    @Test
    public void testCheckQuality() {

        assertTrue(wd.checkQuality("Y"));
        assertTrue(wd.checkQuality("N"));
        assertTrue(wd.checkQuality("S"));
        assertTrue(wd.checkQuality("F"));
        assertFalse(wd.checkQuality("I"));
        assertFalse(wd.checkQuality(""));
    }