@Test
public void works_with_a_single_type() {
final Stream<Integer> stream = Streams.of(6, 3, 2, 7);
assertThat(stream.foldLeft(summation(), 0), is(18));
}
@Test
public void works_with_multiple_types() {
final Stream<Integer> stream = Streams.of(6, 3, 2, 7);
assertThat(stream.foldLeft(joinAsString(), ""), is(", 6, 3, 2, 7"));
}
@Test
public void retains_order() {
final Stream<Integer> stream = Streams.of(3, 2, 1);
assertThat(stream.toList(), contains(3, 2, 1));
}
@Test
public void retains_duplicates() {
final Stream<Integer> stream = Streams.of(2, 3, 2, 1);
assertThat(stream.toList(), contains(2, 3, 2, 1));
}
@Test
public void strips_duplicates_out_of_a_stream() {
final Stream<Integer> stream = Streams.of(7, 2, 5, 7, 7, 9, 4, 5, 2);
assertThat(stream.unique(), contains(7, 2, 5, 9, 4));
}
@Test
public void converts_a_stream_to_an_equivalent_list() {
final Stream<Integer> stream = Streams.of(1, 2, 3);
assertThat(stream.toList(), contains(1, 2, 3));
}
@Test
public void makes_no_changes_to_an_already_unique_stream() {
final Stream<Integer> stream = Streams.of(7, 2, 5, 9, 4);
assertThat(stream.unique(), contains(7, 2, 5, 9, 4));
}
@Test
public void is_lazy() {
final Stream<Object> stream = Streams.wrap(new ThrowingIterator());
stream.unique();
}
@Override
public Stream<T> determineTail() {
return !one.isEmpty() ? new Concat<T>(one.tail(), two) : two.tail();
}
@Override
public T determineHead() {
return !one.isEmpty() ? one.head() : two.head();
}
@Override
public boolean determineIsEmpty() {
return one.isEmpty() && two.isEmpty();
}