The present invention provides a method and system for providing a legal sequential combination of commands for verification testing of a computer system. Executable test commands are used to form sequentially ordered “buckets” of commands, wherein each bucket command sequence is legal under at least one rule. The buckets may be arranged in any sequential order, wherein a composite command sequence of the combined commands remains legal under the at least one rule. A further advantage of the invention is that wait/noop commands may be inserted within and between the buckets, extending the testing capabilities of the present invention into corner cases.