The order of faults which are targeted for test-pattern generation affects both of the processing time for test generation and the number of generated test-patterns. This order is referred to as a test generation schedule. In this paper, we consider the effect of scheduling in test generation. We formulate the test generation scheduling problem which minimizes the cost of testing. We propose schedulings based on test-pattern generation time, dominating probability and dominated probability, and analyze the effect of these schedulings. In the analysis, we show that the total test-pattern generation time and the total number of test-patterns can be reduced by the scheduling according to the descending order of dominating probability prior to the ascending order of test-pattern generation. This is confirmed by the experiments using ISCAS'85 benchmark circuits. Further, in the experiments, we consider eight schedulings, and show that the scheduling according to the ascending order of dominated probability is the most effective of them.