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import re
import unittest

from webkitpy.common.checkout.diff_parser import DiffParser
from webkitpy.common.checkout.diff_test_data import DIFF_TEST_DATA


class DiffParserTest(unittest.TestCase):

    def test_diff_parser(self, parser=None):
        if not parser:
            parser = DiffParser(DIFF_TEST_DATA.splitlines())
        self.assertEqual(3, len(parser.files))

        self.assertIn('WebCore/style/StyleFlexibleBoxData.h', parser.files)
        diff = parser.files['WebCore/style/StyleFlexibleBoxData.h']
        self.assertEqual(7, len(diff.lines))

        # The first two unchanged lines.
        self.assertEqual((47, 47), diff.lines[0][0:2])
        self.assertEqual('', diff.lines[0][2])
        self.assertEqual((48, 48), diff.lines[1][0:2])
        self.assertEqual('    unsigned align : 3; // EBoxAlignment', diff.lines[1][2])

        # The deleted line.
        self.assertEqual((50, 0), diff.lines[3][0:2])
        self.assertEqual('    unsigned orient: 1; // EBoxOrient', diff.lines[3][2])

        # The first file looks OK. Let's check the next, more complicated file.
        self.assertIn('WebCore/style/StyleRareInheritedData.cpp', parser.files)
        diff = parser.files['WebCore/style/StyleRareInheritedData.cpp']

        # There are 3 chunks.
        self.assertEqual(7 + 7 + 9, len(diff.lines))

        # Around an added line.
        self.assertEqual((60, 61), diff.lines[9][0:2])
        self.assertEqual((0, 62), diff.lines[10][0:2])
        self.assertEqual((61, 63), diff.lines[11][0:2])

        # Look through the last chunk, which contains both adds and deletes.
        self.assertEqual((81, 83), diff.lines[14][0:2])
        self.assertEqual((82, 84), diff.lines[15][0:2])
        self.assertEqual((83, 85), diff.lines[16][0:2])
        self.assertEqual((84, 0), diff.lines[17][0:2])
        self.assertEqual((0, 86), diff.lines[18][0:2])
        self.assertEqual((0, 87), diff.lines[19][0:2])
        self.assertEqual((85, 88), diff.lines[20][0:2])
        self.assertEqual((86, 89), diff.lines[21][0:2])
        self.assertEqual((87, 90), diff.lines[22][0:2])

        # Check if a newly added file is correctly handled.
        diff = parser.files['LayoutTests/platform/mac/fast/flexbox/box-orient-button-expected.checksum']
        self.assertEqual(1, len(diff.lines))
        self.assertEqual((0, 1), diff.lines[0][0:2])

    def test_diff_parser_with_different_mnemonic_prefixes(self):
        # This repeats test_diff_parser but with different versions
        # of DIFF_TEST_DATA that use other prefixes instead of a/b.
        prefixes = (
            ('i', 'w'),  # git-diff (compares the (i)ndex and the (w)ork tree)
            ('c', 'w'),  # git-diff HEAD (compares a (c)ommit and the (w)ork tree)
            ('c', 'i'),  # git diff --cached (compares a (c)ommit and the (i)ndex)
            ('o', 'w'),  # git-diff HEAD:file1 file2 (compares an (o)bject and a (w)ork tree entity)
            ('1', '2'),  # git diff --no-index a b (compares two non-git things (1) and (2))
        )
        for a_replacement, b_replacement in prefixes:
            patch = self._patch(a_replacement, b_replacement)
            self.test_diff_parser(DiffParser(patch.splitlines()))

    @staticmethod
    def _patch(a_replacement='a', b_replacement='b'):
        """Returns a version of the example patch with mnemonic prefixes a/b changed."""
        patch = re.sub(r' a/', ' %s/' % a_replacement, DIFF_TEST_DATA)
        return re.sub(r' b/', ' %s/' % b_replacement, patch)