def build_test(label):
    parts = label.split('.')
    if len(parts) < 2 or len(parts) > 3:
        raise ValueError("Test label '%s' should be of the form app.TestCase "
                         "or app.TestCase.test_method" % label)

    #
    # First, look for TestCase instances with a name that matches
    #
    app_module = get_app(parts[0])
    test_module = get_tests(app_module)
    TestClass = getattr(app_module, parts[1], None)

    # Couldn't find the test class in models.py; look in tests.py
    if TestClass is None:
        if test_module:
            TestClass = getattr(test_module, parts[1], None)

    try:
        if issubclass(TestClass, (unittest.TestCase, real_unittest.TestCase)):
            if len(parts) == 2: # label is app.TestClass
                try:
                    return unittest.TestLoader().loadTestsFromTestCase(
                        TestClass)
                except TypeError:
                    raise ValueError(
                        "Test label '%s' does not refer to a test class"
                        % label)
            else: # label is app.TestClass.test_method
                return TestClass(parts[2])
    except TypeError:
        # TestClass isn't a TestClass - it must be a method or normal class
        pass

    #
    # If there isn't a TestCase, look for a doctest that matches
    #
    tests = []
    for module in app_module, test_module:
        try:
            doctests = make_doctest(module)
            # Now iterate over the suite, looking for doctests whose name
            # matches the pattern that was given
            for test in doctests:
                if test._dt_test.name in (
                        '%s.%s' % (module.__name__, '.'.join(parts[1:])),
                        '%s.__test__.%s' % (
                            module.__name__, '.'.join(parts[1:]))):
                    tests.append(test)
        except ValueError:
            # No doctests found.
            pass

    # If no tests were found, then we were given a bad test label.
    if not tests:
        raise ValueError("Test label '%s' does not refer to a test" % label)

    # Construct a suite out of the tests that matched.
    return unittest.TestSuite(tests)
Return a substring of a larger string
dataset/ETHPy150Open cloudera/hue/desktop/core/ext-py/Django-1.6.10/django/test/simple.py/build_test--crossover with--dataset/ETHPy150Open jookies/jasmin/jasmin/vendor/txredisapi.py/RedisProtocol.substr