@Test
public void firstNAdd() {
Transformers.<MyObject>firstN(Properties.constant(1)).transform(fromList, toList);
fromList.add(new MyObject("x"));
fromList.add(0, new MyObject("y"));
assertEquals("[y]", toList.toString());
}
@Test
public void targetHasNoMoreThanNElements() {
ObservableSingleItemList<MyObject> targetList = new ObservableSingleItemList<>();
fromList.add(new MyObject("x"));
Transformers.<MyObject>firstN(Properties.constant(1)).transform(fromList, targetList);
fromList.add(0, new MyObject("y"));
assertEquals("[y]", targetList.toString());
}
@Test
public void firstNInitial() {
fromList.add(new MyObject("a"));
fromList.add(new MyObject("b"));
fromList.add(new MyObject("c"));
Transformers.<MyObject>firstN(Properties.constant(2)).transform(fromList, toList);
assertEquals("[a, b]", toList.toString());
}
@Test
public void firstNRemove() {
fromList.add(new MyObject("a"));
fromList.add(new MyObject("b"));
fromList.add(new MyObject("c"));
Transformers.<MyObject>firstN(Properties.constant(1)).transform(fromList, toList);
fromList.remove(2);
fromList.remove(0);
assertEquals("[b]", toList.toString());
}
@Test
public void firstNdecreaseN() {
fromList.add(new MyObject("a"));
fromList.add(new MyObject("b"));
fromList.add(new MyObject("c"));
ValueProperty<Integer> prop = new ValueProperty<>(2);
Transformers.<MyObject>firstN(prop).transform(fromList, toList);
prop.set(0);
assertEquals("[]", toList.toString());
}