view tests/test-simplemerge.py @ 39772:ae531f5e583c

testing: add interface unit tests for file storage

Our strategy for supporting alternate storage backends is to define
interfaces for everything then "code to the interface."

We already have interfaces for various primitives, including file
and manifest storage.

What we don't have is generic unit tests for those interfaces. Up
to this point we've been relying on high-level integration tests
(mainly in the form of existing .t tests) to test alternate storage
backends. And my experience with developing the "simple store" test
extension is that such testing is very tedious: it takes several
minutes to run all tests and when you find a failure, it is often
non-trivial to debug.

This commit starts to change that.

This commit introduces the mercurial.testing.storage module. It
contains testing code for storage. Currently, it defines some
unittest.TestCase classes for testing the file storage interfaces.
It also defines some factory functions that allow a caller to easily
spawn a custom TestCase "bound" to a specific file storage backend
implementation.

A new .py test has been added. It simply defines a callable to produce
filelog and transaction instances on demand and then "registers" the
various test classes so the filelog class can be tested with the
storage interface unit tests.

As part of writing the tests, I identified a couple of apparent
bugs in revlog.py and filelog.py! These are tracked with inline
TODO comments.

Writing the tests makes it more obvious where the storage interface
is lacking. For example, we raise either IndexError or
error.LookupError for missing revisions depending on whether we
use an integer revision or a node. Also, we raise error.RevlogError
in various places when we should be raising a storage-agnostic
error type.

The storage interfaces are currently far from perfect and there is much
work to be done to improve them. But at least with this commit we
finally have the start of unit tests that can be used to "qualify"
the behavior of a storage backend. And when implementing and debugging
new storage backends, we now have an obvious place to define new
tests and have obvious places to insert breakpoints to facilitate
debugging. This should be invaluable when implementing new storage
backends.

I added the mercurial.testing package because these interface
conformance tests are generic and need to be usable by all storage
backends. Having the code live in tests/ would make it difficult for
storage backends implemented in extensions to test their interface
conformance. First, it would require obtaining a copy of Mercurial's
storage test code in order to test. Second, it would make testing
against multiple Mercurial versions difficult, as you would need to
import N copies of the storage testing code in order to achieve test
coverage. By making the test code part of the Mercurial distribution
itself, extensions can `import mercurial.testing.*` to access and run
the test code. The test will run against whatever Mercurial version
is active.

FWIW I've always wanted to move parts of run-tests.py into the
mercurial.* package to make the testing story simpler (e.g. imagine an
`hg debugruntests` command that could invoke the test harness). While I
have no plans to do that in the near future, establishing the
mercurial.testing package does provide a natural home for that code
should someone do this in the future.

Differential Revision: https://phab.mercurial-scm.org/D4650

# Copyright (C) 2004, 2005 Canonical Ltd
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, see <http://www.gnu.org/licenses/>.

from __future__ import absolute_import

import unittest
from mercurial import (
    error,
    simplemerge,
    util,
)

from mercurial.utils import (
    stringutil,
)

TestCase = unittest.TestCase
# bzr compatible interface, for the tests
class Merge3(simplemerge.Merge3Text):
    """3-way merge of texts.

    Given BASE, OTHER, THIS, tries to produce a combined text
    incorporating the changes from both BASE->OTHER and BASE->THIS.
    All three will typically be sequences of lines."""
    def __init__(self, base, a, b):
        basetext = b'\n'.join([i.strip(b'\n') for i in base] + [b''])
        atext = b'\n'.join([i.strip(b'\n') for i in a] + [b''])
        btext = b'\n'.join([i.strip(b'\n') for i in b] + [b''])
        if (stringutil.binary(basetext) or stringutil.binary(atext)
            or stringutil.binary(btext)):
            raise error.Abort(b"don't know how to merge binary files")
        simplemerge.Merge3Text.__init__(self, basetext, atext, btext,
                                        base, a, b)

CantReprocessAndShowBase = simplemerge.CantReprocessAndShowBase

def split_lines(t):
    return util.stringio(t).readlines()

############################################################
# test case data from the gnu diffutils manual
# common base
TZU = split_lines(b"""     The Nameless is the origin of Heaven and Earth;
     The named is the mother of all things.

     Therefore let there always be non-being,
       so we may see their subtlety,
     And let there always be being,
       so we may see their outcome.
     The two are the same,
     But after they are produced,
       they have different names.
     They both may be called deep and profound.
     Deeper and more profound,
     The door of all subtleties!
""")

LAO = split_lines(b"""     The Way that can be told of is not the eternal Way;
     The name that can be named is not the eternal name.
     The Nameless is the origin of Heaven and Earth;
     The Named is the mother of all things.
     Therefore let there always be non-being,
       so we may see their subtlety,
     And let there always be being,
       so we may see their outcome.
     The two are the same,
     But after they are produced,
       they have different names.
""")


TAO = split_lines(b"""     The Way that can be told of is not the eternal Way;
     The name that can be named is not the eternal name.
     The Nameless is the origin of Heaven and Earth;
     The named is the mother of all things.

     Therefore let there always be non-being,
       so we may see their subtlety,
     And let there always be being,
       so we may see their result.
     The two are the same,
     But after they are produced,
       they have different names.

       -- The Way of Lao-Tzu, tr. Wing-tsit Chan

""")

MERGED_RESULT = split_lines(b"""\
     The Way that can be told of is not the eternal Way;
     The name that can be named is not the eternal name.
     The Nameless is the origin of Heaven and Earth;
     The Named is the mother of all things.
     Therefore let there always be non-being,
       so we may see their subtlety,
     And let there always be being,
       so we may see their result.
     The two are the same,
     But after they are produced,
       they have different names.\
\n<<<<<<< LAO\
\n=======

       -- The Way of Lao-Tzu, tr. Wing-tsit Chan
\
\n>>>>>>> TAO
""")

class TestMerge3(TestCase):
    def log(self, msg):
        pass

    def test_no_changes(self):
        """No conflicts because nothing changed"""
        m3 = Merge3([b'aaa', b'bbb'],
                    [b'aaa', b'bbb'],
                    [b'aaa', b'bbb'])

        self.assertEqual(m3.find_unconflicted(),
                         [(0, 2)])

        self.assertEqual(list(m3.find_sync_regions()),
                         [(0, 2,
                           0, 2,
                           0, 2),
                          (2, 2,  2, 2,  2, 2)])

        self.assertEqual(list(m3.merge_regions()),
                         [(b'unchanged', 0, 2)])

        self.assertEqual(list(m3.merge_groups()),
                         [(b'unchanged', [b'aaa', b'bbb'])])

    def test_front_insert(self):
        m3 = Merge3([b'zz'],
                    [b'aaa', b'bbb', b'zz'],
                    [b'zz'])

        # todo: should use a sentinel at end as from get_matching_blocks
        # to match without zz
        self.assertEqual(list(m3.find_sync_regions()),
                         [(0, 1,  2, 3,  0, 1),
                          (1, 1,  3, 3,  1, 1)])

        self.assertEqual(list(m3.merge_regions()),
                         [(b'a', 0, 2),
                          (b'unchanged', 0, 1)])

        self.assertEqual(list(m3.merge_groups()),
                         [(b'a', [b'aaa', b'bbb']),
                          (b'unchanged', [b'zz'])])

    def test_null_insert(self):
        m3 = Merge3([],
                    [b'aaa', b'bbb'],
                    [])
        # todo: should use a sentinel at end as from get_matching_blocks
        # to match without zz
        self.assertEqual(list(m3.find_sync_regions()),
                         [(0, 0,  2, 2,  0, 0)])

        self.assertEqual(list(m3.merge_regions()),
                         [(b'a', 0, 2)])

        self.assertEqual(list(m3.merge_lines()),
                         [b'aaa', b'bbb'])

    def test_no_conflicts(self):
        """No conflicts because only one side changed"""
        m3 = Merge3([b'aaa', b'bbb'],
                    [b'aaa', b'111', b'bbb'],
                    [b'aaa', b'bbb'])

        self.assertEqual(m3.find_unconflicted(),
                         [(0, 1), (1, 2)])

        self.assertEqual(list(m3.find_sync_regions()),
                         [(0, 1,  0, 1,  0, 1),
                          (1, 2,  2, 3,  1, 2),
                          (2, 2,  3, 3,  2, 2)])

        self.assertEqual(list(m3.merge_regions()),
                         [(b'unchanged', 0, 1),
                          (b'a', 1, 2),
                          (b'unchanged', 1, 2)])

    def test_append_a(self):
        m3 = Merge3([b'aaa\n', b'bbb\n'],
                    [b'aaa\n', b'bbb\n', b'222\n'],
                    [b'aaa\n', b'bbb\n'])

        self.assertEqual(b''.join(m3.merge_lines()),
                         b'aaa\nbbb\n222\n')

    def test_append_b(self):
        m3 = Merge3([b'aaa\n', b'bbb\n'],
                    [b'aaa\n', b'bbb\n'],
                    [b'aaa\n', b'bbb\n', b'222\n'])

        self.assertEqual(b''.join(m3.merge_lines()),
                         b'aaa\nbbb\n222\n')

    def test_append_agreement(self):
        m3 = Merge3([b'aaa\n', b'bbb\n'],
                    [b'aaa\n', b'bbb\n', b'222\n'],
                    [b'aaa\n', b'bbb\n', b'222\n'])

        self.assertEqual(b''.join(m3.merge_lines()),
                         b'aaa\nbbb\n222\n')

    def test_append_clash(self):
        m3 = Merge3([b'aaa\n', b'bbb\n'],
                    [b'aaa\n', b'bbb\n', b'222\n'],
                    [b'aaa\n', b'bbb\n', b'333\n'])

        ml = m3.merge_lines(name_a=b'a',
                            name_b=b'b',
                            start_marker=b'<<',
                            mid_marker=b'--',
                            end_marker=b'>>')
        self.assertEqual(b''.join(ml),
                         b'aaa\n'
                         b'bbb\n'
                         b'<< a\n'
                         b'222\n'
                         b'--\n'
                         b'333\n'
                         b'>> b\n'
                         )

    def test_insert_agreement(self):
        m3 = Merge3([b'aaa\n', b'bbb\n'],
                    [b'aaa\n', b'222\n', b'bbb\n'],
                    [b'aaa\n', b'222\n', b'bbb\n'])

        ml = m3.merge_lines(name_a=b'a',
                            name_b=b'b',
                            start_marker=b'<<',
                            mid_marker=b'--',
                            end_marker=b'>>')
        self.assertEqual(b''.join(ml), b'aaa\n222\nbbb\n')


    def test_insert_clash(self):
        """Both try to insert lines in the same place."""
        m3 = Merge3([b'aaa\n', b'bbb\n'],
                    [b'aaa\n', b'111\n', b'bbb\n'],
                    [b'aaa\n', b'222\n', b'bbb\n'])

        self.assertEqual(m3.find_unconflicted(),
                         [(0, 1), (1, 2)])

        self.assertEqual(list(m3.find_sync_regions()),
                         [(0, 1,  0, 1,  0, 1),
                          (1, 2,  2, 3,  2, 3),
                          (2, 2,  3, 3,  3, 3)])

        self.assertEqual(list(m3.merge_regions()),
                         [(b'unchanged', 0, 1),
                          (b'conflict', 1, 1,  1, 2,  1, 2),
                          (b'unchanged', 1, 2)])

        self.assertEqual(list(m3.merge_groups()),
                         [(b'unchanged', [b'aaa\n']),
                          (b'conflict', [], [b'111\n'], [b'222\n']),
                          (b'unchanged', [b'bbb\n']),
                          ])

        ml = m3.merge_lines(name_a=b'a',
                            name_b=b'b',
                            start_marker=b'<<',
                            mid_marker=b'--',
                            end_marker=b'>>')
        self.assertEqual(b''.join(ml),
b'''aaa
<< a
111
--
222
>> b
bbb
''')

    def test_replace_clash(self):
        """Both try to insert lines in the same place."""
        m3 = Merge3([b'aaa', b'000', b'bbb'],
                    [b'aaa', b'111', b'bbb'],
                    [b'aaa', b'222', b'bbb'])

        self.assertEqual(m3.find_unconflicted(),
                         [(0, 1), (2, 3)])

        self.assertEqual(list(m3.find_sync_regions()),
                         [(0, 1,  0, 1,  0, 1),
                           (2, 3,  2, 3,  2, 3),
                           (3, 3,  3, 3,  3, 3)])

    def test_replace_multi(self):
        """Replacement with regions of different size."""
        m3 = Merge3([b'aaa', b'000', b'000', b'bbb'],
                    [b'aaa', b'111', b'111', b'111', b'bbb'],
                    [b'aaa', b'222', b'222', b'222', b'222', b'bbb'])

        self.assertEqual(m3.find_unconflicted(),
                         [(0, 1), (3, 4)])


        self.assertEqual(list(m3.find_sync_regions()),
                         [(0, 1,  0, 1,  0, 1),
                          (3, 4,  4, 5,  5, 6),
                          (4, 4,  5, 5,  6, 6)])

    def test_merge_poem(self):
        """Test case from diff3 manual"""
        m3 = Merge3(TZU, LAO, TAO)
        ml = list(m3.merge_lines(b'LAO', b'TAO'))
        self.log(b'merge result:')
        self.log(b''.join(ml))
        self.assertEqual(ml, MERGED_RESULT)

    def test_binary(self):
        with self.assertRaises(error.Abort):
            Merge3([b'\x00'], [b'a'], [b'b'])

    def test_dos_text(self):
        base_text = b'a\r\n'
        this_text = b'b\r\n'
        other_text = b'c\r\n'
        m3 = Merge3(base_text.splitlines(True), other_text.splitlines(True),
                    this_text.splitlines(True))
        m_lines = m3.merge_lines(b'OTHER', b'THIS')
        self.assertEqual(b'<<<<<<< OTHER\r\nc\r\n=======\r\nb\r\n'
                         b'>>>>>>> THIS\r\n'.splitlines(True), list(m_lines))

    def test_mac_text(self):
        base_text = b'a\r'
        this_text = b'b\r'
        other_text = b'c\r'
        m3 = Merge3(base_text.splitlines(True), other_text.splitlines(True),
                    this_text.splitlines(True))
        m_lines = m3.merge_lines(b'OTHER', b'THIS')
        self.assertEqual(b'<<<<<<< OTHER\rc\r=======\rb\r'
                         b'>>>>>>> THIS\r'.splitlines(True), list(m_lines))

if __name__ == '__main__':
    # hide the timer
    import time
    orig = time.time
    try:
        time.time = lambda: 0
        unittest.main()
    finally:
        time.time = orig