CodeSOD: Cover Up

Goodhart's Law states that, when a measure becomes a target, it ceases to be a good measure. Or, more to the point: you get what you measure.

If, for example, you measure code coverage, you are going to get code coverage. It doesn't mean the tests will be any good, it just means that you'll write tests that exercise different blocks of code.

For example, Capybara James sends us this unit test:

@MockitoSettings
class CentralizedLoggerTest {
    @InjectMocks
    private CentralizedLogger centralizedLogger;
    @Test
    void logAround() throws Throwable {
        centralizedLogger = new CentralizedLogger();
        MethodSignature signature = mock(MethodSignature.class);
        ProceedingJoinPoint joinPoint = mock(ProceedingJoinPoint.class);
        when(joinPoint.getSignature()).thenReturn(signature);
        centralizedLogger.logAround(joinPoint);
        Assertions.assertTrue(true);
    }
}

It doesn't really matter what the mocks are, or what gets instantiated, or honestly, anything that's happening here. The assertion is the beginning and ending.

James writes:

The only requirement was sonar coverage to push the code to production. There is no other purpose.

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This post originally appeared on The Daily WTF.