# Copyright 2007 Google, Inc. All Rights Reserved. # Licensed to PSF under a Contributor Agreement. """Tests for the raise statement.""" from test import support, script_helper import re import sys import types import unittest try: from resource import setrlimit, RLIMIT_CORE, error as resource_error except ImportError: prepare_subprocess = None else: def prepare_subprocess(): # don't create core file try: setrlimit(RLIMIT_CORE, (0, 0)) except (ValueError, resource_error): pass def get_tb(): try: raise OSError() except: return sys.exc_info()[2] class Context: def __enter__(self): return self def __exit__(self, exc_type, exc_value, exc_tb): return True class TestRaise(unittest.TestCase): def test_invalid_reraise(self): try: raise except RuntimeError as e: self.assertIn("No active exception", str(e)) else: self.fail("No exception raised") def test_reraise(self): try: try: raise IndexError() except IndexError as e: exc1 = e raise except IndexError as exc2: self.assertTrue(exc1 is exc2) else: self.fail("No exception raised") def test_except_reraise(self): def reraise(): try: raise TypeError("foo") except: try: raise KeyError("caught") except KeyError: pass raise self.assertRaises(TypeError, reraise) def test_finally_reraise(self): def reraise(): try: raise TypeError("foo") except: try: raise KeyError("caught") finally: raise self.assertRaises(KeyError, reraise) def test_nested_reraise(self): def nested_reraise(): raise def reraise(): try: raise TypeError("foo") except: nested_reraise() self.assertRaises(TypeError, reraise) def test_raise_from_None(self): try: try: raise TypeError("foo") except: raise ValueError() from None except ValueError as e: self.assertTrue(isinstance(e.__context__, TypeError)) self.assertIsNone(e.__cause__) def test_with_reraise1(self): def reraise(): try: raise TypeError("foo") except: with Context(): pass raise self.assertRaises(TypeError, reraise) def test_with_reraise2(self): def reraise(): try: raise TypeError("foo") except: with Context(): raise KeyError("caught") raise self.assertRaises(TypeError, reraise) def test_yield_reraise(self): def reraise(): try: raise TypeError("foo") except: yield 1 raise g = reraise() next(g) self.assertRaises(TypeError, lambda: next(g)) self.assertRaises(StopIteration, lambda: next(g)) def test_erroneous_exception(self): class MyException(Exception): def __init__(self): raise RuntimeError() try: raise MyException except RuntimeError: pass else: self.fail("No exception raised") def test_new_returns_invalid_instance(self): # See issue #11627. class MyException(Exception): def __new__(cls, *args): return object() with self.assertRaises(TypeError): raise MyException def test_assert_with_tuple_arg(self): try: assert False, (3,) except AssertionError as e: self.assertEqual(str(e), "(3,)") class TestCause(unittest.TestCase): def testCauseSyntax(self): try: try: try: raise TypeError except Exception: raise ValueError from None except ValueError as exc: self.assertIsNone(exc.__cause__) raise exc from Ellipsis except ValueError as exc: e = exc self.assertIs(e.__cause__, Ellipsis) self.assertIsInstance(e.__context__, TypeError) def test_invalid_cause(self): try: raise IndexError from 5 except TypeError as e: self.assertIn("exception cause", str(e)) else: self.fail("No exception raised") def test_class_cause(self): try: raise IndexError from KeyError except IndexError as e: self.assertIsInstance(e.__cause__, KeyError) else: self.fail("No exception raised") def test_instance_cause(self): cause = KeyError() try: raise IndexError from cause except IndexError as e: self.assertTrue(e.__cause__ is cause) else: self.fail("No exception raised") def test_erroneous_cause(self): class MyException(Exception): def __init__(self): raise RuntimeError() try: raise IndexError from MyException except RuntimeError: pass else: self.fail("No exception raised") class TestTraceback(unittest.TestCase): def get_output(self, code, filename=None): """ Run the specified code in Python (in a new child process) and read the output from the standard error or from a file (if filename is set). Return the output lines as a list. """ options = {} if prepare_subprocess: options['preexec_fn'] = prepare_subprocess process = script_helper.spawn_python('-c', code, **options) stdout, stderr = process.communicate() exitcode = process.wait() output = support.strip_python_stderr(stdout) output = output.decode('ascii', 'backslashreplace') if filename: self.assertEqual(output, '') with open(filename, "rb") as fp: output = fp.read() output = output.decode('ascii', 'backslashreplace') output = re.sub('Current thread 0x[0-9a-f]+', 'Current thread XXX', output) return output.splitlines(), exitcode def test_traceback_verbiage(self): code = """ try: raise ValueError except: raise NameError from None """ text, exitcode = self.get_output(code) self.assertEqual(len(text), 3) self.assertTrue(text[0].startswith('Traceback')) self.assertTrue(text[1].startswith(' File ')) self.assertTrue(text[2].startswith('NameError')) def test_sets_traceback(self): try: raise IndexError() except IndexError as e: self.assertIsInstance(e.__traceback__, types.TracebackType) else: self.fail("No exception raised") def test_accepts_traceback(self): tb = get_tb() try: raise IndexError().with_traceback(tb) except IndexError as e: self.assertNotEqual(e.__traceback__, tb) self.assertEqual(e.__traceback__.tb_next, tb) else: self.fail("No exception raised") class TestContext(unittest.TestCase): def test_instance_context_instance_raise(self): context = IndexError() try: try: raise context except: raise OSError() except OSError as e: self.assertEqual(e.__context__, context) else: self.fail("No exception raised") def test_class_context_instance_raise(self): context = IndexError try: try: raise context except: raise OSError() except OSError as e: self.assertNotEqual(e.__context__, context) self.assertIsInstance(e.__context__, context) else: self.fail("No exception raised") def test_class_context_class_raise(self): context = IndexError try: try: raise context except: raise OSError except OSError as e: self.assertNotEqual(e.__context__, context) self.assertIsInstance(e.__context__, context) else: self.fail("No exception raised") def test_c_exception_context(self): try: try: 1/0 except: raise OSError except OSError as e: self.assertIsInstance(e.__context__, ZeroDivisionError) else: self.fail("No exception raised") def test_c_exception_raise(self): try: try: 1/0 except: xyzzy except NameError as e: self.assertIsInstance(e.__context__, ZeroDivisionError) else: self.fail("No exception raised") def test_noraise_finally(self): try: try: pass finally: raise OSError except OSError as e: self.assertTrue(e.__context__ is None) else: self.fail("No exception raised") def test_raise_finally(self): try: try: 1/0 finally: raise OSError except OSError as e: self.assertIsInstance(e.__context__, ZeroDivisionError) else: self.fail("No exception raised") def test_context_manager(self): class ContextManager: def __enter__(self): pass def __exit__(self, t, v, tb): xyzzy try: with ContextManager(): 1/0 except NameError as e: self.assertIsInstance(e.__context__, ZeroDivisionError) else: self.fail("No exception raised") def test_cycle_broken(self): # Self-cycles (when re-raising a caught exception) are broken try: try: 1/0 except ZeroDivisionError as e: raise e except ZeroDivisionError as e: self.assertTrue(e.__context__ is None, e.__context__) def test_reraise_cycle_broken(self): # Non-trivial context cycles (through re-raising a previous exception) # are broken too. try: try: xyzzy except NameError as a: try: 1/0 except ZeroDivisionError: raise a except NameError as e: self.assertTrue(e.__context__.__context__ is None) def test_3118(self): # deleting the generator caused the __context__ to be cleared def gen(): try: yield 1 finally: pass def f(): g = gen() next(g) try: try: raise ValueError except: del g raise KeyError except Exception as e: self.assertIsInstance(e.__context__, ValueError) f() def test_3611(self): # A re-raised exception in a __del__ caused the __context__ # to be cleared class C: def __del__(self): try: 1/0 except: raise def f(): x = C() try: try: x.x except AttributeError: del x raise TypeError except Exception as e: self.assertNotEqual(e.__context__, None) self.assertIsInstance(e.__context__, AttributeError) with support.captured_output("stderr"): f() class TestRemovedFunctionality(unittest.TestCase): def test_tuples(self): try: raise (IndexError, KeyError) # This should be a tuple! except TypeError: pass else: self.fail("No exception raised") def test_strings(self): try: raise "foo" except TypeError: pass else: self.fail("No exception raised") def test_main(): support.run_unittest(__name__) if __name__ == "__main__": unittest.main()