@Test
public void verifyToString() {

	Preference pref = new Preference( null, null, null );
	Assert.assertNull( pref.toString());
	pref = new Preference( "key", "value", null );
	Assert.assertEquals( "key", pref.toString());
	for( PreferenceKeyCategory cat : PreferenceKeyCategory.values()) {
		Assert.assertNotNull( cat.toString());
		Assert.assertNotNull( cat.getDescription());
	}
}