Input validation. No random tests. No tests with centuries.

Really ?!?

If the year is not a valid integer

Test.assertEquals(calucateSavings(1.5000), '£664.30');

So 1.5000 is a valid integer?

Needs random tests

Please add test cases [JavaScript]

this doesn't work but it should work
function multiplyBy(x, y, n) {
return Array.from(Array(n)).map((e, i) => {return x * y * Math.pow(y, i)});

};

more test and rendom ones +1

No tests

I think this kata need more tests.

Needs random test cases

I think we need some more testing examples.

Add Test

Running the tests didn't work but when I submitted it the solution was correct

Maybe few additional examples and tests would be good

put example answers into repl.it and it produced the correct solution but did not produce correct solution when put into this website's interpreter

Need test cases.