Please change the following things:

• add <?php to solution and solution setup. Currently it only works without because of backwards compatiblity
• add assertion failure messages showing the input to all tests (sample/full)
• add sample tests as fixed tests to full test suite
• rename full tests class to something like SolutionTest
• adjust random tests to create longer inputs (e.g. rand(50))
• random tests should draw random letters from the alphabet to also include the same letter multiple times

You're right. Thanks for letting me know! Corrected.

@crossbred, I think you changed the function name in the tests but missed updating it in the Solution Setup.

Great! I will do that. Thanks!

Solved the problem.

Added random tests.

Added random tests.

Failed asserting that 'Player2' matches expected null.
Expected: null
Actual  : Player2

covering cases with fixed tests is good. nonetheless, you will still have to implement random tests. they are not optional.

no random tests

Added three rounds of the game, showing two, three and four fingers.
There is no chance to tie; since, if one player chooses even the other it is up to him odd and vice versa.
Simplified the player class.

I have considered all possible cases, so I consider random tests unnecessary.

Added sample tests.