Prime factors kata

Prime factor kata

Although quite short, this kata is fascinating in the way it shows how ‘if’ statements become ‘while’ statements as the number of test cases increase.  It’s also a wonderful example of how algorithms sometimes become simpler as they become more general.
1. Write a class named “PrimeFactors” that has one method: generate. The generate method takes an integer argument and returns a List<Integer>. That list contains the prime factors of argument in numerical sequence.
2. Write test and code for argument = 1. Result should be empty list.
3. Write test and code for argument = 2. Result should be [2].
4. Write test and code for argument = 3. Result should be [3].
5. Write test and code for argument = 4. Result should be [2,2].
6. Write test and code for argument = 6. Result should be [2,3].
7. Write test and code for argument = 8. Result should be [2,2,2].
8. Write test and code for argument = 9. Result should be [3,3].