Green
Red: it returns a list with 1 element if a = b - 1
Green
Refactor: introduce a variable to hold the SUT
Refactor: use one liners for test bodys
Refactor: move variable declaration scope
new test, but it does not force me to write production code
Remove test that didn't force to write new production code
Red: returns list which only element is the double of a when a == b - 1 and a is odd
Green
Red: returns list which only element is the double of b when a == b - 1 and a is even