tests/test-parseindex

actually port simplemerge to hg

- use bdiff instead of patiencediff;  this is a larger change, since
  bdiff works on 2 multi-line strings, while patiencediff works on 2
  lists;

- rename the main class from Merge3 to Merge3Text and add a Merge3
  class that derives from Merge3Text.  This new Merge3 class has
  the same interface from the original class, so that the tests
  still work;

  - Merge3 uses util.binary to detect binary data and raises
    util.Abort instead of a specific exception;

- don't use the @decorator syntax, to keep python2.3 compatibility;

- the test uses unittest, which likes to print how long it took to
  run.  This obviously doesn't play too well with hg's test suite,
  so we override time.time to fool unittest;

- one test has a different (but still valid) output because of the
  different diff algorithm used;

- the TestCase class used by bzr has some extras to help debugging.
  test-merge3.py used 2 of them:

  - log method to log some data

  - assertEqualDiff method to ease viewing diffs of diffs

  We add a dummy log method and use regular assertEquals instead of
  assertEqualDiff.

- make simplemerge executable and add "#!/usr/bin/env python" header

#!/bin/sh
#
# revlog.parseindex must be able to parse the index file even if
# an index entry is split between two 64k blocks.  The ideal test
# would be to create an index file with inline data where
# 64k < size < 64k + 64 (64k is the size of the read buffer, 64 is
# the size of an index entry) and with an index entry starting right
# before the 64k block boundary, and try to read it.
#
# We approximate that by reducing the read buffer to 1 byte.
#

hg init a
cd a
echo abc > foo
hg add foo
hg commit -m 'add foo' -d '1000000 0'

echo >> foo
hg commit -m 'change foo' -d '1000001 0'
hg log -r 0:

cat >> test.py << EOF
from mercurial import changelog, util
from mercurial.node import *

class singlebyteread(object):
    def __init__(self, real):
        self.real = real

    def read(self, size=-1):
        if size == 65536:
            size = 1
        return self.real.read(size)

    def __getattr__(self, key):
        return getattr(self.real, key)

def opener(*args):
    o = util.opener(*args)
    def wrapper(*a):
        f = o(*a)
        return singlebyteread(f)
    return wrapper

cl = changelog.changelog(opener('.hg/store'))
print cl.count(), 'revisions:'
for r in xrange(cl.count()):
    print short(cl.node(r))
EOF

python test.py