Java By Comparison

Favor Standalone Tests

class OxygenTankTest {
    OxygenTank tank;

    @BeforeEach
    void setUp() {
        tank = OxygenTank.withCapacity(10_000);
        tank.fill(5_000);
    }

    @Test
    void depressurizingEmptiesTank() {
        tank.depressurize();

        Assertions.assertTrue(tank.isEmpty());
    }

    @Test
    void completelyFillTankMustBeFull() {
        tank.fillUp();

        Assertions.assertTrue(tank.isFull());
    }
}

When we are teaching Java, we often see beginners who love to use the @BeforeEach and @BeforeAll annotations. After all, they allow you to extract common setup code that you need in the given part of a test and write it only once. That’s a good thing, because it avoids code duplication. But it comes at a price: setup methods make tests harder to ...