You need to check argument rank in incProgress(int rank), if rank == 0, > 8 or < -8 throw IllegalArgumentException

if (< condition >) throw new IllegalArgumentException("Optional message");

actually when i run my code the sample test is all right,
but when i attempt it ,it gives me differnt types of error on same code.

Thanks for reporting, I guess...

Broken how?

this kata is broken!

how to throw exception in this kata in java?
Expected exception: java.lang.Exception

Spoiler...?

Same here.
Its more of a mathmatical question rather than complex algrithoms

all my random test are going correct except factorial of 15