tests/test-bdiff.py
author Pierre-Yves David <pierre-yves.david@octobus.net>
Sat, 03 Jul 2021 03:48:35 +0200
changeset 47507 d4c795576aeb
parent 43076 2372284d9457
child 48966 6000f5b25c9b
permissions -rw-r--r--
dirstate-entry: turn dirstate tuple into a real object (like in C) With dirstate V2, the stored information and actual format will change. This mean we need to start an a better abstraction for a dirstate entry that a tuple directly accessed. By chance, the C code is already doing this and pretend to be a tuple. So it should be fairly easy. We start with turning the tuple into an object, we will slowly migrate the dirstate code to no longer use the tuple directly in later changesets. Differential Revision: https://phab.mercurial-scm.org/D10949

from __future__ import absolute_import, print_function
import collections
import struct
import unittest

from mercurial import mdiff


class diffreplace(collections.namedtuple('diffreplace', 'start end from_ to')):
    def __repr__(self):
        return 'diffreplace(%r, %r, %r, %r)' % self


class BdiffTests(unittest.TestCase):
    def assert_bdiff_applies(self, a, b):
        d = mdiff.textdiff(a, b)
        c = a
        if d:
            c = mdiff.patches(a, [d])
        self.assertEqual(
            c,
            b,
            (
                "bad diff+patch result from\n  %r to\n  "
                "%r: \nbdiff: %r\npatched: %r" % (a, b, d, c[:200])
            ),
        )

    def assert_bdiff(self, a, b):
        self.assert_bdiff_applies(a, b)
        self.assert_bdiff_applies(b, a)

    def test_bdiff_basic(self):
        cases = [
            (b"a\nc\n\n\n\n", b"a\nb\n\n\n"),
            (b"a\nb\nc\n", b"a\nc\n"),
            (b"", b""),
            (b"a\nb\nc", b"a\nb\nc"),
            (b"a\nb\nc\nd\n", b"a\nd\n"),
            (b"a\nb\nc\nd\n", b"a\nc\ne\n"),
            (b"a\nb\nc\n", b"a\nc\n"),
            (b"a\n", b"c\na\nb\n"),
            (b"a\n", b""),
            (b"a\n", b"b\nc\n"),
            (b"a\n", b"c\na\n"),
            (b"", b"adjfkjdjksdhfksj"),
            (b"", b"ab"),
            (b"", b"abc"),
            (b"a", b"a"),
            (b"ab", b"ab"),
            (b"abc", b"abc"),
            (b"a\n", b"a\n"),
            (b"a\nb", b"a\nb"),
        ]
        for a, b in cases:
            self.assert_bdiff(a, b)

    def showdiff(self, a, b):
        bin = mdiff.textdiff(a, b)
        pos = 0
        q = 0
        actions = []
        while pos < len(bin):
            p1, p2, l = struct.unpack(">lll", bin[pos : pos + 12])
            pos += 12
            if p1:
                actions.append(a[q:p1])
            actions.append(diffreplace(p1, p2, a[p1:p2], bin[pos : pos + l]))
            pos += l
            q = p2
        if q < len(a):
            actions.append(a[q:])
        return actions

    def test_issue1295(self):
        cases = [
            (
                b"x\n\nx\n\nx\n\nx\n\nz\n",
                b"x\n\nx\n\ny\n\nx\n\nx\n\nz\n",
                [
                    b'x\n\nx\n\n',
                    diffreplace(6, 6, b'', b'y\n\n'),
                    b'x\n\nx\n\nz\n',
                ],
            ),
            (
                b"x\n\nx\n\nx\n\nx\n\nz\n",
                b"x\n\nx\n\ny\n\nx\n\ny\n\nx\n\nz\n",
                [
                    b'x\n\nx\n\n',
                    diffreplace(6, 6, b'', b'y\n\n'),
                    b'x\n\n',
                    diffreplace(9, 9, b'', b'y\n\n'),
                    b'x\n\nz\n',
                ],
            ),
        ]
        for old, new, want in cases:
            self.assertEqual(self.showdiff(old, new), want)

    def test_issue1295_varies_on_pure(self):
        # we should pick up abbbc. rather than bc.de as the longest match
        got = self.showdiff(
            b"a\nb\nb\nb\nc\n.\nd\ne\n.\nf\n",
            b"a\nb\nb\na\nb\nb\nb\nc\n.\nb\nc\n.\nd\ne\nf\n",
        )
        want_c = [
            b'a\nb\nb\n',
            diffreplace(6, 6, b'', b'a\nb\nb\nb\nc\n.\n'),
            b'b\nc\n.\nd\ne\n',
            diffreplace(16, 18, b'.\n', b''),
            b'f\n',
        ]
        want_pure = [
            diffreplace(0, 0, b'', b'a\nb\nb\n'),
            b'a\nb\nb\nb\nc\n.\n',
            diffreplace(12, 12, b'', b'b\nc\n.\n'),
            b'd\ne\n',
            diffreplace(16, 18, b'.\n', b''),
            b'f\n',
        ]
        self.assertTrue(
            got in (want_c, want_pure),
            'got: %r, wanted either %r or %r' % (got, want_c, want_pure),
        )

    def test_fixws(self):
        cases = [
            (b" \ta\r b\t\n", b"ab\n", 1),
            (b" \ta\r b\t\n", b" a b\n", 0),
            (b"", b"", 1),
            (b"", b"", 0),
        ]
        for a, b, allws in cases:
            c = mdiff.fixws(a, allws)
            self.assertEqual(
                c, b, 'fixws(%r) want %r got %r (allws=%r)' % (a, b, c, allws)
            )

    def test_nice_diff_for_trivial_change(self):
        self.assertEqual(
            self.showdiff(
                b''.join(b'<%d\n-\n' % i for i in range(5)),
                b''.join(b'>%d\n-\n' % i for i in range(5)),
            ),
            [
                diffreplace(0, 3, b'<0\n', b'>0\n'),
                b'-\n',
                diffreplace(5, 8, b'<1\n', b'>1\n'),
                b'-\n',
                diffreplace(10, 13, b'<2\n', b'>2\n'),
                b'-\n',
                diffreplace(15, 18, b'<3\n', b'>3\n'),
                b'-\n',
                diffreplace(20, 23, b'<4\n', b'>4\n'),
                b'-\n',
            ],
        )

    def test_prefer_appending(self):
        # 1 line to 3 lines
        self.assertEqual(
            self.showdiff(b'a\n', b'a\n' * 3),
            [b'a\n', diffreplace(2, 2, b'', b'a\na\n')],
        )
        # 1 line to 5 lines
        self.assertEqual(
            self.showdiff(b'a\n', b'a\n' * 5),
            [b'a\n', diffreplace(2, 2, b'', b'a\na\na\na\n')],
        )

    def test_prefer_removing_trailing(self):
        # 3 lines to 1 line
        self.assertEqual(
            self.showdiff(b'a\n' * 3, b'a\n'),
            [b'a\n', diffreplace(2, 6, b'a\na\n', b'')],
        )
        # 5 lines to 1 line
        self.assertEqual(
            self.showdiff(b'a\n' * 5, b'a\n'),
            [b'a\n', diffreplace(2, 10, b'a\na\na\na\n', b'')],
        )


if __name__ == '__main__':
    import silenttestrunner

    silenttestrunner.main(__name__)