def test_animation_repr_html(writer, html, want, anim):                                                                                                                                                                                                                                                     
    if (writer == 'imagemagick' and html == 'html5'                                                                                                                                                                                                                                                         
            # ImageMagick delegates to ffmpeg for this format.                                                                                                                                                                                                                                              
            and not animation.FFMpegWriter.isAvailable()):                                                                                                                                                                                                                                                  
        pytest.skip('Requires FFMpeg')                                                                                                                                                                                                                                                                      
    # create here rather than in the fixture otherwise we get __del__ warnings                                                                                                                                                                                                                              
    # about producing no output                                                                                                                                                                                                                                                                             
    anim = animation.FuncAnimation(**anim)                                                                                                                                                                                                                                                                  
    with plt.rc_context({'animation.writer': writer,                                                                                                                                                                                                                                                        
                         'animation.html': html}):                                                                                                                                                                                                                                                          
        html = anim._repr_html_()                                                                                                                                                                                                                                                                           
    if want is None:                                                                                                                                                                                                                                                                                        
        assert html is None                                                                                                                                                                                                                                                                                 
        import warnings                                                                                                                                                                                                                                                                                     
        with warnings.catch_warnings(record=True) as w:                                                                                                                                                                                                                                                     
            warnings.simplefilter("always")                                                                                                                                                                                                                                                                 
            wranim = weakref.ref(anim)                      
            del anim  # Animation was never run, so will warn on cleanup.                                                                                                                                                                                                                                   
            print(wranim())                                                                                                                                                                                                                                                                                 
            np.testing.break_cycles()                                                                                                                                                                                                                                                                       
            print(wranim())                                                                                                                                                                                                                                                                                 
            assert len(w) == 1                                                                                                                                                                                                                                                                              
            assert issubclass(w[0], UserWarning)                                                                                                                                                                                                                                                            
    else:                                                                                                                                                                                                                                                                                                   
        assert want in html