objects.py -- tests for objects.py
# Copyright (C) 2007 James Westby <jw+debian@jameswestby.net>
#
# Dulwich is dual-licensed under the Apache License, Version 2.0 and the GNU
# General Public License as public by the Free Software Foundation; version 2.0
# or (at your option) any later version. You can redistribute it and/or
# modify it under the terms of either of these two licenses.
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
# You should have received a copy of the licenses; if not, see
# <http://www.gnu.org/licenses/> for a copy of the GNU General Public License
# and <http://www.apache.org/licenses/LICENSE-2.0> for a copy of the Apache
# License, Version 2.0.
#

"""Tests for git base objects."""

# TODO: Round-trip parse-serialize-parse and serialize-parse-serialize tests.

import datetime
import os
import stat
from contextlib import contextmanager
from io import BytesIO
from itertools import permutations

from dulwich.errors import ObjectFormatException
from dulwich.objects import (
    MAX_TIME,
    Blob,
    Commit,
    ShaFile,
    Tag,
    Tree,
    TreeEntry,
    _parse_tree_py,
    _sorted_tree_items_py,
    check_hexsha,
    check_identity,
    format_timezone,
    hex_to_filename,
    hex_to_sha,
    object_class,
    parse_timezone,
    parse_tree,
    pretty_format_tree_entry,
    sha_to_hex,
    sorted_tree_items,
)
from dulwich.tests.utils import (
    ext_functest_builder,
    functest_builder,
    make_commit,
    make_object,
)

from . import TestCase

a_sha = b"6f670c0fb53f9463760b7295fbb814e965fb20c8"
b_sha = b"2969be3e8ee1c0222396a5611407e4769f14e54b"
c_sha = b"954a536f7819d40e6f637f849ee187dd10066349"
tree_sha = b"70c190eb48fa8bbb50ddc692a17b44cb781af7f6"
tag_sha = b"71033db03a03c6a36721efcf1968dd8f8e0cf023"


class TestHexToSha(TestCase):
    def test_simple(self):
        self.assertEqual(b"\xab\xcd" * 10, hex_to_sha(b"abcd" * 10))

    def test_reverse(self):
        self.assertEqual(b"abcd" * 10, sha_to_hex(b"\xab\xcd" * 10))


class BlobReadTests(TestCase):
    """Test decompression of blobs."""

    def get_sha_file(self, cls, base, sha):
        dir = os.path.join(os.path.dirname(__file__), "..", "testdata", base)
        return cls.from_path(hex_to_filename(dir, sha))

    def get_blob(self, sha):
        """Return the blob named sha from the test data dir."""
        return self.get_sha_file(Blob, "blobs", sha)

    def get_tree(self, sha):
        return self.get_sha_file(Tree, "trees", sha)

    def get_tag(self, sha):
        return self.get_sha_file(Tag, "tags", sha)

    def commit(self, sha):
        return self.get_sha_file(Commit, "commits", sha)

    def test_decompress_simple_blob(self):
        b = self.get_blob(a_sha)
        self.assertEqual(b.data, b"test 1\n")
        self.assertEqual(b.sha().hexdigest().encode("ascii"), a_sha)

    def test_hash(self):
        b = self.get_blob(a_sha)
        self.assertEqual(hash(b.id), hash(b))

    def test_parse_empty_blob_object(self):
        sha = b"e69de29bb2d1d6434b8b29ae775ad8c2e48c5391"
        b = self.get_blob(sha)
        self.assertEqual(b.data, b"")
        self.assertEqual(b.id, sha)
        self.assertEqual(b.sha().hexdigest().encode("ascii"), sha)

    def test_create_blob_from_string(self):
        string = b"test 2\n"
        b = Blob.from_string(string)
        self.assertEqual(b.data, string)
        self.assertEqual(b.sha().hexdigest().encode("ascii"), b_sha)

    def test_legacy_from_file(self):
        b1 = Blob.from_string(b"foo")
        b_raw = b1.as_legacy_object()
        b2 = b1.from_file(BytesIO(b_raw))
        self.assertEqual(b1, b2)

    def test_legacy_from_file_compression_level(self):
        b1 = Blob.from_string(b"foo")
        b_raw = b1.as_legacy_object(compression_level=6)
        b2 = b1.from_file(BytesIO(b_raw))
        self.assertEqual(b1, b2)

    def test_chunks(self):
        string = b"test 5\n"
        b = Blob.from_string(string)
        self.assertEqual([string], b.chunked)

    def test_splitlines(self):
        for case in [
            [],
            [b"foo\nbar\n"],
            [b"bl\na", b"blie"],
            [b"bl\na", b"blie", b"bloe\n"],
            [b"", b"bl\na", b"blie", b"bloe\n"],
            [b"", b"", b"", b"bla\n"],
            [b"", b"", b"", b"bla\n", b""],
            [b"bl", b"", b"a\naaa"],
            [b"a\naaa", b"a"],
        ]:
            b = Blob()
            b.chunked = case
            self.assertEqual(b.data.splitlines(True), b.splitlines())

    def test_set_chunks(self):
        b = Blob()
        b.chunked = [b"te", b"st", b" 5\n"]
        self.assertEqual(b"test 5\n", b.data)
        b.chunked = [b"te", b"st", b" 6\n"]
        self.assertEqual(b"test 6\n", b.as_raw_string())
        self.assertEqual(b"test 6\n", bytes(b))

    def test_parse_legacy_blob(self):
        string = b"test 3\n"
        b = self.get_blob(c_sha)
        self.assertEqual(b.data, string)
        self.assertEqual(b.sha().hexdigest().encode("ascii"), c_sha)

    def test_eq(self):
        blob1 = self.get_blob(a_sha)
        blob2 = self.get_blob(a_sha)
        self.assertEqual(blob1, blob2)

    def test_read_tree_from_file(self):
        t = self.get_tree(tree_sha)
        self.assertEqual(t.items()[0], (b"a", 33188, a_sha))
        self.assertEqual(t.items()[1], (b"b", 33188, b_sha))

    def test_read_tree_from_file_parse_count(self):
        old_deserialize = Tree._deserialize

        def reset_deserialize():
            Tree._deserialize = old_deserialize

        self.addCleanup(reset_deserialize)
        self.deserialize_count = 0

        def counting_deserialize(*args, **kwargs):
            self.deserialize_count += 1
            return old_deserialize(*args, **kwargs)

        Tree._deserialize = counting_deserialize
        t = self.get_tree(tree_sha)
        self.assertEqual(t.items()[0], (b"a", 33188, a_sha))
        self.assertEqual(t.items()[1], (b"b", 33188, b_sha))
        self.assertEqual(self.deserialize_count, 1)

    def test_read_tag_from_file(self):
        t = self.get_tag(tag_sha)
        self.assertEqual(
            t.object, (Commit, b"51b668fd5bf7061b7d6fa525f88803e6cfadaa51")
        )
        self.assertEqual(t.name, b"signed")
        self.assertEqual(t.tagger, b"Ali Sabil <ali.sabil@gmail.com>")
        self.assertEqual(t.tag_time, 1231203091)
        self.assertEqual(t.message, b"This is a signed tag\n")
        self.assertEqual(
            t.signature,
            b"-----BEGIN PGP SIGNATURE-----\n"
            b"Version: GnuPG v1.4.9 (GNU/Linux)\n"
            b"\n"
            b"iEYEABECAAYFAkliqx8ACgkQqSMmLy9u/"
            b"kcx5ACfakZ9NnPl02tOyYP6pkBoEkU1\n"
            b"5EcAn0UFgokaSvS371Ym/4W9iJj6vh3h\n"
            b"=ql7y\n"
            b"-----END PGP SIGNATURE-----\n",
        )

    def test_read_commit_from_file(self):
        sha = b"60dacdc733de308bb77bb76ce0fb0f9b44c9769e"
        c = self.commit(sha)
        self.assertEqual(c.tree, tree_sha)
        self.assertEqual(c.parents, [b"0d89f20333fbb1d2f3a94da77f4981373d8f4310"])
        self.assertEqual(c.author, b"James Westby <jw+debian@jameswestby.net>")
        self.assertEqual(c.committer, b"James Westby <jw+debian@jameswestby.net>")
        self.assertEqual(c.commit_time, 1174759230)
        self.assertEqual(c.commit_timezone, 0)
        self.assertEqual(c.author_timezone, 0)
        self.assertEqual(c.message, b"Test commit\n")

    def test_read_commit_no_parents(self):
        sha = b"0d89f20333fbb1d2f3a94da77f4981373d8f4310"
        c = self.commit(sha)
        self.assertEqual(c.tree, b"90182552c4a85a45ec2a835cadc3451bebdfe870")
        self.assertEqual(c.parents, [])
        self.assertEqual(c.author, b"James Westby <jw+debian@jameswestby.net>")
        self.assertEqual(c.committer, b"James Westby <jw+debian@jameswestby.net>")
        self.assertEqual(c.commit_time, 1174758034)
        self.assertEqual(c.commit_timezone, 0)
        self.assertEqual(c.author_timezone, 0)
        self.assertEqual(c.message, b"Test commit\n")

    def test_read_commit_two_parents(self):
        sha = b"5dac377bdded4c9aeb8dff595f0faeebcc8498cc"
        c = self.commit(sha)
        self.assertEqual(c.tree, b"d80c186a03f423a81b39df39dc87fd269736ca86")
        self.assertEqual(
            c.parents,
            [
                b"ab64bbdcc51b170d21588e5c5d391ee5c0c96dfd",
                b"4cffe90e0a41ad3f5190079d7c8f036bde29cbe6",
            ],
        )
        self.assertEqual(c.author, b"James Westby <jw+debian@jameswestby.net>")
        self.assertEqual(c.committer, b"James Westby <jw+debian@jameswestby.net>")
        self.assertEqual(c.commit_time, 1174773719)
        self.assertEqual(c.commit_timezone, 0)
        self.assertEqual(c.author_timezone, 0)
        self.assertEqual(c.message, b"Merge ../b\n")

    def test_stub_sha(self):
        sha = b"5" * 40
        c = make_commit(id=sha, message=b"foo")
        self.assertIsInstance(c, Commit)
        self.assertEqual(sha, c.id)
        self.assertNotEqual(sha, c.sha())


class ShaFileCheckTests(TestCase):
    def assertCheckFails(self, cls, data):
        obj = cls()

        def do_check():
            obj.set_raw_string(data)
            obj.check()

        self.assertRaises(ObjectFormatException, do_check)

    def assertCheckSucceeds(self, cls, data):
        obj = cls()
        obj.set_raw_string(data)
        self.assertEqual(None, obj.check())


small_buffer_zlib_object = (
    b"\x48\x89\x15\xcc\x31\x0e\xc2\x30\x0c\x40\x51\xe6"
    b"\x9c\xc2\x3b\xaa\x64\x37\xc4\xc1\x12\x42\x5c\xc5"
    b"\x49\xac\x52\xd4\x92\xaa\x78\xe1\xf6\x94\xed\xeb"
    b"\x0d\xdf\x75\x02\xa2\x7c\xea\xe5\x65\xd5\x81\x8b"
    b"\x9a\x61\xba\xa0\xa9\x08\x36\xc9\x4c\x1a\xad\x88"
    b"\x16\xba\x46\xc4\xa8\x99\x6a\x64\xe1\xe0\xdf\xcd"
    b"\xa0\xf6\x75\x9d\x3d\xf8\xf1\xd0\x77\xdb\xfb\xdc"
    b"\x86\xa3\x87\xf1\x2f\x93\xed\x00\xb7\xc7\xd2\xab"
    b"\x2e\xcf\xfe\xf1\x3b\x50\xa4\x91\x53\x12\x24\x38"
    b"\x23\x21\x86\xf0\x03\x2f\x91\x24\x52"
)


class ShaFileTests(TestCase):
    def test_deflated_smaller_window_buffer(self):
        # zlib on some systems uses smaller buffers,
        # resulting in a different header.
        # See https://github.com/libgit2/libgit2/pull/464
        sf = ShaFile.from_file(BytesIO(small_buffer_zlib_object))
        self.assertEqual(sf.type_name, b"tag")
        self.assertEqual(sf.tagger, b" <@localhost>")


class CommitSerializationTests(TestCase):
    def make_commit(self, **kwargs):
        attrs = {
            "tree": b"d80c186a03f423a81b39df39dc87fd269736ca86",
            "parents": [
                b"ab64bbdcc51b170d21588e5c5d391ee5c0c96dfd",
                b"4cffe90e0a41ad3f5190079d7c8f036bde29cbe6",
            ],
            "author": b"James Westby <jw+debian@jameswestby.net>",
            "committer": b"James Westby <jw+debian@jameswestby.net>",
            "commit_time": 1174773719,
            "author_time": 1174773719,
            "commit_timezone": 0,
            "author_timezone": 0,
            "message": b"Merge ../b\n",
        }
        attrs.update(kwargs)
        return make_commit(**attrs)

    def test_encoding(self):
        c = self.make_commit(encoding=b"iso8859-1")
        self.assertIn(b"encoding iso8859-1\n", c.as_raw_string())

    def test_short_timestamp(self):
        c = self.make_commit(commit_time=30)
        c1 = Commit()
        c1.set_raw_string(c.as_raw_string())
        self.assertEqual(30, c1.commit_time)

    def test_full_tree(self):
        c = self.make_commit(commit_time=30)
        t = Tree()
        t.add(b"data-x", 0o644, Blob().id)
        c.tree = t
        c1 = Commit()
        c1.set_raw_string(c.as_raw_string())
        self.assertEqual(t.id, c1.tree)
        self.assertEqual(c.as_raw_string(), c1.as_raw_string())

    def test_raw_length(self):
        c = self.make_commit()
        self.assertEqual(len(c.as_raw_string()), c.raw_length())

    def test_simple(self):
        c = self.make_commit()
        self.assertEqual(c.id, b"5dac377bdded4c9aeb8dff595f0faeebcc8498cc")
        self.assertEqual(
            b"tree d80c186a03f423a81b39df39dc87fd269736ca86\n"
            b"parent ab64bbdcc51b170d21588e5c5d391ee5c0c96dfd\n"
            b"parent 4cffe90e0a41ad3f5190079d7c8f036bde29cbe6\n"
            b"author James Westby <jw+debian@jameswestby.net> "
            b"1174773719 +0000\n"
            b"committer James Westby <jw+debian@jameswestby.net> "
            b"1174773719 +0000\n"
            b"\n"
            b"Merge ../b\n",
            c.as_raw_string(),
        )

    def test_timezone(self):
        c = self.make_commit(commit_timezone=(5 * 60))
        self.assertIn(b" +0005\n", c.as_raw_string())

    def test_neg_timezone(self):
        c = self.make_commit(commit_timezone=(-1 * 3600))
        self.assertIn(b" -0100\n", c.as_raw_string())

    def test_deserialize(self):
        c = self.make_commit()
        d = Commit()
        d._deserialize(c.as_raw_chunks())
        self.assertEqual(c, d)

    def test_serialize_gpgsig(self):
        commit = self.make_commit(
            gpgsig=b"""-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1
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=X6RT
-----END PGP SIGNATURE-----"""
        )
        self.maxDiff = None
        self.assertEqual(
            b"""\
tree d80c186a03f423a81b39df39dc87fd269736ca86
parent ab64bbdcc51b170d21588e5c5d391ee5c0c96dfd
parent 4cffe90e0a41ad3f5190079d7c8f036bde29cbe6
author James Westby <jw+debian@jameswestby.net> 1174773719 +0000
committer James Westby <jw+debian@jameswestby.net> 1174773719 +0000
gpgsig -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v1
 
 iQIcBAABCgAGBQJULCdfAAoJEACAbyvXKaRXuKwP/RyP9PA49uAvu8tQVCC/uBa8
 vi975+xvO14R8Pp8k2nps7lSxCdtCd+xVT1VRHs0wNhOZo2YCVoU1HATkPejqSeV
 NScTHcxnk4/+bxyfk14xvJkNp7FlQ3npmBkA+lbV0Ubr33rvtIE5jiJPyz+SgWAg
 xdBG2TojV0squj00GoH/euK6aX7GgZtwdtpTv44haCQdSuPGDcI4TORqR6YSqvy3
 GPE+3ZqXPFFb+KILtimkxitdwB7CpwmNse2vE3rONSwTvi8nq3ZoQYNY73CQGkUy
 qoFU0pDtw87U3niFin1ZccDgH0bB6624sLViqrjcbYJeg815Htsu4rmzVaZADEVC
 XhIO4MThebusdk0AcNGjgpf3HRHk0DPMDDlIjm+Oao0cqovvF6VyYmcb0C+RmhJj
 dodLXMNmbqErwTk3zEkW0yZvNIYXH7m9SokPCZa4eeIM7be62X6h1mbt0/IU6Th+
 v18fS0iTMP/Viug5und+05C/v04kgDo0CPphAbXwWMnkE4B6Tl9sdyUYXtvQsL7x
 0+WP1gL27ANqNZiI07Kz/BhbBAQI/+2TFT7oGr0AnFPQ5jHp+3GpUf6OKuT1wT3H
 ND189UFuRuubxb42vZhpcXRbqJVWnbECTKVUPsGZqat3enQUB63uM4i6/RdONDZA
 fDeF1m4qYs+cUXKNUZ03
 =X6RT
 -----END PGP SIGNATURE-----

Merge ../b
""",
            commit.as_raw_string(),
        )

    def test_serialize_mergetag(self):
        tag = make_object(
            Tag,
            object=(Commit, b"a38d6181ff27824c79fc7df825164a212eff6a3f"),
            object_type_name=b"commit",
            name=b"v2.6.22-rc7",
            tag_time=1183319674,
            tag_timezone=0,
            tagger=b"Linus Torvalds <torvalds@woody.linux-foundation.org>",
            message=default_message,
        )
        commit = self.make_commit(mergetag=[tag])

        self.assertEqual(
            b"""tree d80c186a03f423a81b39df39dc87fd269736ca86
parent ab64bbdcc51b170d21588e5c5d391ee5c0c96dfd
parent 4cffe90e0a41ad3f5190079d7c8f036bde29cbe6
author James Westby <jw+debian@jameswestby.net> 1174773719 +0000
committer James Westby <jw+debian@jameswestby.net> 1174773719 +0000
mergetag object a38d6181ff27824c79fc7df825164a212eff6a3f
 type commit
 tag v2.6.22-rc7
 tagger Linus Torvalds <torvalds@woody.linux-foundation.org> 1183319674 +0000
 
 Linux 2.6.22-rc7
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v1.4.7 (GNU/Linux)
 
 iD8DBQBGiAaAF3YsRnbiHLsRAitMAKCiLboJkQECM/jpYsY3WPfvUgLXkACgg3ql
 OK2XeQOiEeXtT76rV4t2WR4=
 =ivrA
 -----END PGP SIGNATURE-----

Merge ../b
""",
            commit.as_raw_string(),
        )

    def test_serialize_mergetags(self):
        tag = make_object(
            Tag,
            object=(Commit, b"a38d6181ff27824c79fc7df825164a212eff6a3f"),
            object_type_name=b"commit",
            name=b"v2.6.22-rc7",
            tag_time=1183319674,
            tag_timezone=0,
            tagger=b"Linus Torvalds <torvalds@woody.linux-foundation.org>",
            message=default_message,
        )
        commit = self.make_commit(mergetag=[tag, tag])

        self.assertEqual(
            b"""tree d80c186a03f423a81b39df39dc87fd269736ca86
parent ab64bbdcc51b170d21588e5c5d391ee5c0c96dfd
parent 4cffe90e0a41ad3f5190079d7c8f036bde29cbe6
author James Westby <jw+debian@jameswestby.net> 1174773719 +0000
committer James Westby <jw+debian@jameswestby.net> 1174773719 +0000
mergetag object a38d6181ff27824c79fc7df825164a212eff6a3f
 type commit
 tag v2.6.22-rc7
 tagger Linus Torvalds <torvalds@woody.linux-foundation.org> 1183319674 +0000
 
 Linux 2.6.22-rc7
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v1.4.7 (GNU/Linux)
 
 iD8DBQBGiAaAF3YsRnbiHLsRAitMAKCiLboJkQECM/jpYsY3WPfvUgLXkACgg3ql
 OK2XeQOiEeXtT76rV4t2WR4=
 =ivrA
 -----END PGP SIGNATURE-----
mergetag object a38d6181ff27824c79fc7df825164a212eff6a3f
 type commit
 tag v2.6.22-rc7
 tagger Linus Torvalds <torvalds@woody.linux-foundation.org> 1183319674 +0000
 
 Linux 2.6.22-rc7
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v1.4.7 (GNU/Linux)
 
 iD8DBQBGiAaAF3YsRnbiHLsRAitMAKCiLboJkQECM/jpYsY3WPfvUgLXkACgg3ql
 OK2XeQOiEeXtT76rV4t2WR4=
 =ivrA
 -----END PGP SIGNATURE-----

Merge ../b
""",
            commit.as_raw_string(),
        )

    def test_deserialize_mergetag(self):
        tag = make_object(
            Tag,
            object=(Commit, b"a38d6181ff27824c79fc7df825164a212eff6a3f"),
            object_type_name=b"commit",
            name=b"v2.6.22-rc7",
            tag_time=1183319674,
            tag_timezone=0,
            tagger=b"Linus Torvalds <torvalds@woody.linux-foundation.org>",
            message=default_message,
        )
        commit = self.make_commit(mergetag=[tag])

        d = Commit()
        d._deserialize(commit.as_raw_chunks())
        self.assertEqual(commit, d)

    def test_deserialize_mergetags(self):
        tag = make_object(
            Tag,
            object=(Commit, b"a38d6181ff27824c79fc7df825164a212eff6a3f"),
            object_type_name=b"commit",
            name=b"v2.6.22-rc7",
            tag_time=1183319674,
            tag_timezone=0,
            tagger=b"Linus Torvalds <torvalds@woody.linux-foundation.org>",
            message=default_message,
        )
        commit = self.make_commit(mergetag=[tag, tag])

        d = Commit()
        d._deserialize(commit.as_raw_chunks())
        self.assertEqual(commit, d)


default_committer = b"James Westby <jw+debian@jameswestby.net> 1174773719 +0000"


class CommitParseTests(ShaFileCheckTests):
    def make_commit_lines(
        self,
        tree=b"d80c186a03f423a81b39df39dc87fd269736ca86",
        parents=[
            b"ab64bbdcc51b170d21588e5c5d391ee5c0c96dfd",
            b"4cffe90e0a41ad3f5190079d7c8f036bde29cbe6",
        ],
        author=default_committer,
        committer=default_committer,
        encoding=None,
        message=b"Merge ../b\n",
        extra=None,
    ):
        lines = []
        if tree is not None:
            lines.append(b"tree " + tree)
        if parents is not None:
            lines.extend(b"parent " + p for p in parents)
        if author is not None:
            lines.append(b"author " + author)
        if committer is not None:
            lines.append(b"committer " + committer)
        if encoding is not None:
            lines.append(b"encoding " + encoding)
        if extra is not None:
            for name, value in sorted(extra.items()):
                lines.append(name + b" " + value)
        lines.append(b"")
        if message is not None:
            lines.append(message)
        return lines

    def make_commit_text(self, **kwargs):
        return b"\n".join(self.make_commit_lines(**kwargs))

    def test_simple(self):
        c = Commit.from_string(self.make_commit_text())
        self.assertEqual(b"Merge ../b\n", c.message)
        self.assertEqual(b"James Westby <jw+debian@jameswestby.net>", c.author)
        self.assertEqual(b"James Westby <jw+debian@jameswestby.net>", c.committer)
        self.assertEqual(b"d80c186a03f423a81b39df39dc87fd269736ca86", c.tree)
        self.assertEqual(
            [
                b"ab64bbdcc51b170d21588e5c5d391ee5c0c96dfd",
                b"4cffe90e0a41ad3f5190079d7c8f036bde29cbe6",
            ],
            c.parents,
        )
        expected_time = datetime.datetime(2007, 3, 24, 22, 1, 59)
        self.assertEqual(
            expected_time, datetime.datetime.utcfromtimestamp(c.commit_time)
        )
        self.assertEqual(0, c.commit_timezone)
        self.assertEqual(
            expected_time, datetime.datetime.utcfromtimestamp(c.author_time)
        )
        self.assertEqual(0, c.author_timezone)
        self.assertEqual(None, c.encoding)

    def test_custom(self):
        c = Commit.from_string(self.make_commit_text(extra={b"extra-field": b"data"}))
        self.assertEqual([(b"extra-field", b"data")], c._extra)

    def test_encoding(self):
        c = Commit.from_string(self.make_commit_text(encoding=b"UTF-8"))
        self.assertEqual(b"UTF-8", c.encoding)

    def test_check(self):
        self.assertCheckSucceeds(Commit, self.make_commit_text())
        self.assertCheckSucceeds(Commit, self.make_commit_text(parents=None))
        self.assertCheckSucceeds(Commit, self.make_commit_text(encoding=b"UTF-8"))

        self.assertCheckFails(Commit, self.make_commit_text(tree=b"xxx"))
        self.assertCheckFails(Commit, self.make_commit_text(parents=[a_sha, b"xxx"]))
        bad_committer = b"some guy without an email address 1174773719 +0000"
        self.assertCheckFails(Commit, self.make_commit_text(committer=bad_committer))
        self.assertCheckFails(Commit, self.make_commit_text(author=bad_committer))
        self.assertCheckFails(Commit, self.make_commit_text(author=None))
        self.assertCheckFails(Commit, self.make_commit_text(committer=None))
        self.assertCheckFails(
            Commit, self.make_commit_text(author=None, committer=None)
        )

    def test_check_duplicates(self):
        # duplicate each of the header fields
        for i in range(5):
            lines = self.make_commit_lines(parents=[a_sha], encoding=b"UTF-8")
            lines.insert(i, lines[i])
            text = b"\n".join(lines)
            if lines[i].startswith(b"parent"):
                # duplicate parents are ok for now
                self.assertCheckSucceeds(Commit, text)
            else:
                self.assertCheckFails(Commit, text)

    def test_check_order(self):
        lines = self.make_commit_lines(parents=[a_sha], encoding=b"UTF-8")
        headers = lines[:5]
        rest = lines[5:]
        # of all possible permutations, ensure only the original succeeds
        for perm in permutations(headers):
            perm = list(perm)
            text = b"\n".join(perm + rest)
            if perm == headers:
                self.assertCheckSucceeds(Commit, text)
            else:
                self.assertCheckFails(Commit, text)

    def test_check_commit_with_unparseable_time(self):
        identity_with_wrong_time = (
            b"Igor Sysoev <igor@sysoev.ru> 18446743887488505614+42707004"
        )

        # Those fail at reading time
        self.assertCheckFails(
            Commit,
            self.make_commit_text(
                author=default_committer, committer=identity_with_wrong_time
            ),
        )
        self.assertCheckFails(
            Commit,
            self.make_commit_text(
                author=identity_with_wrong_time, committer=default_committer
            ),
        )

    def test_check_commit_with_overflow_date(self):
        """Date with overflow should raise an ObjectFormatException when checked."""
        identity_with_wrong_time = (
            b"Igor Sysoev <igor@sysoev.ru> 18446743887488505614 +42707004"
        )
        commit0 = Commit.from_string(
            self.make_commit_text(
                author=identity_with_wrong_time, committer=default_committer
            )
        )
        commit1 = Commit.from_string(
            self.make_commit_text(
                author=default_committer, committer=identity_with_wrong_time
            )
        )

        # Those fails when triggering the check() method
        for commit in [commit0, commit1]:
            with self.assertRaises(ObjectFormatException):
                commit.check()

    def test_mangled_author_line(self):
        """Mangled author line should successfully parse."""
        author_line = (
            b'Karl MacMillan <kmacmill@redhat.com> <"Karl MacMillan '
            b'<kmacmill@redhat.com>"> 1197475547 -0500'
        )
        expected_identity = (
            b'Karl MacMillan <kmacmill@redhat.com> <"Karl MacMillan '
            b'<kmacmill@redhat.com>">'
        )
        commit = Commit.from_string(self.make_commit_text(author=author_line))

        # The commit parses properly
        self.assertEqual(commit.author, expected_identity)

        # But the check fails because the author identity is bogus
        with self.assertRaises(ObjectFormatException):
            commit.check()

    def test_parse_gpgsig(self):
        c = Commit.from_string(
            b"""tree aaff74984cccd156a469afa7d9ab10e4777beb24
author Jelmer Vernooij <jelmer@samba.org> 1412179807 +0200
committer Jelmer Vernooij <jelmer@samba.org> 1412179807 +0200
gpgsig -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v1
 
 iQIcBAABCgAGBQJULCdfAAoJEACAbyvXKaRXuKwP/RyP9PA49uAvu8tQVCC/uBa8
 vi975+xvO14R8Pp8k2nps7lSxCdtCd+xVT1VRHs0wNhOZo2YCVoU1HATkPejqSeV
 NScTHcxnk4/+bxyfk14xvJkNp7FlQ3npmBkA+lbV0Ubr33rvtIE5jiJPyz+SgWAg
 xdBG2TojV0squj00GoH/euK6aX7GgZtwdtpTv44haCQdSuPGDcI4TORqR6YSqvy3
 GPE+3ZqXPFFb+KILtimkxitdwB7CpwmNse2vE3rONSwTvi8nq3ZoQYNY73CQGkUy
 qoFU0pDtw87U3niFin1ZccDgH0bB6624sLViqrjcbYJeg815Htsu4rmzVaZADEVC
 XhIO4MThebusdk0AcNGjgpf3HRHk0DPMDDlIjm+Oao0cqovvF6VyYmcb0C+RmhJj
 dodLXMNmbqErwTk3zEkW0yZvNIYXH7m9SokPCZa4eeIM7be62X6h1mbt0/IU6Th+
 v18fS0iTMP/Viug5und+05C/v04kgDo0CPphAbXwWMnkE4B6Tl9sdyUYXtvQsL7x
 0+WP1gL27ANqNZiI07Kz/BhbBAQI/+2TFT7oGr0AnFPQ5jHp+3GpUf6OKuT1wT3H
 ND189UFuRuubxb42vZhpcXRbqJVWnbECTKVUPsGZqat3enQUB63uM4i6/RdONDZA
 fDeF1m4qYs+cUXKNUZ03
 =X6RT
 -----END PGP SIGNATURE-----

foo
"""
        )
        self.assertEqual(b"foo\n", c.message)
        self.assertEqual([], c._extra)
        self.assertEqual(
            b"""-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1
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=X6RT
-----END PGP SIGNATURE-----""",
            c.gpgsig,
        )

    def test_parse_header_trailing_newline(self):
        c = Commit.from_string(
            b"""\
tree a7d6277f78d3ecd0230a1a5df6db00b1d9c521ac
parent c09b6dec7a73760fbdb478383a3c926b18db8bbe
author Neil Matatall <oreoshake@github.com> 1461964057 -1000
committer Neil Matatall <oreoshake@github.com> 1461964057 -1000
gpgsig -----BEGIN PGP SIGNATURE-----
 
 wsBcBAABCAAQBQJXI80ZCRA6pcNDcVZ70gAAarcIABs72xRX3FWeox349nh6ucJK
 CtwmBTusez2Zwmq895fQEbZK7jpaGO5TRO4OvjFxlRo0E08UFx3pxZHSpj6bsFeL
 hHsDXnCaotphLkbgKKRdGZo7tDqM84wuEDlh4MwNe7qlFC7bYLDyysc81ZX5lpMm
 2MFF1TvjLAzSvkT7H1LPkuR3hSvfCYhikbPOUNnKOo0sYjeJeAJ/JdAVQ4mdJIM0
 gl3REp9+A+qBEpNQI7z94Pg5Bc5xenwuDh3SJgHvJV6zBWupWcdB3fAkVd4TPnEZ
 nHxksHfeNln9RKseIDcy4b2ATjhDNIJZARHNfr6oy4u3XPW4svRqtBsLoMiIeuI=
 =ms6q
 -----END PGP SIGNATURE-----
 

3.3.0 version bump and docs
"""
        )
        self.assertEqual([], c._extra)
        self.assertEqual(
            b"""\
-----BEGIN PGP SIGNATURE-----

wsBcBAABCAAQBQJXI80ZCRA6pcNDcVZ70gAAarcIABs72xRX3FWeox349nh6ucJK
CtwmBTusez2Zwmq895fQEbZK7jpaGO5TRO4OvjFxlRo0E08UFx3pxZHSpj6bsFeL
hHsDXnCaotphLkbgKKRdGZo7tDqM84wuEDlh4MwNe7qlFC7bYLDyysc81ZX5lpMm
2MFF1TvjLAzSvkT7H1LPkuR3hSvfCYhikbPOUNnKOo0sYjeJeAJ/JdAVQ4mdJIM0
gl3REp9+A+qBEpNQI7z94Pg5Bc5xenwuDh3SJgHvJV6zBWupWcdB3fAkVd4TPnEZ
nHxksHfeNln9RKseIDcy4b2ATjhDNIJZARHNfr6oy4u3XPW4svRqtBsLoMiIeuI=
=ms6q
-----END PGP SIGNATURE-----\n""",
            c.gpgsig,
        )


_TREE_ITEMS = {
    b"a.c": (0o100755, b"d80c186a03f423a81b39df39dc87fd269736ca86"),
    b"a": (stat.S_IFDIR, b"d80c186a03f423a81b39df39dc87fd269736ca86"),
    b"a/c": (stat.S_IFDIR, b"d80c186a03f423a81b39df39dc87fd269736ca86"),
}

_SORTED_TREE_ITEMS = [
    TreeEntry(b"a.c", 0o100755, b"d80c186a03f423a81b39df39dc87fd269736ca86"),
    TreeEntry(b"a", stat.S_IFDIR, b"d80c186a03f423a81b39df39dc87fd269736ca86"),
    TreeEntry(b"a/c", stat.S_IFDIR, b"d80c186a03f423a81b39df39dc87fd269736ca86"),
]


class TreeTests(ShaFileCheckTests):
    def test_add(self):
        myhexsha = b"d80c186a03f423a81b39df39dc87fd269736ca86"
        x = Tree()
        x.add(b"myname", 0o100755, myhexsha)
        self.assertEqual(x[b"myname"], (0o100755, myhexsha))
        self.assertEqual(b"100755 myname\0" + hex_to_sha(myhexsha), x.as_raw_string())

    def test_simple(self):
        myhexsha = b"d80c186a03f423a81b39df39dc87fd269736ca86"
        x = Tree()
        x[b"myname"] = (0o100755, myhexsha)
        self.assertEqual(b"100755 myname\0" + hex_to_sha(myhexsha), x.as_raw_string())
        self.assertEqual(b"100755 myname\0" + hex_to_sha(myhexsha), bytes(x))

    def test_tree_update_id(self):
        x = Tree()
        x[b"a.c"] = (0o100755, b"d80c186a03f423a81b39df39dc87fd269736ca86")
        self.assertEqual(b"0c5c6bc2c081accfbc250331b19e43b904ab9cdd", x.id)
        x[b"a.b"] = (stat.S_IFDIR, b"d80c186a03f423a81b39df39dc87fd269736ca86")
        self.assertEqual(b"07bfcb5f3ada15bbebdfa3bbb8fd858a363925c8", x.id)

    def test_tree_iteritems_dir_sort(self):
        x = Tree()
        for name, item in _TREE_ITEMS.items():
            x[name] = item
        self.assertEqual(_SORTED_TREE_ITEMS, x.items())

    def test_tree_items_dir_sort(self):
        x = Tree()
        for name, item in _TREE_ITEMS.items():
            x[name] = item
        self.assertEqual(_SORTED_TREE_ITEMS, x.items())

    def _do_test_parse_tree(self, parse_tree):
        dir = os.path.join(os.path.dirname(__file__), "..", "testdata", "trees")
        o = Tree.from_path(hex_to_filename(dir, tree_sha))
        self.assertEqual(
            [(b"a", 0o100644, a_sha), (b"b", 0o100644, b_sha)],
            list(parse_tree(o.as_raw_string())),
        )
        # test a broken tree that has a leading 0 on the file mode
        broken_tree = b"0100644 foo\0" + hex_to_sha(a_sha)

        def eval_parse_tree(*args, **kwargs):
            return list(parse_tree(*args, **kwargs))

        self.assertEqual([(b"foo", 0o100644, a_sha)], eval_parse_tree(broken_tree))
        self.assertRaises(
            ObjectFormatException, eval_parse_tree, broken_tree, strict=True
        )

    test_parse_tree = functest_builder(_do_test_parse_tree, _parse_tree_py)
    test_parse_tree_extension = ext_functest_builder(_do_test_parse_tree, parse_tree)

    def _do_test_sorted_tree_items(self, sorted_tree_items):
        def do_sort(entries):
            return list(sorted_tree_items(entries, False))

        actual = do_sort(_TREE_ITEMS)
        self.assertEqual(_SORTED_TREE_ITEMS, actual)
        self.assertIsInstance(actual[0], TreeEntry)

        # C/Python implementations may differ in specific error types, but
        # should all error on invalid inputs.
        # For example, the C implementation has stricter type checks, so may
        # raise TypeError where the Python implementation raises
        # AttributeError.
        errors = (TypeError, ValueError, AttributeError)
        self.assertRaises(errors, do_sort, b"foo")
        self.assertRaises(errors, do_sort, {b"foo": (1, 2, 3)})

        myhexsha = b"d80c186a03f423a81b39df39dc87fd269736ca86"
        self.assertRaises(errors, do_sort, {b"foo": (b"xxx", myhexsha)})
        self.assertRaises(errors, do_sort, {b"foo": (0o100755, 12345)})

    test_sorted_tree_items = functest_builder(
        _do_test_sorted_tree_items, _sorted_tree_items_py
    )
    test_sorted_tree_items_extension = ext_functest_builder(
        _do_test_sorted_tree_items, sorted_tree_items
    )

    def _do_test_sorted_tree_items_name_order(self, sorted_tree_items):
        self.assertEqual(
            [
                TreeEntry(
                    b"a",
                    stat.S_IFDIR,
                    b"d80c186a03f423a81b39df39dc87fd269736ca86",
                ),
                TreeEntry(
                    b"a.c",
                    0o100755,
                    b"d80c186a03f423a81b39df39dc87fd269736ca86",
                ),
                TreeEntry(
                    b"a/c",
                    stat.S_IFDIR,
                    b"d80c186a03f423a81b39df39dc87fd269736ca86",
                ),
            ],
            list(sorted_tree_items(_TREE_ITEMS, True)),
        )

    test_sorted_tree_items_name_order = functest_builder(
        _do_test_sorted_tree_items_name_order, _sorted_tree_items_py
    )
    test_sorted_tree_items_name_order_extension = ext_functest_builder(
        _do_test_sorted_tree_items_name_order, sorted_tree_items
    )

    def test_check(self):
        t = Tree
        sha = hex_to_sha(a_sha)

        # filenames
        self.assertCheckSucceeds(t, b"100644 .a\0" + sha)
        self.assertCheckFails(t, b"100644 \0" + sha)
        self.assertCheckFails(t, b"100644 .\0" + sha)
        self.assertCheckFails(t, b"100644 a/a\0" + sha)
        self.assertCheckFails(t, b"100644 ..\0" + sha)
        self.assertCheckFails(t, b"100644 .git\0" + sha)

        # modes
        self.assertCheckSucceeds(t, b"100644 a\0" + sha)
        self.assertCheckSucceeds(t, b"100755 a\0" + sha)
        self.assertCheckSucceeds(t, b"160000 a\0" + sha)
        # TODO more whitelisted modes
        self.assertCheckFails(t, b"123456 a\0" + sha)
        self.assertCheckFails(t, b"123abc a\0" + sha)
        # should fail check, but parses ok
        self.assertCheckFails(t, b"0100644 foo\0" + sha)

        # shas
        self.assertCheckFails(t, b"100644 a\0" + (b"x" * 5))
        self.assertCheckFails(t, b"100644 a\0" + (b"x" * 18) + b"\0")
        self.assertCheckFails(t, b"100644 a\0" + (b"x" * 21) + b"\n100644 b\0" + sha)

        # ordering
        sha2 = hex_to_sha(b_sha)
        self.assertCheckSucceeds(t, b"100644 a\0" + sha + b"100644 b\0" + sha)
        self.assertCheckSucceeds(t, b"100644 a\0" + sha + b"100644 b\0" + sha2)
        self.assertCheckFails(t, b"100644 a\0" + sha + b"100755 a\0" + sha2)
        self.assertCheckFails(t, b"100644 b\0" + sha2 + b"100644 a\0" + sha)

    def test_iter(self):
        t = Tree()
        t[b"foo"] = (0o100644, a_sha)
        self.assertEqual({b"foo"}, set(t))


class TagSerializeTests(TestCase):
    def test_serialize_simple(self):
        x = make_object(
            Tag,
            tagger=b"Jelmer Vernooij <jelmer@samba.org>",
            name=b"0.1",
            message=b"Tag 0.1",
            object=(Blob, b"d80c186a03f423a81b39df39dc87fd269736ca86"),
            tag_time=423423423,
            tag_timezone=0,
        )
        self.assertEqual(
            (
                b"object d80c186a03f423a81b39df39dc87fd269736ca86\n"
                b"type blob\n"
                b"tag 0.1\n"
                b"tagger Jelmer Vernooij <jelmer@samba.org> "
                b"423423423 +0000\n"
                b"\n"
                b"Tag 0.1"
            ),
            x.as_raw_string(),
        )

    def test_serialize_none_message(self):
        x = make_object(
            Tag,
            tagger=b"Jelmer Vernooij <jelmer@samba.org>",
            name=b"0.1",
            message=None,
            object=(Blob, b"d80c186a03f423a81b39df39dc87fd269736ca86"),
            tag_time=423423423,
            tag_timezone=0,
        )
        self.assertEqual(
            (
                b"object d80c186a03f423a81b39df39dc87fd269736ca86\n"
                b"type blob\n"
                b"tag 0.1\n"
                b"tagger Jelmer Vernooij <jelmer@samba.org> "
                b"423423423 +0000\n"
            ),
            x.as_raw_string(),
        )


default_tagger = (
    b"Linus Torvalds <torvalds@woody.linux-foundation.org> " b"1183319674 -0700"
)
default_message = b"""Linux 2.6.22-rc7
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.7 (GNU/Linux)

iD8DBQBGiAaAF3YsRnbiHLsRAitMAKCiLboJkQECM/jpYsY3WPfvUgLXkACgg3ql
OK2XeQOiEeXtT76rV4t2WR4=
=ivrA
-----END PGP SIGNATURE-----
"""


class TagParseTests(ShaFileCheckTests):
    def make_tag_lines(
        self,
        object_sha=b"a38d6181ff27824c79fc7df825164a212eff6a3f",
        object_type_name=b"commit",
        name=b"v2.6.22-rc7",
        tagger=default_tagger,
        message=default_message,
    ):
        lines = []
        if object_sha is not None:
            lines.append(b"object " + object_sha)
        if object_type_name is not None:
            lines.append(b"type " + object_type_name)
        if name is not None:
            lines.append(b"tag " + name)
        if tagger is not None:
            lines.append(b"tagger " + tagger)
        if message is not None:
            lines.append(b"")
            lines.append(message)
        return lines

    def make_tag_text(self, **kwargs):
        return b"\n".join(self.make_tag_lines(**kwargs))

    def test_parse(self):
        x = Tag()
        x.set_raw_string(self.make_tag_text())
        self.assertEqual(
            b"Linus Torvalds <torvalds@woody.linux-foundation.org>", x.tagger
        )
        self.assertEqual(b"v2.6.22-rc7", x.name)
        object_type, object_sha = x.object
        self.assertEqual(b"a38d6181ff27824c79fc7df825164a212eff6a3f", object_sha)
        self.assertEqual(Commit, object_type)
        self.assertEqual(
            datetime.datetime.utcfromtimestamp(x.tag_time),
            datetime.datetime(2007, 7, 1, 19, 54, 34),
        )
        self.assertEqual(-25200, x.tag_timezone)

    def test_parse_no_tagger(self):
        x = Tag()
        x.set_raw_string(self.make_tag_text(tagger=None))
        self.assertEqual(None, x.tagger)
        self.assertEqual(b"v2.6.22-rc7", x.name)
        self.assertEqual(None, x.tag_time)

    def test_parse_no_message(self):
        x = Tag()
        x.set_raw_string(self.make_tag_text(message=None))
        self.assertEqual(None, x.message)
        self.assertEqual(
            b"Linus Torvalds <torvalds@woody.linux-foundation.org>", x.tagger
        )
        self.assertEqual(
            datetime.datetime.utcfromtimestamp(x.tag_time),
            datetime.datetime(2007, 7, 1, 19, 54, 34),
        )
        self.assertEqual(-25200, x.tag_timezone)
        self.assertEqual(b"v2.6.22-rc7", x.name)

    def test_check(self):
        self.assertCheckSucceeds(Tag, self.make_tag_text())
        self.assertCheckFails(Tag, self.make_tag_text(object_sha=None))
        self.assertCheckFails(Tag, self.make_tag_text(object_type_name=None))
        self.assertCheckFails(Tag, self.make_tag_text(name=None))
        self.assertCheckFails(Tag, self.make_tag_text(name=b""))
        self.assertCheckFails(Tag, self.make_tag_text(object_type_name=b"foobar"))
        self.assertCheckFails(
            Tag,
            self.make_tag_text(
                tagger=b"some guy without an email address 1183319674 -0700"
            ),
        )
        self.assertCheckFails(
            Tag,
            self.make_tag_text(
                tagger=(
                    b"Linus Torvalds <torvalds@woody.linux-foundation.org> "
                    b"Sun 7 Jul 2007 12:54:34 +0700"
                )
            ),
        )
        self.assertCheckFails(Tag, self.make_tag_text(object_sha=b"xxx"))

    def test_check_tag_with_unparseable_field(self):
        self.assertCheckFails(
            Tag,
            self.make_tag_text(
                tagger=(
                    b"Linus Torvalds <torvalds@woody.linux-foundation.org> "
                    b"423423+0000"
                )
            ),
        )

    def test_check_tag_with_overflow_time(self):
        """Date with overflow should raise an ObjectFormatException when checked."""
        author = f"Some Dude <some@dude.org> {MAX_TIME + 1} +0000"
        tag = Tag.from_string(self.make_tag_text(tagger=(author.encode())))
        with self.assertRaises(ObjectFormatException):
            tag.check()

    def test_check_duplicates(self):
        # duplicate each of the header fields
        for i in range(4):
            lines = self.make_tag_lines()
            lines.insert(i, lines[i])
            self.assertCheckFails(Tag, b"\n".join(lines))

    def test_check_order(self):
        lines = self.make_tag_lines()
        headers = lines[:4]
        rest = lines[4:]
        # of all possible permutations, ensure only the original succeeds
        for perm in permutations(headers):
            perm = list(perm)
            text = b"\n".join(perm + rest)
            if perm == headers:
                self.assertCheckSucceeds(Tag, text)
            else:
                self.assertCheckFails(Tag, text)

    def test_tree_copy_after_update(self):
        """Check Tree.id is correctly updated when the tree is copied after updated."""
        shas = []
        tree = Tree()
        shas.append(tree.id)
        tree.add(b"data", 0o644, Blob().id)
        copied = tree.copy()
        shas.append(tree.id)
        shas.append(copied.id)

        self.assertNotIn(shas[0], shas[1:])
        self.assertEqual(shas[1], shas[2])


class CheckTests(TestCase):
    def test_check_hexsha(self):
        check_hexsha(a_sha, "failed to check good sha")
        self.assertRaises(
            ObjectFormatException, check_hexsha, b"1" * 39, "sha too short"
        )
        self.assertRaises(
            ObjectFormatException, check_hexsha, b"1" * 41, "sha too long"
        )
        self.assertRaises(
            ObjectFormatException,
            check_hexsha,
            b"x" * 40,
            "invalid characters",
        )

    def test_check_identity(self):
        check_identity(
            b"Dave Borowitz <dborowitz@google.com>",
            "failed to check good identity",
        )
        check_identity(b" <dborowitz@google.com>", "failed to check good identity")
        self.assertRaises(
            ObjectFormatException,
            check_identity,
            b"<dborowitz@google.com>",
            "no space before email",
        )
        self.assertRaises(
            ObjectFormatException, check_identity, b"Dave Borowitz", "no email"
        )
        self.assertRaises(
            ObjectFormatException,
            check_identity,
            b"Dave Borowitz <dborowitz",
            "incomplete email",
        )
        self.assertRaises(
            ObjectFormatException,
            check_identity,
            b"dborowitz@google.com>",
            "incomplete email",
        )
        self.assertRaises(
            ObjectFormatException,
            check_identity,
            b"Dave Borowitz <<dborowitz@google.com>",
            "typo",
        )
        self.assertRaises(
            ObjectFormatException,
            check_identity,
            b"Dave Borowitz <dborowitz@google.com>>",
            "typo",
        )
        self.assertRaises(
            ObjectFormatException,
            check_identity,
            b"Dave Borowitz <dborowitz@google.com>xxx",
            "trailing characters",
        )
        self.assertRaises(
            ObjectFormatException,
            check_identity,
            b"Dave Borowitz <dborowitz@google.com>xxx",
            "trailing characters",
        )
        self.assertRaises(
            ObjectFormatException,
            check_identity,
            b"Dave<Borowitz <dborowitz@google.com>",
            "reserved byte in name",
        )
        self.assertRaises(
            ObjectFormatException,
            check_identity,
            b"Dave>Borowitz <dborowitz@google.com>",
            "reserved byte in name",
        )
        self.assertRaises(
            ObjectFormatException,
            check_identity,
            b"Dave\0Borowitz <dborowitz@google.com>",
            "null byte",
        )
        self.assertRaises(
            ObjectFormatException,
            check_identity,
            b"Dave\nBorowitz <dborowitz@google.com>",
            "newline byte",
        )


class TimezoneTests(TestCase):
    def test_parse_timezone_utc(self):
        self.assertEqual((0, False), parse_timezone(b"+0000"))

    def test_parse_timezone_utc_negative(self):
        self.assertEqual((0, True), parse_timezone(b"-0000"))

    def test_generate_timezone_utc(self):
        self.assertEqual(b"+0000", format_timezone(0))

    def test_generate_timezone_utc_negative(self):
        self.assertEqual(b"-0000", format_timezone(0, True))

    def test_parse_timezone_cet(self):
        self.assertEqual((60 * 60, False), parse_timezone(b"+0100"))

    def test_format_timezone_cet(self):
        self.assertEqual(b"+0100", format_timezone(60 * 60))

    def test_format_timezone_pdt(self):
        self.assertEqual(b"-0400", format_timezone(-4 * 60 * 60))

    def test_parse_timezone_pdt(self):
        self.assertEqual((-4 * 60 * 60, False), parse_timezone(b"-0400"))

    def test_format_timezone_pdt_half(self):
        self.assertEqual(b"-0440", format_timezone(int(((-4 * 60) - 40) * 60)))

    def test_format_timezone_double_negative(self):
        self.assertEqual(b"--700", format_timezone(int((7 * 60) * 60), True))

    def test_parse_timezone_pdt_half(self):
        self.assertEqual((((-4 * 60) - 40) * 60, False), parse_timezone(b"-0440"))

    def test_parse_timezone_double_negative(self):
        self.assertEqual((int((7 * 60) * 60), False), parse_timezone(b"+700"))
        self.assertEqual((int((7 * 60) * 60), True), parse_timezone(b"--700"))


class ShaFileCopyTests(TestCase):
    def assert_copy(self, orig):
        oclass = object_class(orig.type_num)

        copy = orig.copy()
        self.assertIsInstance(copy, oclass)
        self.assertEqual(copy, orig)
        self.assertIsNot(copy, orig)

    def test_commit_copy(self):
        attrs = {
            "tree": b"d80c186a03f423a81b39df39dc87fd269736ca86",
            "parents": [
                b"ab64bbdcc51b170d21588e5c5d391ee5c0c96dfd",
                b"4cffe90e0a41ad3f5190079d7c8f036bde29cbe6",
            ],
            "author": b"James Westby <jw+debian@jameswestby.net>",
            "committer": b"James Westby <jw+debian@jameswestby.net>",
            "commit_time": 1174773719,
            "author_time": 1174773719,
            "commit_timezone": 0,
            "author_timezone": 0,
            "message": b"Merge ../b\n",
        }
        commit = make_commit(**attrs)
        self.assert_copy(commit)

    def test_blob_copy(self):
        blob = make_object(Blob, data=b"i am a blob")
        self.assert_copy(blob)

    def test_tree_copy(self):
        blob = make_object(Blob, data=b"i am a blob")
        tree = Tree()
        tree[b"blob"] = (stat.S_IFREG, blob.id)
        self.assert_copy(tree)

    def test_tag_copy(self):
        tag = make_object(
            Tag,
            name=b"tag",
            message=b"",
            tagger=b"Tagger <test@example.com>",
            tag_time=12345,
            tag_timezone=0,
            object=(Commit, b"0" * 40),
        )
        self.assert_copy(tag)


class ShaFileSerializeTests(TestCase):
    """`ShaFile` objects only gets serialized once if they haven't changed."""

    @contextmanager
    def assert_serialization_on_change(
        self, obj, needs_serialization_after_change=True
    ):
        old_id = obj.id
        self.assertFalse(obj._needs_serialization)

        yield obj

        if needs_serialization_after_change:
            self.assertTrue(obj._needs_serialization)
        else:
            self.assertFalse(obj._needs_serialization)
        new_id = obj.id
        self.assertFalse(obj._needs_serialization)
        self.assertNotEqual(old_id, new_id)

    def test_commit_serialize(self):
        attrs = {
            "tree": b"d80c186a03f423a81b39df39dc87fd269736ca86",
            "parents": [
                b"ab64bbdcc51b170d21588e5c5d391ee5c0c96dfd",
                b"4cffe90e0a41ad3f5190079d7c8f036bde29cbe6",
            ],
            "author": b"James Westby <jw+debian@jameswestby.net>",
            "committer": b"James Westby <jw+debian@jameswestby.net>",
            "commit_time": 1174773719,
            "author_time": 1174773719,
            "commit_timezone": 0,
            "author_timezone": 0,
            "message": b"Merge ../b\n",
        }
        commit = make_commit(**attrs)

        with self.assert_serialization_on_change(commit):
            commit.parents = [b"ab64bbdcc51b170d21588e5c5d391ee5c0c96dfd"]

    def test_blob_serialize(self):
        blob = make_object(Blob, data=b"i am a blob")

        with self.assert_serialization_on_change(
            blob, needs_serialization_after_change=False
        ):
            blob.data = b"i am another blob"

    def test_tree_serialize(self):
        blob = make_object(Blob, data=b"i am a blob")
        tree = Tree()
        tree[b"blob"] = (stat.S_IFREG, blob.id)

        with self.assert_serialization_on_change(tree):
            tree[b"blob2"] = (stat.S_IFREG, blob.id)

    def test_tag_serialize(self):
        tag = make_object(
            Tag,
            name=b"tag",
            message=b"",
            tagger=b"Tagger <test@example.com>",
            tag_time=12345,
            tag_timezone=0,
            object=(Commit, b"0" * 40),
        )

        with self.assert_serialization_on_change(tag):
            tag.message = b"new message"

    def test_tag_serialize_time_error(self):
        with self.assertRaises(ObjectFormatException):
            tag = make_object(
                Tag,
                name=b"tag",
                message=b"some message",
                tagger=b"Tagger <test@example.com> 1174773719+0000",
                object=(Commit, b"0" * 40),
            )
            tag._deserialize(tag._serialize())


class PrettyFormatTreeEntryTests(TestCase):
    def test_format(self):
        self.assertEqual(
            "40000 tree 40820c38cfb182ce6c8b261555410d8382a5918b\tfoo\n",
            pretty_format_tree_entry(
                b"foo", 0o40000, b"40820c38cfb182ce6c8b261555410d8382a5918b"
            ),
        )