inconsistency between exercises 1 and 6

[marcinwasilewski]

The 1st exercise - separation of concerns - calls for moving 4 methods from vendingMachine.js to balanceManager.js. The official solution includes increaseBalance, decreaseBalance, getBalance and canAfford. However, in the exercise "Fix your teammate's mistakes", the test calls for function isValidAmount from the module balanceManager.js, which at the time would have not been separated from vendingMachine.js.

The solution for this issue would involve adding isValidAmount as a fifth method to the test cases of the SoC exercise as well as some amendments to that exercise description.

[idosius]

Also, the code presented in the solution is different than the code available, so the solution should be updated.