tests/sitecustomize.py

tests: make chunk header of external diff glob-ed for portability

Before this patch, some tests using external "diff" command via
extdiff extension fail on Solaris, because system standard "diff" (=
/usr/bin/diff) on Solaris always formats chunk header in the style
below:

  @@ -X.x +Y.y @@

even though "diff" on Linux sometimes omits ".x" and/or ".y" in it.

This patch makes chunk header of external diff glob-ed for portability
of tests, and adds check-code.py rules to detect such diff output in
tests.

This patch also changes "hg diff" output in test-subrepo-git to
simplify detection rules, even though it is certainly portable because
these lines are generated by "git" command.

This patch is a part of making tests using external "diff" portable,
and tests below aren't yet portable even after this patch.

  test-largefiles-update.t
  test-subrepo-deep-nested-change.t

import os

if os.environ.get('COVERAGE_PROCESS_START'):
    try:
        import coverage
        import random

        # uuid is better, but not available in Python 2.4.
        covpath = os.path.join(os.environ['COVERAGE_DIR'],
                               'cov.%s' % random.randrange(0, 1000000000000))
        cov = coverage.coverage(data_file=covpath, auto_data=True)
        cov._warn_no_data = False
        cov._warn_unimported_source = False
        cov.start()
    except ImportError:
        pass