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#  or more contributor license agreements.  See the NOTICE file
#  distributed with this work for additional information
#  regarding copyright ownership.  The ASF licenses this file
#  to you under the Apache License, Version 2.0 (the
#  "License"); you may not use this file except in compliance
#  with the License.  You may obtain a copy of the License at
#
#   http://www.apache.org/licenses/LICENSE-2.0
#
#  Unless required by applicable law or agreed to in writing,
#  software distributed under the License is distributed on an
#  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
#  KIND, either express or implied.  See the License for the
#  specific language governing permissions and limitations
#  under the License.

from collections import deque
from fnmatch import fnmatch
import sys
try:
    import unittest2 as unittest
except ImportError:
    import unittest

from pkg_resources import resource_listdir, resource_isdir, resource_exists


class TestLoader(unittest.TestLoader):
    testLoaderAttribute = '__testloader__'
    testMethodPrefix = 'test'
    sortTestMethodsUsing = cmp
    suiteClass = unittest.TestSuite

    def discover_package(self, package_or_requirement, pattern='test*.py', ignore_subpkg_root=True):
        """Find and return all test modules from the specified package
        directory, recursing into subdirectories to find them. Only test files
        that match the pattern will be loaded. (Using shell style pattern
        matching.)

        All test modules must be importable from the top level of the project
        and registered with `pkg_resources` (e.g. via `setup.py develop`).

        If a target test module contains a '__testloader__' attribute then
        related object will override current loader for every individual 
        module across the hierarchy.
        """
        pending = deque([(package_or_requirement, self, True)])
        tests = []
        while pending:
            mdlnm, loader, isdir = pending.popleft()
            try:
                mdl = self._get_module_from_name(mdlnm)
            except (ImportError, ValueError):
                # Skip packages not having __init__.py
                continue
            loader = getattr(mdl, self.testLoaderAttribute, None) or loader
            if not (isdir and ignore_subpkg_root):
                if mdlnm != package_or_requirement and hasattr(mdl, 'test_suite'):
                    tests.append(mdl.test_suite())
                else:
                    tests.append(loader.loadTestsFromModule(mdl))
            if isdir and resource_exists(mdlnm, '__init__.py'):
                for fnm in resource_listdir(mdlnm, ''):
                    if resource_isdir(mdlnm, fnm):
                        pending.append( (mdlnm + '.' + fnm, loader, True) )
                    elif any(fnm.endswith(ext) for ext in ['.py', '.pyc']) \
                            and fnmatch(fnm, pattern) and fnm != '__init__.py':
                        submdlnm = mdlnm + '.' + fnm.rsplit('.', 1)[0]
                        pending.append( (submdlnm, loader, False) )
        return self.suiteClass(tests)

    def _get_module_from_name(self, name):
        __import__(name)
        return sys.modules[name]


def test_suite():
    return TestLoader().discover_package('tests', pattern='*.py')

if __name__ == '__main__':
    unittest.main(defaultTest='test_suite')