
PASS Calling observe() without 'type' or 'entryTypes' throws a TypeError
PASS Calling observe() with entryTypes and then type should throw an InvalidModificationError
PASS Calling observe() with type and then entryTypes should throw an InvalidModificationError
PASS Calling observe() with type and entryTypes should throw a TypeError
PASS Passing in unknown values to type does throw an exception.
PASS observe() with different type values stacks.