import os.path from os.path import abspath import re import sys import types import pickle from test import support from test.support import import_helper import test.test_importlib.util import unittest import unittest.mock import unittest.test class TestableTestProgram(unittest.TestProgram): module = None exit = True defaultTest = failfast = catchbreak = buffer = None verbosity = 1 progName = '' testRunner = testLoader = None def __init__(self): pass class TestDiscovery(unittest.TestCase): # Heavily mocked tests so I can avoid hitting the filesystem def test_get_name_from_path(self): loader = unittest.TestLoader() loader._top_level_dir = '/foo' name = loader._get_name_from_path('/foo/bar/baz.py') self.assertEqual(name, 'bar.baz') if not __debug__: # asserts are off return with self.assertRaises(AssertionError): loader._get_name_from_path('/bar/baz.py') def test_find_tests(self): loader = unittest.TestLoader() original_listdir = os.listdir def restore_listdir(): os.listdir = original_listdir original_isfile = os.path.isfile def restore_isfile(): os.path.isfile = original_isfile original_isdir = os.path.isdir def restore_isdir(): os.path.isdir = original_isdir path_lists = [['test2.py', 'test1.py', 'not_a_test.py', 'test_dir', 'test.foo', 'test-not-a-module.py', 'another_dir'], ['test4.py', 'test3.py', ]] os.listdir = lambda path: path_lists.pop(0) self.addCleanup(restore_listdir) def isdir(path): return path.endswith('dir') os.path.isdir = isdir self.addCleanup(restore_isdir) def isfile(path): # another_dir is not a package and so shouldn't be recursed into return not path.endswith('dir') and not 'another_dir' in path os.path.isfile = isfile self.addCleanup(restore_isfile) loader._get_module_from_name = lambda path: path + ' module' orig_load_tests = loader.loadTestsFromModule def loadTestsFromModule(module, pattern=None): # This is where load_tests is called. base = orig_load_tests(module, pattern=pattern) return base + [module + ' tests'] loader.loadTestsFromModule = loadTestsFromModule loader.suiteClass = lambda thing: thing top_level = os.path.abspath('/foo') loader._top_level_dir = top_level suite = list(loader._find_tests(top_level, 'test*.py')) # The test suites found should be sorted alphabetically for reliable # execution order. expected = [[name + ' module tests'] for name in ('test1', 'test2', 'test_dir')] expected.extend([[('test_dir.%s' % name) + ' module tests'] for name in ('test3', 'test4')]) self.assertEqual(suite, expected) def test_find_tests_socket(self): # A socket is neither a directory nor a regular file. # https://bugs.python.org/issue25320 loader = unittest.TestLoader() original_listdir = os.listdir def restore_listdir(): os.listdir = original_listdir original_isfile = os.path.isfile def restore_isfile(): os.path.isfile = original_isfile original_isdir = os.path.isdir def restore_isdir(): os.path.isdir = original_isdir path_lists = [['socket']] os.listdir = lambda path: path_lists.pop(0) self.addCleanup(restore_listdir) os.path.isdir = lambda path: False self.addCleanup(restore_isdir) os.path.isfile = lambda path: False self.addCleanup(restore_isfile) loader._get_module_from_name = lambda path: path + ' module' orig_load_tests = loader.loadTestsFromModule def loadTestsFromModule(module, pattern=None): # This is where load_tests is called. base = orig_load_tests(module, pattern=pattern) return base + [module + ' tests'] loader.loadTestsFromModule = loadTestsFromModule loader.suiteClass = lambda thing: thing top_level = os.path.abspath('/foo') loader._top_level_dir = top_level suite = list(loader._find_tests(top_level, 'test*.py')) self.assertEqual(suite, []) def test_find_tests_with_package(self): loader = unittest.TestLoader() original_listdir = os.listdir def restore_listdir(): os.listdir = original_listdir original_isfile = os.path.isfile def restore_isfile(): os.path.isfile = original_isfile original_isdir = os.path.isdir def restore_isdir(): os.path.isdir = original_isdir directories = ['a_directory', 'test_directory', 'test_directory2'] path_lists = [directories, [], [], []] os.listdir = lambda path: path_lists.pop(0) self.addCleanup(restore_listdir) os.path.isdir = lambda path: True self.addCleanup(restore_isdir) os.path.isfile = lambda path: os.path.basename(path) not in directories self.addCleanup(restore_isfile) class Module(object): paths = [] load_tests_args = [] def __init__(self, path): self.path = path self.paths.append(path) if os.path.basename(path) == 'test_directory': def load_tests(loader, tests, pattern): self.load_tests_args.append((loader, tests, pattern)) return [self.path + ' load_tests'] self.load_tests = load_tests def __eq__(self, other): return self.path == other.path loader._get_module_from_name = lambda name: Module(name) orig_load_tests = loader.loadTestsFromModule def loadTestsFromModule(module, pattern=None): # This is where load_tests is called. base = orig_load_tests(module, pattern=pattern) return base + [module.path + ' module tests'] loader.loadTestsFromModule = loadTestsFromModule loader.suiteClass = lambda thing: thing loader._top_level_dir = '/foo' # this time no '.py' on the pattern so that it can match # a test package suite = list(loader._find_tests('/foo', 'test*')) # We should have loaded tests from the a_directory and test_directory2 # directly and via load_tests for the test_directory package, which # still calls the baseline module loader. self.assertEqual(suite, [['a_directory module tests'], ['test_directory load_tests', 'test_directory module tests'], ['test_directory2 module tests']]) # The test module paths should be sorted for reliable execution order self.assertEqual(Module.paths, ['a_directory', 'test_directory', 'test_directory2']) # load_tests should have been called once with loader, tests and pattern # (but there are no tests in our stub module itself, so that is [] at # the time of call). self.assertEqual(Module.load_tests_args, [(loader, [], 'test*')]) def test_find_tests_default_calls_package_load_tests(self): loader = unittest.TestLoader() original_listdir = os.listdir def restore_listdir(): os.listdir = original_listdir original_isfile = os.path.isfile def restore_isfile(): os.path.isfile = original_isfile original_isdir = os.path.isdir def restore_isdir(): os.path.isdir = original_isdir directories = ['a_directory', 'test_directory', 'test_directory2'] path_lists = [directories, [], [], []] os.listdir = lambda path: path_lists.pop(0) self.addCleanup(restore_listdir) os.path.isdir = lambda path: True self.addCleanup(restore_isdir) os.path.isfile = lambda path: os.path.basename(path) not in directories self.addCleanup(restore_isfile) class Module(object): paths = [] load_tests_args = [] def __init__(self, path): self.path = path self.paths.append(path) if os.path.basename(path) == 'test_directory': def load_tests(loader, tests, pattern): self.load_tests_args.append((loader, tests, pattern)) return [self.path + ' load_tests'] self.load_tests = load_tests def __eq__(self, other): return self.path == other.path loader._get_module_from_name = lambda name: Module(name) orig_load_tests = loader.loadTestsFromModule def loadTestsFromModule(module, pattern=None): # This is where load_tests is called. base = orig_load_tests(module, pattern=pattern) return base + [module.path + ' module tests'] loader.loadTestsFromModule = loadTestsFromModule loader.suiteClass = lambda thing: thing loader._top_level_dir = '/foo' # this time no '.py' on the pattern so that it can match # a test package suite = list(loader._find_tests('/foo', 'test*.py')) # We should have loaded tests from the a_directory and test_directory2 # directly and via load_tests for the test_directory package, which # still calls the baseline module loader. self.assertEqual(suite, [['a_directory module tests'], ['test_directory load_tests', 'test_directory module tests'], ['test_directory2 module tests']]) # The test module paths should be sorted for reliable execution order self.assertEqual(Module.paths, ['a_directory', 'test_directory', 'test_directory2']) # load_tests should have been called once with loader, tests and pattern self.assertEqual(Module.load_tests_args, [(loader, [], 'test*.py')]) def test_find_tests_customize_via_package_pattern(self): # This test uses the example 'do-nothing' load_tests from # https://docs.python.org/3/library/unittest.html#load-tests-protocol # to make sure that that actually works. # Housekeeping original_listdir = os.listdir def restore_listdir(): os.listdir = original_listdir self.addCleanup(restore_listdir) original_isfile = os.path.isfile def restore_isfile(): os.path.isfile = original_isfile self.addCleanup(restore_isfile) original_isdir = os.path.isdir def restore_isdir(): os.path.isdir = original_isdir self.addCleanup(restore_isdir) self.addCleanup(sys.path.remove, abspath('/foo')) # Test data: we expect the following: # a listdir to find our package, and isfile and isdir checks on it. # a module-from-name call to turn that into a module # followed by load_tests. # then our load_tests will call discover() which is messy # but that finally chains into find_tests again for the child dir - # which is why we don't have an infinite loop. # We expect to see: # the module load tests for both package and plain module called, # and the plain module result nested by the package module load_tests # indicating that it was processed and could have been mutated. vfs = {abspath('/foo'): ['my_package'], abspath('/foo/my_package'): ['__init__.py', 'test_module.py']} def list_dir(path): return list(vfs[path]) os.listdir = list_dir os.path.isdir = lambda path: not path.endswith('.py') os.path.isfile = lambda path: path.endswith('.py') class Module(object): paths = [] load_tests_args = [] def __init__(self, path): self.path = path self.paths.append(path) if path.endswith('test_module'): def load_tests(loader, tests, pattern): self.load_tests_args.append((loader, tests, pattern)) return [self.path + ' load_tests'] else: def load_tests(loader, tests, pattern): self.load_tests_args.append((loader, tests, pattern)) # top level directory cached on loader instance __file__ = '/foo/my_package/__init__.py' this_dir = os.path.dirname(__file__) pkg_tests = loader.discover( start_dir=this_dir, pattern=pattern) return [self.path + ' load_tests', tests ] + pkg_tests self.load_tests = load_tests def __eq__(self, other): return self.path == other.path loader = unittest.TestLoader() loader._get_module_from_name = lambda name: Module(name) loader.suiteClass = lambda thing: thing loader._top_level_dir = abspath('/foo') # this time no '.py' on the pattern so that it can match # a test package suite = list(loader._find_tests(abspath('/foo'), 'test*.py')) # We should have loaded tests from both my_package and # my_package.test_module, and also run the load_tests hook in both. # (normally this would be nested TestSuites.) self.assertEqual(suite, [['my_package load_tests', [], ['my_package.test_module load_tests']]]) # Parents before children. self.assertEqual(Module.paths, ['my_package', 'my_package.test_module']) # load_tests should have been called twice with loader, tests and pattern self.assertEqual(Module.load_tests_args, [(loader, [], 'test*.py'), (loader, [], 'test*.py')]) def test_discover(self): loader = unittest.TestLoader() original_isfile = os.path.isfile original_isdir = os.path.isdir def restore_isfile(): os.path.isfile = original_isfile os.path.isfile = lambda path: False self.addCleanup(restore_isfile) orig_sys_path = sys.path[:] def restore_path(): sys.path[:] = orig_sys_path self.addCleanup(restore_path) full_path = os.path.abspath(os.path.normpath('/foo')) with self.assertRaises(ImportError): loader.discover('/foo/bar', top_level_dir='/foo') self.assertEqual(loader._top_level_dir, full_path) self.assertIn(full_path, sys.path) os.path.isfile = lambda path: True os.path.isdir = lambda path: True def restore_isdir(): os.path.isdir = original_isdir self.addCleanup(restore_isdir) _find_tests_args = [] def _find_tests(start_dir, pattern): _find_tests_args.append((start_dir, pattern)) return ['tests'] loader._find_tests = _find_tests loader.suiteClass = str suite = loader.discover('/foo/bar/baz', 'pattern', '/foo/bar') top_level_dir = os.path.abspath('/foo/bar') start_dir = os.path.abspath('/foo/bar/baz') self.assertEqual(suite, "['tests']") self.assertEqual(loader._top_level_dir, top_level_dir) self.assertEqual(_find_tests_args, [(start_dir, 'pattern')]) self.assertIn(top_level_dir, sys.path) def test_discover_start_dir_is_package_calls_package_load_tests(self): # This test verifies that the package load_tests in a package is indeed # invoked when the start_dir is a package (and not the top level). # http://bugs.python.org/issue22457 # Test data: we expect the following: # an isfile to verify the package, then importing and scanning # as per _find_tests' normal behaviour. # We expect to see our load_tests hook called once. vfs = {abspath('/toplevel'): ['startdir'], abspath('/toplevel/startdir'): ['__init__.py']} def list_dir(path): return list(vfs[path]) self.addCleanup(setattr, os, 'listdir', os.listdir) os.listdir = list_dir self.addCleanup(setattr, os.path, 'isfile', os.path.isfile) os.path.isfile = lambda path: path.endswith('.py') self.addCleanup(setattr, os.path, 'isdir', os.path.isdir) os.path.isdir = lambda path: not path.endswith('.py') self.addCleanup(sys.path.remove, abspath('/toplevel')) class Module(object): paths = [] load_tests_args = [] def __init__(self, path): self.path = path def load_tests(self, loader, tests, pattern): return ['load_tests called ' + self.path] def __eq__(self, other): return self.path == other.path loader = unittest.TestLoader() loader._get_module_from_name = lambda name: Module(name) loader.suiteClass = lambda thing: thing suite = loader.discover('/toplevel/startdir', top_level_dir='/toplevel') # We should have loaded tests from the package __init__. # (normally this would be nested TestSuites.) self.assertEqual(suite, [['load_tests called startdir']]) def setup_import_issue_tests(self, fakefile): listdir = os.listdir os.listdir = lambda _: [fakefile] isfile = os.path.isfile os.path.isfile = lambda _: True orig_sys_path = sys.path[:] def restore(): os.path.isfile = isfile os.listdir = listdir sys.path[:] = orig_sys_path self.addCleanup(restore) def setup_import_issue_package_tests(self, vfs): self.addCleanup(setattr, os, 'listdir', os.listdir) self.addCleanup(setattr, os.path, 'isfile', os.path.isfile) self.addCleanup(setattr, os.path, 'isdir', os.path.isdir) self.addCleanup(sys.path.__setitem__, slice(None), list(sys.path)) def list_dir(path): return list(vfs[path]) os.listdir = list_dir os.path.isdir = lambda path: not path.endswith('.py') os.path.isfile = lambda path: path.endswith('.py') def test_discover_with_modules_that_fail_to_import(self): loader = unittest.TestLoader() self.setup_import_issue_tests('test_this_does_not_exist.py') suite = loader.discover('.') self.assertIn(os.getcwd(), sys.path) self.assertEqual(suite.countTestCases(), 1) # Errors loading the suite are also captured for introspection. self.assertNotEqual([], loader.errors) self.assertEqual(1, len(loader.errors)) error = loader.errors[0] self.assertTrue( 'Failed to import test module: test_this_does_not_exist' in error, 'missing error string in %r' % error) test = list(list(suite)[0])[0] # extract test from suite with self.assertRaises(ImportError): test.test_this_does_not_exist() def test_discover_with_init_modules_that_fail_to_import(self): vfs = {abspath('/foo'): ['my_package'], abspath('/foo/my_package'): ['__init__.py', 'test_module.py']} self.setup_import_issue_package_tests(vfs) import_calls = [] def _get_module_from_name(name): import_calls.append(name) raise ImportError("Cannot import Name") loader = unittest.TestLoader() loader._get_module_from_name = _get_module_from_name suite = loader.discover(abspath('/foo')) self.assertIn(abspath('/foo'), sys.path) self.assertEqual(suite.countTestCases(), 1) # Errors loading the suite are also captured for introspection. self.assertNotEqual([], loader.errors) self.assertEqual(1, len(loader.errors)) error = loader.errors[0] self.assertTrue( 'Failed to import test module: my_package' in error, 'missing error string in %r' % error) test = list(list(suite)[0])[0] # extract test from suite with self.assertRaises(ImportError): test.my_package() self.assertEqual(import_calls, ['my_package']) # Check picklability for proto in range(pickle.HIGHEST_PROTOCOL + 1): pickle.loads(pickle.dumps(test, proto)) def test_discover_with_module_that_raises_SkipTest_on_import(self): if not unittest.BaseTestSuite._cleanup: raise unittest.SkipTest("Suite cleanup is disabled") loader = unittest.TestLoader() def _get_module_from_name(name): raise unittest.SkipTest('skipperoo') loader._get_module_from_name = _get_module_from_name self.setup_import_issue_tests('test_skip_dummy.py') suite = loader.discover('.') self.assertEqual(suite.countTestCases(), 1) result = unittest.TestResult() suite.run(result) self.assertEqual(len(result.skipped), 1) # Check picklability for proto in range(pickle.HIGHEST_PROTOCOL + 1): pickle.loads(pickle.dumps(suite, proto)) def test_discover_with_init_module_that_raises_SkipTest_on_import(self): if not unittest.BaseTestSuite._cleanup: raise unittest.SkipTest("Suite cleanup is disabled") vfs = {abspath('/foo'): ['my_package'], abspath('/foo/my_package'): ['__init__.py', 'test_module.py']} self.setup_import_issue_package_tests(vfs) import_calls = [] def _get_module_from_name(name): import_calls.append(name) raise unittest.SkipTest('skipperoo') loader = unittest.TestLoader() loader._get_module_from_name = _get_module_from_name suite = loader.discover(abspath('/foo')) self.assertIn(abspath('/foo'), sys.path) self.assertEqual(suite.countTestCases(), 1) result = unittest.TestResult() suite.run(result) self.assertEqual(len(result.skipped), 1) self.assertEqual(result.testsRun, 1) self.assertEqual(import_calls, ['my_package']) # Check picklability for proto in range(pickle.HIGHEST_PROTOCOL + 1): pickle.loads(pickle.dumps(suite, proto)) def test_command_line_handling_parseArgs(self): program = TestableTestProgram() args = [] program._do_discovery = args.append program.parseArgs(['something', 'discover']) self.assertEqual(args, [[]]) args[:] = [] program.parseArgs(['something', 'discover', 'foo', 'bar']) self.assertEqual(args, [['foo', 'bar']]) def test_command_line_handling_discover_by_default(self): program = TestableTestProgram() args = [] program._do_discovery = args.append program.parseArgs(['something']) self.assertEqual(args, [[]]) self.assertEqual(program.verbosity, 1) self.assertIs(program.buffer, False) self.assertIs(program.catchbreak, False) self.assertIs(program.failfast, False) def test_command_line_handling_discover_by_default_with_options(self): program = TestableTestProgram() args = [] program._do_discovery = args.append program.parseArgs(['something', '-v', '-b', '-v', '-c', '-f']) self.assertEqual(args, [[]]) self.assertEqual(program.verbosity, 2) self.assertIs(program.buffer, True) self.assertIs(program.catchbreak, True) self.assertIs(program.failfast, True) def test_command_line_handling_do_discovery_too_many_arguments(self): program = TestableTestProgram() program.testLoader = None with support.captured_stderr() as stderr, \ self.assertRaises(SystemExit) as cm: # too many args program._do_discovery(['one', 'two', 'three', 'four']) self.assertEqual(cm.exception.args, (2,)) self.assertIn('usage:', stderr.getvalue()) def test_command_line_handling_do_discovery_uses_default_loader(self): program = object.__new__(unittest.TestProgram) program._initArgParsers() class Loader(object): args = [] def discover(self, start_dir, pattern, top_level_dir): self.args.append((start_dir, pattern, top_level_dir)) return 'tests' program.testLoader = Loader() program._do_discovery(['-v']) self.assertEqual(Loader.args, [('.', 'test*.py', None)]) def test_command_line_handling_do_discovery_calls_loader(self): program = TestableTestProgram() class Loader(object): args = [] def discover(self, start_dir, pattern, top_level_dir): self.args.append((start_dir, pattern, top_level_dir)) return 'tests' program._do_discovery(['-v'], Loader=Loader) self.assertEqual(program.verbosity, 2) self.assertEqual(program.test, 'tests') self.assertEqual(Loader.args, [('.', 'test*.py', None)]) Loader.args = [] program = TestableTestProgram() program._do_discovery(['--verbose'], Loader=Loader) self.assertEqual(program.test, 'tests') self.assertEqual(Loader.args, [('.', 'test*.py', None)]) Loader.args = [] program = TestableTestProgram() program._do_discovery([], Loader=Loader) self.assertEqual(program.test, 'tests') self.assertEqual(Loader.args, [('.', 'test*.py', None)]) Loader.args = [] program = TestableTestProgram() program._do_discovery(['fish'], Loader=Loader) self.assertEqual(program.test, 'tests') self.assertEqual(Loader.args, [('fish', 'test*.py', None)]) Loader.args = [] program = TestableTestProgram() program._do_discovery(['fish', 'eggs'], Loader=Loader) self.assertEqual(program.test, 'tests') self.assertEqual(Loader.args, [('fish', 'eggs', None)]) Loader.args = [] program = TestableTestProgram() program._do_discovery(['fish', 'eggs', 'ham'], Loader=Loader) self.assertEqual(program.test, 'tests') self.assertEqual(Loader.args, [('fish', 'eggs', 'ham')]) Loader.args = [] program = TestableTestProgram() program._do_discovery(['-s', 'fish'], Loader=Loader) self.assertEqual(program.test, 'tests') self.assertEqual(Loader.args, [('fish', 'test*.py', None)]) Loader.args = [] program = TestableTestProgram() program._do_discovery(['-t', 'fish'], Loader=Loader) self.assertEqual(program.test, 'tests') self.assertEqual(Loader.args, [('.', 'test*.py', 'fish')]) Loader.args = [] program = TestableTestProgram() program._do_discovery(['-p', 'fish'], Loader=Loader) self.assertEqual(program.test, 'tests') self.assertEqual(Loader.args, [('.', 'fish', None)]) self.assertFalse(program.failfast) self.assertFalse(program.catchbreak) Loader.args = [] program = TestableTestProgram() program._do_discovery(['-p', 'eggs', '-s', 'fish', '-v', '-f', '-c'], Loader=Loader) self.assertEqual(program.test, 'tests') self.assertEqual(Loader.args, [('fish', 'eggs', None)]) self.assertEqual(program.verbosity, 2) self.assertTrue(program.failfast) self.assertTrue(program.catchbreak) def setup_module_clash(self): class Module(object): __file__ = 'bar/foo.py' sys.modules['foo'] = Module full_path = os.path.abspath('foo') original_listdir = os.listdir original_isfile = os.path.isfile original_isdir = os.path.isdir original_realpath = os.path.realpath def cleanup(): os.listdir = original_listdir os.path.isfile = original_isfile os.path.isdir = original_isdir os.path.realpath = original_realpath del sys.modules['foo'] if full_path in sys.path: sys.path.remove(full_path) self.addCleanup(cleanup) def listdir(_): return ['foo.py'] def isfile(_): return True def isdir(_): return True os.listdir = listdir os.path.isfile = isfile os.path.isdir = isdir if os.name == 'nt': # ntpath.realpath may inject path prefixes when failing to # resolve real files, so we substitute abspath() here instead. os.path.realpath = os.path.abspath return full_path def test_detect_module_clash(self): full_path = self.setup_module_clash() loader = unittest.TestLoader() mod_dir = os.path.abspath('bar') expected_dir = os.path.abspath('foo') msg = re.escape(r"'foo' module incorrectly imported from %r. Expected %r. " "Is this module globally installed?" % (mod_dir, expected_dir)) self.assertRaisesRegex( ImportError, '^%s$' % msg, loader.discover, start_dir='foo', pattern='foo.py' ) self.assertEqual(sys.path[0], full_path) def test_module_symlink_ok(self): full_path = self.setup_module_clash() original_realpath = os.path.realpath mod_dir = os.path.abspath('bar') expected_dir = os.path.abspath('foo') def cleanup(): os.path.realpath = original_realpath self.addCleanup(cleanup) def realpath(path): if path == os.path.join(mod_dir, 'foo.py'): return os.path.join(expected_dir, 'foo.py') return path os.path.realpath = realpath loader = unittest.TestLoader() loader.discover(start_dir='foo', pattern='foo.py') def test_discovery_from_dotted_path(self): loader = unittest.TestLoader() tests = [self] expectedPath = os.path.abspath(os.path.dirname(unittest.test.__file__)) self.wasRun = False def _find_tests(start_dir, pattern): self.wasRun = True self.assertEqual(start_dir, expectedPath) return tests loader._find_tests = _find_tests suite = loader.discover('unittest.test') self.assertTrue(self.wasRun) self.assertEqual(suite._tests, tests) def test_discovery_from_dotted_path_builtin_modules(self): loader = unittest.TestLoader() listdir = os.listdir os.listdir = lambda _: ['test_this_does_not_exist.py'] isfile = os.path.isfile isdir = os.path.isdir os.path.isdir = lambda _: False orig_sys_path = sys.path[:] def restore(): os.path.isfile = isfile os.path.isdir = isdir os.listdir = listdir sys.path[:] = orig_sys_path self.addCleanup(restore) with self.assertRaises(TypeError) as cm: loader.discover('sys') self.assertEqual(str(cm.exception), 'Can not use builtin modules ' 'as dotted module names') def test_discovery_failed_discovery(self): loader = unittest.TestLoader() package = types.ModuleType('package') def _import(packagename, *args, **kwargs): sys.modules[packagename] = package return package with unittest.mock.patch('builtins.__import__', _import): # Since loader.discover() can modify sys.path, restore it when done. with import_helper.DirsOnSysPath(): # Make sure to remove 'package' from sys.modules when done. with test.test_importlib.util.uncache('package'): with self.assertRaises(TypeError) as cm: loader.discover('package') self.assertEqual(str(cm.exception), 'don\'t know how to discover from {!r}' .format(package)) if __name__ == '__main__': unittest.main()