Unit testing UI rules Unit test UI rules, such as harnesses and sections. Unit testing a harness After you create a harness rule, you can run the rule to test it in the context of the application you are developing. Specify a test page for the rule to use, provide sample data as the input, run the rule, and examine the results. Unit testing a section After you create a section rule, you can run the rule to test it in the context of the application you are developing. Specify a test page for the rule to use, provide sample data as the input, run the rule, and examine the results.