def METHOD_NAME(self):
    # checks that the axis extent is narrowed when doing a subselection
    axis = "altitude"
    slc = yt.SlicePlot(self.ds, axis, ("stream", "Density"), origin="native")
    ax = slc.plots[("stream", "Density")].axes
    full_extent = np.abs(ax.get_extent())
    slc = yt.SlicePlot(
        self.ds, axis, ("stream", "Density"), origin="native", width=(80.0, 50.0)
    )
    ax = slc.plots[("stream", "Density")].axes
    extent = np.abs(ax.get_extent())
    assert np.all(extent < full_extent)