Your tests, checked
Coverage says a line ran. mutastic changes that line, >= to > say, and runs the tests that
reach it. If they all still pass, nothing checks what the line does.
mutastic
Mutation testing for Java. It changes your code in small ways, checks that your tests notice, and when they don't, tells you the test to write.
The test to write
Each missed mutant comes with the inputs your tests used, the gap they left, a test that would close it, and the command that proves it closed.
Three ways to run it
The mutastic command, mvn mutastic:run, or ./gradlew mutasticRun. The same run, the same
results, the same options.
Made for agents too
--format=agent gives coding agents the verdict first, then each gap and the rule that a fix
changes tests, never production code.