Fix typos in test in ffaa5b9b1ffb2575af8d305cc62f9757a5709f25 that masks the problem in issue #113.

Fix typos in test in ffaa5b9b1ffb2575af8d305cc62f9757a5709f25 that masks the problem in issue #113.

The line was incorrect for two reasons:

1. It checks `r` rather than `res`.
2. It does `assertTrue` rather than `assertEquals`.