Test suite branch

[pitbull51067]

Description

I created a new test case and puzzle to check if the rule would work if the cells of the puzzle could actually be lit, meaning that there would be no contradiction. I made this rule because there was no test case where the cell could actually be lit. The test case works and so I think CannotLightACellContradictionRule works!

Closes #581

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Enhancement (improvement to an already existing feature)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

How Has This Been Tested?

It has three test cases now where it checks different scenarios of the rule.

Checklist:

• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation (if applicable)
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[charlestian23]

Seems to be a repeat of #674 , which I reverted since that was accidentally merged into master. This is the correct PR, so I'm going to merge it.