tests/sitecustomize.py

pyoxidizer: force pip to not use pep517 in order to be able to install hg

Mercurial is not (yet) a pep517 package, but the presence of a pyproject.toml
file tells newer-ish versions of pip that it should be one.

This is related to 58fe6d127a01, and fixes pyoxidizer builds for the Heptapod
CI.

Differential Revision: https://phab.mercurial-scm.org/D11710

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