tests/sitecustomize.py

demandimport: import sub-module relatively as expected (issue5208)

Before this patch, importing sub-module might (1) fail or (2) success
but import incorrect module, because demandimport tries to import
sub-module with level=-1 (on Python 2.x) or level=0 (on Python 3.x),
which is default value of "level" argument at construction of
"_demandmod" proxy object.

  (1) on Python 3.x, importing sub-module always fails to import
      existing sub-module

  (2) both on Python 2.x and 3.x, importing sub-module might import
      same name module on root level unintentionally

      On Python 2.x, existing sub-module is prior to this unexpected
      module. Therefore, this problem hasn't appeared.

To import sub-module relatively as expected, this patch specifies "1"
as import level explicitly at construction of "_demandmod" proxy
object for sub-module.

from __future__ import absolute_import
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