JUnit – About (original) (raw)

JUnit is a simple framework to write repeatable tests. It is an instance of the xUnit architecture for unit testing frameworks.

JUnit 5

@Test
public void newArrayListsHaveNoElements() {
    assertThat(new ArrayList<Integer>().size(), is(0));
}

@Test
public void sizeReturnsNumberOfElements() {
    List<Object> instance = new ArrayList<Object>();
    instance.add(new Object());
    instance.add(new Object());
    assertThat(instance.size(), is(2));
}

Annotations

Start by marking your tests with @Test.

@Test
public void lookupEmailAddresses() {
    assertThat(new CartoonCharacterEmailLookupService().getResults("looney"), allOf(
        not(empty()),
        containsInAnyOrder(
            allOf(instanceOf(Map.class), hasEntry("id", "56"), hasEntry("email", "[[email protected]](/cdn-cgi/l/email-protection)")),
            allOf(instanceOf(Map.class), hasEntry("id", "76"), hasEntry("email", "[[email protected]](/cdn-cgi/l/email-protection)"))
        )
    ));
}

Hamcrest matchers

Make your assertions more expressive and get better failure reports in return.

‹ ›

Welcome

Usage and Idioms

Third-party extensions