public void testEquals() {
        
        DateAxis a1 = new DateAxis("Test");
        DateAxis a2 = new DateAxis("Test");
        assertTrue(a1.equals(a2));
        assertFalse(a1.equals(null));
        assertFalse(a1.equals("Some non-DateAxis object"));
        
        // tickUnit 
        a1.setTickUnit(new DateTickUnit(DateTickUnit.DAY, 7));
        assertFalse(a1.equals(a2));
        a2.setTickUnit(new DateTickUnit(DateTickUnit.DAY, 7));
        assertTrue(a1.equals(a2));

        // dateFormatOverride 
        a1.setDateFormatOverride(new SimpleDateFormat("yyyy"));
        assertFalse(a1.equals(a2));
        a2.setDateFormatOverride(new SimpleDateFormat("yyyy"));
        assertTrue(a1.equals(a2));

        // tickMarkPosition
        a1.setTickMarkPosition(DateTickMarkPosition.END);
        assertFalse(a1.equals(a2));
        a2.setTickMarkPosition(DateTickMarkPosition.END);
        assertTrue(a1.equals(a2));
        
        // timeline
        a1.setTimeline(SegmentedTimeline.newMondayThroughFridayTimeline());
        assertFalse(a1.equals(a2));
        a2.setTimeline(SegmentedTimeline.newMondayThroughFridayTimeline());
        assertTrue(a1.equals(a2));