tests/test-mdiff.py

transaction: clarify the logic around pre-finalize/post-finalize

I am taking a bit more verbose route, but I find it easier to follow for people
who (re)discover the code.

(This is a gratuitous cleanup I did while looking at something else.)

Differential Revision: https://phab.mercurial-scm.org/D8176

from __future__ import absolute_import
from __future__ import print_function

import unittest

from mercurial import mdiff


class splitnewlinesTests(unittest.TestCase):
    def test_splitnewlines(self):
        cases = {
            b'a\nb\nc\n': [b'a\n', b'b\n', b'c\n'],
            b'a\nb\nc': [b'a\n', b'b\n', b'c'],
            b'a\nb\nc\n\n': [b'a\n', b'b\n', b'c\n', b'\n'],
            b'': [],
            b'abcabc': [b'abcabc'],
        }
        for inp, want in cases.items():
            self.assertEqual(mdiff.splitnewlines(inp), want)


if __name__ == '__main__':
    import silenttestrunner

    silenttestrunner.main(__name__)