plot1.setAngleGridlinePaint(new GradientPaint(1.0f, 2.0f, Color.red,
                3.0f, 4.0f, Color.blue));
        assertFalse(plot1.equals(plot2));
        plot2.setAngleGridlinePaint(new GradientPaint(1.0f, 2.0f, Color.red,
                3.0f, 4.0f, Color.blue));
        assertTrue(plot1.equals(plot2));