From b5a7a4f0c20717a4c92c371583b5521b83f40f32 Mon Sep 17 00:00:00 2001 From: Samuel Freilich Date: Tue, 24 Sep 2019 15:08:31 -0400 Subject: [PATCH] bpo-36871: Handle spec errors in assert_has_calls (GH-16005) The fix in PR 13261 handled the underlying issue about the spec for specific methods not being applied correctly, but it didn't fix the issue that was causing the misleading error message. The code currently grabs a list of responses from _call_matcher (which may include exceptions). But it doesn't reach inside the list when checking if the result is an exception. This results in a misleading error message when one of the provided calls does not match the spec. https://bugs.python.org/issue36871 Automerge-Triggered-By: @gpshead --- Lib/unittest/mock.py | 26 +++++++++++++++---- Lib/unittest/test/testmock/testasync.py | 21 +++++++++++++++ Lib/unittest/test/testmock/testmock.py | 19 ++++++++++++++ .../2019-09-24-18-45-46.bpo-36871.p47knk.rst | 3 +++ 4 files changed, 64 insertions(+), 5 deletions(-) create mode 100644 Misc/NEWS.d/next/Core and Builtins/2019-09-24-18-45-46.bpo-36871.p47knk.rst diff --git a/Lib/unittest/mock.py b/Lib/unittest/mock.py index 22d63a45884..7bd11c8e703 100644 --- a/Lib/unittest/mock.py +++ b/Lib/unittest/mock.py @@ -926,13 +926,21 @@ class NonCallableMock(Base): If `any_order` is True then the calls can be in any order, but they must all appear in `mock_calls`.""" expected = [self._call_matcher(c) for c in calls] - cause = expected if isinstance(expected, Exception) else None + cause = next((e for e in expected if isinstance(e, Exception)), None) all_calls = _CallList(self._call_matcher(c) for c in self.mock_calls) if not any_order: if expected not in all_calls: + if cause is None: + problem = 'Calls not found.' + else: + problem = ('Error processing expected calls.\n' + 'Errors: {}').format( + [e if isinstance(e, Exception) else None + for e in expected]) raise AssertionError( - 'Calls not found.\nExpected: %r%s' - % (_CallList(calls), self._calls_repr(prefix="Actual")) + f'{problem}\n' + f'Expected: {_CallList(calls)}\n' + f'Actual: {self._calls_repr(prefix="Actual")}' ) from cause return @@ -2244,12 +2252,20 @@ class AsyncMockMixin(Base): they must all appear in :attr:`await_args_list`. """ expected = [self._call_matcher(c) for c in calls] - cause = expected if isinstance(expected, Exception) else None + cause = next((e for e in expected if isinstance(e, Exception)), None) all_awaits = _CallList(self._call_matcher(c) for c in self.await_args_list) if not any_order: if expected not in all_awaits: + if cause is None: + problem = 'Awaits not found.' + else: + problem = ('Error processing expected awaits.\n' + 'Errors: {}').format( + [e if isinstance(e, Exception) else None + for e in expected]) raise AssertionError( - f'Awaits not found.\nExpected: {_CallList(calls)}\n' + f'{problem}\n' + f'Expected: {_CallList(calls)}\n' f'Actual: {self.await_args_list}' ) from cause return diff --git a/Lib/unittest/test/testmock/testasync.py b/Lib/unittest/test/testmock/testasync.py index aca1cd0bbec..f951526dbeb 100644 --- a/Lib/unittest/test/testmock/testasync.py +++ b/Lib/unittest/test/testmock/testasync.py @@ -1,5 +1,6 @@ import asyncio import inspect +import re import unittest from unittest.mock import (ANY, call, AsyncMock, patch, MagicMock, @@ -889,3 +890,23 @@ class AsyncMockAssert(unittest.TestCase): asyncio.run(self._runnable_test()) with self.assertRaises(AssertionError): self.mock.assert_not_awaited() + + def test_assert_has_awaits_not_matching_spec_error(self): + async def f(): pass + + mock = AsyncMock(spec=f) + + with self.assertRaisesRegex( + AssertionError, + re.escape('Awaits not found.\nExpected:')) as cm: + mock.assert_has_awaits([call()]) + self.assertIsNone(cm.exception.__cause__) + + with self.assertRaisesRegex( + AssertionError, + re.escape('Error processing expected awaits.\n' + "Errors: [None, TypeError('too many positional " + "arguments')]\n" + 'Expected:')) as cm: + mock.assert_has_awaits([call(), call('wrong')]) + self.assertIsInstance(cm.exception.__cause__, TypeError) diff --git a/Lib/unittest/test/testmock/testmock.py b/Lib/unittest/test/testmock/testmock.py index ad67f98f87c..88807d71ccb 100644 --- a/Lib/unittest/test/testmock/testmock.py +++ b/Lib/unittest/test/testmock/testmock.py @@ -1435,6 +1435,25 @@ class MockTest(unittest.TestCase): mock.assert_has_calls(calls[:-1]) mock.assert_has_calls(calls[:-1], any_order=True) + def test_assert_has_calls_not_matching_spec_error(self): + def f(): pass + + mock = Mock(spec=f) + + with self.assertRaisesRegex( + AssertionError, + re.escape('Calls not found.\nExpected:')) as cm: + mock.assert_has_calls([call()]) + self.assertIsNone(cm.exception.__cause__) + + with self.assertRaisesRegex( + AssertionError, + re.escape('Error processing expected calls.\n' + "Errors: [None, TypeError('too many positional " + "arguments')]\n" + 'Expected:')) as cm: + mock.assert_has_calls([call(), call('wrong')]) + self.assertIsInstance(cm.exception.__cause__, TypeError) def test_assert_any_call(self): mock = Mock() diff --git a/Misc/NEWS.d/next/Core and Builtins/2019-09-24-18-45-46.bpo-36871.p47knk.rst b/Misc/NEWS.d/next/Core and Builtins/2019-09-24-18-45-46.bpo-36871.p47knk.rst new file mode 100644 index 00000000000..6b7b19a0d57 --- /dev/null +++ b/Misc/NEWS.d/next/Core and Builtins/2019-09-24-18-45-46.bpo-36871.p47knk.rst @@ -0,0 +1,3 @@ +Improve error handling for the assert_has_calls and assert_has_awaits methods of +mocks. Fixed a bug where any errors encountered while binding the expected calls +to the mock's spec were silently swallowed, leading to misleading error output.