0.16.0 breaks with AttributeError: ImageComparison object has no attribute result

[michaelbrundage]

pytest-mpl 0.15.0 was working for us, but pytest-mpl 0.16.0 has broken our tests with an error inside pytest-mpl.

On Python 3.9 running on my laptop, an example stack trace is:

_________________________________________________________ TimeSeriesDataOpsTest.test_plot _________________________________________________________

self = <pytest_mpl.plugin.ImageComparison object at 0x139932340>, item = <TestCaseFunction test_plot>

    @pytest.hookimpl(hookwrapper=True)
    def pytest_runtest_call(self, item):  # noqa
    
        compare = get_compare(item)
    
        if compare is None:
            yield
            return
    
        import matplotlib.pyplot as plt
        try:
            from matplotlib.testing.decorators import remove_ticks_and_titles
        except ImportError:
            from matplotlib.testing.decorators import ImageComparisonTest as MplImageComparisonTest
            remove_ticks_and_titles = MplImageComparisonTest.remove_text
    
        style = compare.kwargs.get('style', 'classic')
        remove_text = compare.kwargs.get('remove_text', False)
        backend = compare.kwargs.get('backend', 'agg')
    
        with plt.style.context(style, after_reset=True), switch_backend(backend):
    
            # Run test and get figure object
            yield
>           fig = self.result
E           AttributeError: 'ImageComparison' object has no attribute 'result'

/usr/local/lib/python3.9/site-packages/pytest_mpl/plugin.py:611: AttributeError
-------------------------------------------------------------- Captured stderr call ---------------------------------------------------------------

On Python 3.7 running on GitHub, this points to FigureCloser instead, but otherwise the same error:

self = <pytest_mpl.plugin.FigureCloser object at 0x7fa83e0c2dd0>
item = <TestCaseFunction test_plot>
    @pytest.hookimpl(hookwrapper=True)
    def pytest_runtest_call(self, item):
        yield
        if get_compare(item) is not None:
>           close_mpl_figure(self.result)
E           AttributeError: 'FigureCloser' object has no attribute 'result'
/opt/hostedtoolcache/Python/3.7.13/x64/lib/python3.7/site-packages/pytest_mpl/plugin.py:740: AttributeError

Failed Github Action

[ConorMacBride]

Thanks for the bug report @michaelbrundage! 👍 The latest pytest-mpl release made some changes to how it integrates with pytest, however, it turns out the way it integrates is ignored when unittest.TestCase is used. #171 should fix this issue. I've tested the PR branch on Kats and no errors are raised. We'll hopefully get a bugfix release out soon!

[michaelbrundage]

Great, thanks @ConorMacBride!