Reverting changes to other steps, concentrating on writing correct code for the 1st Core scenario to pass
1st scenario passing like it should
Second scenario in the core feature passing with real code.
Refactored mappings
Pending scenario passing
Undefined scenario passing
failed output scenario passing
Passing 1st calculator scenario
7 passing scenarios for Core, with real code. 5 failing
7 passing scenarios but now need to get parameters out of the regex to pass to the function