| 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. | |