Initial checkin of gRPC to third_party/

third_party/grpc/src/python/grpcio/tests/_loader.py

Index: third_party/grpc/src/python/grpcio/tests/_loader.py
diff --git a/third_party/grpc/src/python/grpcio/tests/_loader.py b/third_party/grpc/src/python/grpcio/tests/_loader.py
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+++ b/third_party/grpc/src/python/grpcio/tests/_loader.py
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+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+import importlib
+import pkgutil
+import re
+import unittest
+
+import coverage
+
+TEST_MODULE_REGEX = r'^.*_test$'
+
+
+class Loader(object):
+  """Test loader for setuptools test suite support.
+
+  Attributes:
+    suite (unittest.TestSuite): All tests collected by the loader.
+    loader (unittest.TestLoader): Standard Python unittest loader to be ran per
+      module discovered.
+    module_matcher (re.RegexObject): A regular expression object to match
+      against module names and determine whether or not the discovered module
+      contributes to the test suite.
+  """
+
+  def __init__(self):
+    self.suite = unittest.TestSuite()
+    self.loader = unittest.TestLoader()
+    self.module_matcher = re.compile(TEST_MODULE_REGEX)
+
+  def loadTestsFromNames(self, names, module=None):
+    """Function mirroring TestLoader::loadTestsFromNames, as expected by
+    setuptools.setup argument `test_loader`."""
+    # ensure that we capture decorators and definitions (else our coverage
+    # measure unnecessarily suffers)
+    coverage_context = coverage.Coverage(data_suffix=True)
+    coverage_context.start()
+    modules = [importlib.import_module(name) for name in names]
+    for module in modules:
+      self.visit_module(module)
+    for module in modules:
+      try:
+        package_paths = module.__path__
+      except:
+        continue
+      self.walk_packages(package_paths)
+    coverage_context.stop()
+    coverage_context.save()
+    return self.suite
+
+  def walk_packages(self, package_paths):
+    """Walks over the packages, dispatching `visit_module` calls.
+
+    Args:
+      package_paths (list): A list of paths over which to walk through modules
+        along.
+    """
+    for importer, module_name, is_package in (
+        pkgutil.iter_modules(package_paths)):
+      module = importer.find_module(module_name).load_module(module_name)
+      self.visit_module(module)
+      if is_package:
+        self.walk_packages(module.__path__)
+
+  def visit_module(self, module):
+    """Visits the module, adding discovered tests to the test suite.
+
+    Args:
+      module (module): Module to match against self.module_matcher; if matched
+        it has its tests loaded via self.loader into self.suite.
+    """
+    if self.module_matcher.match(module.__name__):
+      module_suite = self.loader.loadTestsFromModule(module)
+      self.suite.addTest(module_suite)
+
+
+def iterate_suite_cases(suite):
+  """Generator over all unittest.TestCases in a unittest.TestSuite.
+
+  Args:
+    suite (unittest.TestSuite): Suite to iterate over in the generator.
+
+  Returns:
+    generator: A generator over all unittest.TestCases in `suite`.
+  """
+  for item in suite:
+    if isinstance(item, unittest.TestSuite):
+      for child_item in iterate_suite_cases(item):
+        yield child_item
+    elif isinstance(item, unittest.TestCase):
+      yield item
+    else:
+      raise ValueError('unexpected suite item of type {}'.format(type(item)))