to dear mod,
I want to recommend from now on if someone want to take retest have to pay 100 DP, also if someone joke around in the test should receive penalty.
here is the penalty i recommend:
first time: 1 month cannot take retest
second time: 3 month cannot take retest
third time: 6 month cannot take retest, the amount of DP require to take test become 1000
fouth time:1 year cannot take retest and the amount of DP require to take test become 3000
fifth time: permanently cannot take retest until the mod allow it