================================== FAILURES ===================================
____________________________ test_dpi_ratio_change ____________________________
[gw0] win32 -- Python 3.6.7 c:\miniconda36-x64\envs\test-environment\python.exe
    @pytest.mark.backend('Qt5Agg')
    def test_dpi_ratio_change():
        """
        Make sure that if _dpi_ratio changes, the figure dpi changes but the
        widget remains the same physical size.
        """
    
        prop = 'matplotlib.backends.backend_qt5.FigureCanvasQT._dpi_ratio'
    
        with mock.patch(prop, new_callable=mock.PropertyMock) as p:
    
            p.return_value = 3
    
            fig = plt.figure(figsize=(5, 2), dpi=120)
            qt_canvas = fig.canvas
            qt_canvas.show()
    
            from matplotlib.backends.backend_qt5 import qApp
    
            # Make sure the mocking worked
            assert qt_canvas._dpi_ratio == 3
    
            size = qt_canvas.size()
    
            qt_canvas.manager.show()
            qt_canvas.draw()
            qApp.processEvents()
    
            # The DPI and the renderer width/height change
            assert fig.dpi == 360
            assert qt_canvas.renderer.width == 1800
            assert qt_canvas.renderer.height == 720
    
            # The actual widget size and figure physical size don't change
            assert size.width() == 600
            assert size.height() == 240
            assert qt_canvas.get_width_height() == (600, 240)
            assert (fig.get_size_inches() == (5, 2)).all()
    
            p.return_value = 2
    
            assert qt_canvas._dpi_ratio == 2
    
            qt_canvas.draw()
            qApp.processEvents()
            # this second processEvents is required to fully run the draw.
            # On `update` we notice the DPI has changed and trigger a
            # resize event to refresh, the second processEvents is
            # required to process that and fully update the window sizes.
            qApp.processEvents()
    
            # The DPI and the renderer width/height change
            assert fig.dpi == 240
            assert qt_canvas.renderer.width == 1200
>           assert qt_canvas.renderer.height == 480
E           assert 474.0 == 480
E            +  where 474.0 = <matplotlib.backends.backend_agg.RendererAgg object at 0x000000CC215AE2B0>.height