Determining code coverage of a computer program is disclosed. In an embodiment, the program is divided into a plurality of code sections, and the program including the plurality of code sections is run with a plurality of test data sets. In the first test run, all code sections of the plurality of code sections are instrumented, and in each of a current test run other than the first test run, only those code sections that were not executed in any one of the test runs prior to the current test run are instrumented. A code section being executed in any of one of the test runs of the plurality of test runs is considered covered by the test runs. Additionally, within the current test run, the code coverage measurement is only done on the first execution of a code section.