tests/test-mdiff.py

rust-performance: introduce FastHashMap type alias for HashMap

Rust's default hashing is slow, because it is meant for preventing collision
attacks.
For all of the current Rust code, we don't care about those attacks, because
if an person with bad intentions has write access to your repo, you have other
issues.

I've chosen to use the TwoXHash crate because it was made by a reputable member
of the Rust community and has very good benchmarks.

For now it does not seem to improve performance by much for the current code,
but it's something else to not worry about when benchmarking code: in a
previous experiment with copytracing in Rust, it accounted for more than 10%
of the time of the entire script.

Differential Revision: https://phab.mercurial-scm.org/D7116

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__)