Precondition: - one valid set in pool Steps: 1. player have 3 tiles in rack which form a invalid set (e.g. 10 Yellow, 11 Yellow, 11 Yellow) 2. add the invalid tile to pool 3. end the round Expected: - invalid move, draw a tile Actual: - invalid move, backup has done, but not draw a tile JUnit test: test_round_optionSwitch_24() Related bug: 214