testing_support/coverage_utils.py

# Copyright 2013 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

import distutils.version
import os
import sys
import textwrap
import unittest

ROOT_PATH = os.path.abspath(os.path.join(
    os.path.dirname(os.path.dirname(__file__))))


def native_error(msg, version):
  print textwrap.dedent("""\
  ERROR: Native python-coverage (version: %s) is required to be
  installed on your PYTHONPATH to run this test. Recommendation:
     sudo apt-get install pip
     sudo pip install --upgrade coverage
  %s""") % (version, msg)
  sys.exit(1)

def covered_main(includes, require_native=None, required_percentage=100.0):
  """Equivalent of unittest.main(), except that it gathers coverage data, and
  asserts if the test is not at 100% coverage.

  Args:
    includes (list(str) or str) - List of paths to include in coverage report.
      May also be a single path instead of a list.
    require_native (str) - If non-None, will require that
      at least |require_native| version of coverage is installed on the
      system with CTracer.
  """
  try:
    import coverage
    if require_native is not None:
      got_ver = coverage.__version__
      if not getattr(coverage.collector, 'CTracer', None):
        native_error((
            "Native python-coverage module required.\n"
            "Pure-python implementation (version: %s) found: %s"
          ) % (got_ver, coverage), require_native)
      if got_ver < distutils.version.LooseVersion(require_native):
        native_error("Wrong version (%s) found: %s" % (got_ver, coverage),
                     require_native)
  except ImportError:
    if require_native is None:
      sys.path.insert(0, os.path.join(ROOT_PATH, 'third_party'))
      import coverage
    else:
      print ("ERROR: python-coverage (%s) is required to be installed on your "
             "PYTHONPATH to run this test." % require_native)
      sys.exit(1)

  COVERAGE = coverage.coverage(include=includes)
  COVERAGE.start()

  retcode = 0
  try:
    unittest.main()
  except SystemExit as e:
    retcode = e.code or retcode

  COVERAGE.stop()
  if COVERAGE.report() < required_percentage:
    print 'FATAL: not at required %f%% coverage.' % required_percentage
    retcode = 2

  return retcode