public static void assertRetain(int expectedRetainCount, boolean expectedHasTrailingNewline,
DocOp op, int index) {
DocOpComponent component = op.getComponents().get(index);
assertEquals(RETAIN, component.getType());
Retain retain = (Retain) component;
assertEquals(expectedRetainCount, retain.getCount());
assertEquals(expectedHasTrailingNewline, retain.hasTrailingNewline());
}