I have added tests with small numbers to test cases, big numbers to sample tests, and am now using the test framework for python.

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Random tests added for both Python and Java.

Resolved.

Why are random tests needed? And how would you even evaulate the correct answer for a random input?

I'm not sure at all what you mean in your first point. What fixed tests? What test cases??
All the tests in the test cases use big numbers.

I've resolved this.

Never seen " " used as a conditional before - is there any certain reason to use this?

Added and did some rewording too. Thanks!

Sorry should have mentioned this case in the Kata - 0 means no contribution to product so 10 would just be 1st prime => 2

I'm really struggling to understand how this works. I've stepped through it in a debugger and it still baffles me.