Provided are techniques for system testing using time compression.A first program and a second program of a workload are executed in accordance with a test clock, wherein the test clock is independent of a computer system clock, and wherein the first program and the second program are to be run in a specified sequence and each at a specified date and time. In response to the first program completing, the test clock is dynamically updated to the specified date and time of the second program to start execution of the second program.