Add test to verify last update

Signed-off-by: Shahbaz Youssefi <ShabbyX@gmail.com>
Add cosld test

This shows a bug with SLD!  The SLD should indeed go in infinite loop,
but it outputs contradicting results such as:

I = z, I = s(z).

which shouldn't have happened.

Signed-off-by: Shahbaz Youssefi <ShabbyX@gmail.com>