How to get an actual code coverage report in IntelliJ IDEA?

Question

I have a simple class called SomeClass:

public class SomeClass {

    public int value = 0;

    public void inc() {
        value++;
    }

    public void dec()
    {
        if (isBiggerThanFive()) value--;
        value--;
    }

    private boolean isBiggerThanFive() {
        return value > 5;
    }
}

And a test class called TheTest:

class TheTest {

    SomeClass t;

    @BeforeEach
    void setUp() {
        t = new SomeClass();
    }

    @Test
    public void whenNewTestIsCreated_ValueIsZero()
    {
        assertEquals(t.value, 0);
    }

    @Test
    public void whenIncIsCalledWithValueOfZero_ValueIsOne()
    {
        t.inc();
        assertEquals(t.value, 1);
    }

    @Test
    public void whenDecIsCalledWithValueOfZero_ValueIsNegativeOne()
    {
        t.dec();
        assertEquals(t.value, -1);
    }
}

Note how the function dec is structured and how the whole if condition and the statement are on the same line. In the test, this part of decrementing by 2 when the value is bigger that 5 isn't tested. So I assume that I should see in the coverage report that this part is not covered. But that's what I get:

When instead I let the statment be on it's own line, I get the correct results:

Even though the code is completely the same, I get different results based on just the structure of the code. How can I have an indication that a part of a line isn't covered when it's not acutally covered?

Ivo Mori · Accepted Answer · 2020-05-21T02:14:10.517

IntelliJ's test coverage runner has different run settings (for performance reasons). By default, the Sampling mode is used. This results in a code line coverage with negligible (execution) slow-down. Now, if you'd like to have an accurate collection of the branch coverage (such as if-statements) then you can use the Trace mode. Using the Trace mode you'll get the following test coverage.

This is further documented on IntelliJ's help website. See Configure code coverage options.

How to get an actual code coverage report in IntelliJ IDEA?

1 Answers1