tests/sitecustomize.py

fileset: add function to switch revision where fileset will be evaluated

If the subset isn't filtered yet, i.e. if fullmatchctx, the new subset is
recalculated from scratch. Otherwise, it is narrowed by the existing subset.

from __future__ import absolute_import
import os

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

        covpath = os.path.join(os.environ['COVERAGE_DIR'],
                               'cov.%s' % uuid.uuid1())
        cov = coverage.coverage(data_file=covpath, auto_data=True)
        cov._warn_no_data = False
        cov._warn_unimported_source = False
        cov.start()
    except ImportError:
        pass