[New-bugs-announce] [issue30949] Provide assertion functions in unittest.mock

[Daniel Watkins]

New submission from Daniel Watkins:

The convenience assertion methods on mock objects can be easily mistyped and if they are mistyped, they will silently pass.  This can be quite user-hostile.  Consider the following:

>>> example = Mock()
>>> example.assert_called_once()
>>> example.assert_caled_once_with(...)

This will not raise any exceptions, though the first feels natural and the latter is misspelt.  To avoid using the methods, one can type:

>>> example = Mock()
>>> assert example.call_count == 1
>>> assert example.call_args_list == [call(...)]

but the meaning of that latter statement is particularly non-obvious.  Instead, it would be great if I could import the assertions from mock as functions, and call them with mock as the first argument:

>>> from unittest.mock import assert_called_once  # This will be an ImportError
>>> example = Mock()
>>> assert_caled_once_with(example, ...)  # A NameError
>>> assert_called_once_with(example, ...)  # Great success!

----------
components: Tests
messages: 298533
nosy: odd_bloke
priority: normal
severity: normal
status: open
title: Provide assertion functions in unittest.mock
versions: Python 3.7

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue30949>
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