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How to use _assert_warns_context_manager method in Testify

Best Python code snippet using Testify_python

assertions.py

Source:assertions.py

...557    if len(true_args) != 1:558        raise AssertionError("Expected exactly one True (got %d) args: %r" % (len(true_args), args))559    return true_args[0]560@contextlib.contextmanager561def _assert_warns_context_manager(warning_class=None, warnings_test=None):562    """563    Builds a context manager for testing code that should throw a warning.564    This will look for a given class, call a custom test, or both.565    Args:566        warning_class - a class or subclass of Warning. If not None, then567            the context manager will raise an AssertionError if the block568            does not throw at least one warning of that type.569        warnings_test - a function which takes a list of warnings caught,570            and makes a number of assertions about the result. If the function571            returns without an exception, the context manager will consider572            this a successful assertion.573    """574    with warnings.catch_warnings(record=True) as caught:575        # All warnings should be triggered.576        warnings.resetwarnings()577        if warning_class:578            warnings.simplefilter('ignore')579            warnings.simplefilter('always', category=warning_class)580        else:581            warnings.simplefilter('always')582        # Do something that ought to trigger a warning.583        yield584        # We should have received at least one warning.585        assert_gt(len(caught), 0, 'expected at least one warning to be thrown')586        # Run the custom test against the warnings we caught.587        if warnings_test:588            warnings_test(caught)589def assert_warns(warning_class=None, callable=None, *args, **kwargs):590    """Assert that the given warning class is thrown as a context manager591    or by passing in a callable and its arguments.592    As a context manager:593    >>> with assert_warns():594    ...     warnings.warn('Hey!')595    Passing in a callable:596    >>> def throw_warning():597    ...     warnings.warn('Hey!')598    >>> assert_warns(UserWarning, throw_warning)599    """600    if callable is None:601        return _assert_warns_context_manager(warning_class=warning_class)602    else:603        with _assert_warns_context_manager(warning_class=warning_class):604            callable(*args, **kwargs)605def assert_warns_such_that(warnings_test, callable=None, *args, **kwargs):606    """607    Assert that the given warnings_test function returns True when608    called with a full list of warnings that were generated by either609    a code block (when this is used as a context manager in a `with` statement)610    or the given callable (when called with the appropriate args and kwargs).611    As a context manager:612    >>> def two_warnings_thrown(warnings):613    ...     assert len(warnings) == 2614    >>> with assert_warns_such_that(two_warnings_thrown):615    ...     warnings.warn('Hey!')616    ...     warnings.warn('Seriously!')617    Passing in a callable:618    >>> def throw_warnings(count):619    ...     for n in range(count):620    ...         warnings.warn('Warning #%i' % n)621    >>> assert_warns_such_that(two_warnings_thrown, throw_warnings, 2)622    """623    if callable is None:624        return _assert_warns_context_manager(warnings_test=warnings_test)625    else:626        with _assert_warns_context_manager(warnings_test=warnings_test):627            callable(*args, **kwargs)628def _to_characters(x):629    """Return characters that represent the object `x`, come hell or high water."""630    if isinstance(x, six.text_type):631        return x632    try:633        return six.text_type(x, 'UTF-8')634    except UnicodeDecodeError:635        return six.text_type(x, 'latin1')636    except TypeError:637        # We're only allowed to specify an encoding for str values, for whatever reason.638        try:639            return six.text_type(x)640        except UnicodeDecodeError:...

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