review unit tests

[jhcepas]

While refactoring I found a few test cases that where returning True when actually the result was incorrect. Let's try to double check all the unitests little by little.
It is very important that we can trust them

[AlishaMechtley]

All the unittests have been checked

[jhcepas]

I only reviewed a couple that were failing after refactoring. Checks still needed for the rest :)

[AlishaMechtley]

I check all of them and added lines that check for the specific nodes that should be returned.