This is a good example of a method that works fine, but is not very testable the way it's written (writing testable code can be surprisingly difficult!). An alternative would be to have `blankToMine` accept a row and column as parameters, which you can then generate with the same call to `Math.random()` wherever you're invoking `blankToMine`. The reason for this is that you can then call `blankToMine` with a set of known inputs in your test, and assert that that square is set to an `'X'` afterwards!