Either I have done something wrong, or there is something wrong with the test.

the array for first_moves = 25, 10, 10.

the array for second_moves = 5, 20, 10.

assertEquals(80, result[0]);

first player wins the first bid, so 100 - 25 = 75. the first player loses the second bid, but wins the third bid because the first player holds the draw. therefore, 75 - 10 should equal 65, not 80, as presented in the assertEquals.

Right? 

Yes, that's right, so change the assertEquals accordingly to what you said the expected value should be.

Remember that the player variable at this test case is 2, not 1. Therefore result[0] should be second player's money. In other word, the test case expected result is correct.