def METHOD_NAME(self):
    pattern_view = self.widget.pattern_widget
    self.load_phase('au_Anderson.jcpds')
    pattern_view.view_box.setRange(xRange=[17, 30])
    pattern_view.emit_sig_range_changed()
    phase_plot = pattern_view.phases[0]
    line_heights = []
    for line in phase_plot.line_items:
        line_data = line.getData()
        if (line_data[0][0] > 17) and (line_data[0][1] < 30):
            height = line_data[1][1] - line_data[1][0]
            line_heights.append(height)
    pattern_view_range = pattern_view.view_box.viewRange()
    pattern_x, pattern_y = pattern_view.plot_item.getData()
    pattern_y_max_in_range = np.max(pattern_y[(pattern_x > pattern_view_range[0][0]) &
                                              (pattern_x < pattern_view_range[0][1])])
    expected_maximum_height = pattern_y_max_in_range - pattern_view_range[1][0]
    self.assertAlmostEqual(expected_maximum_height, np.max(line_heights))