Testing

JUnit 5

The quickest way to learn is to look at the tests that are already written. Tests tend to look very similar, with quite a lot of duplicate code (yes, this time duplicate code is not so bad).

One important thing to keep in mind is that a unit test has to function entirely on it's own: any state that it builds up is destroyed when it finishes. Be careful with properties on the testclass, never count on them retaining their value from a previous test.

For a comprehensive guide, have a look here

Tip: add the following static import:

import static org.junit.jupiter.api.Assertions.*;

at the top of your test file, this will give you access to all the Junit assert methods.

Database Tests

To test your sql queries, make a test class that extends the DatabaseTest class. It provides you with a Jdbi instance that you can easily use within your tests. The instance is re-initialized before every test, so you can assume the database is empty at the start of every test.

Here's a quick example of a DAO test class:

// imports are omitted

class BatonDAOTest extends DatabaseTest {
    private BatonDAO batonDAO;

    @Override
    @BeforeEach
    public void setUp() throws Exception {
        // don't forget the super call when overriding the setUp method!!
        super.setUp();
        // make a batonDAO available for every test. Since this method is run before each test
        // we can be sure that it is valid.
        batonDAO = jdbi.onDemand(BatonDAO.class);
    }

    @Test
    void createBaton() {
        Baton testbaton = new Baton("testbaton");
        final Id testId = batonDAO.insert(testbaton);
        // there are no guarantees for the exact value of an auto-generated ID,
        // so we don't test for them
        assertTrue(testId.getId() > 0);

        Optional<Baton> batonOptional = batonDAO.findBatonById(testId.getId());
        assertFalse(batonOptional.isEmpty());
        Baton baton = batonOptional.get();
        // baton cannot be null here because of the previous assertion
        assertEquals("testbaton", baton.getName());
    }
}

Integration Tests