def METHOD_NAME(self, plot, start, end):
    print(plot.handles)
    arrow_glyph = plot.handles['arrow_1_glyph']
    arrow_cds = plot.handles['arrow_1_source']
    label_glyph = plot.handles['text_1_glyph']
    label_cds = plot.handles['text_1_source']
    x0, y0 = start
    x1, y1 = end
    self.assertEqual(label_glyph.x, 'x')
    self.assertEqual(label_glyph.y, 'y')
    self.assertEqual(label_cds.data, {'x': [x0], 'y': [y0], 'text': ['Test']})
    self.assertEqual(arrow_glyph.x_start, 'x_start')
    self.assertEqual(arrow_glyph.y_start, 'y_start')
    self.assertEqual(arrow_glyph.x_end, 'x_end')
    self.assertEqual(arrow_glyph.y_end, 'y_end')
    self.assertEqual(arrow_cds.data, {'x_start': [x0], 'x_end': [x1],
                                      'y_start': [y0], 'y_end': [y1]})