assertEquals("this is", stream.next());
assertTrue(stream.mergeWithPrevious());
assertEquals("this is a", stream.next());
assertTrue(stream.mergeWithPrevious());
assertEquals("this is a test", stream.next());
assertTrue(stream.mergeWithPrevious());
assertEquals("this is a test stream", stream.next());
assertFalse(stream.mergeWithPrevious());
stream = null;
}