Nested tests for JUnit

Add the following dependencies to your pom.xml:

  <dependency>
    <groupId>net.avh4.test</groupId>
    <artifactId>junit-nested</artifactId>
    <version>1.0.1</version>
    <scope>test</scope>
  </dependency>

Now write nested tests as shown below. Your test class can have non-static inner classes, each of which may contain @Test methods. The inner classes themselves can also have inner classes, nested to any depth (though you may want to restructure your tests if you find yourself needing more than two levels). @Before and @After blocks at all levels will be executed as you would expect (for example, Outer-Before, Inner-Before, Test, Inner-After, Outer-After). @Rules at all levels will also be applied in the appropriate order.

import net.avh4.test.junit.Nested;

@RunWith(Nested.class)
public class QueueTest {
    private Queue<String> subject;

    @Before
    public void setUp() {
        subject = new Queue<String>();
    }

    @Test
    public void push_shouldIncreaseCount() {
        subject.push("Item");
        assertThat(subject.count(), is(1));
    }

    public class WhenEmpty {
        @Test(expected = NoSuchElementException.class)
        public void pop_shouldThrow() {
            subject.pop();
        }
    }

    public class WithOneItem {
        @Before
        public void setUp() {
            subject.push("First");
        }

        @Test
        public void pop_shouldReturnTheItem() {
            assertThat(subject.pop(), is("First"));
        }
    }
}

What works

• @Before methods at all levels
• @After methods at all levels
• @Rule fields at all levels
• @Test(expected) for expected exceptions
• @Test(timeout) for test timeouts
• @Ignore for pending tests

What doesn't work (yet)

• @BeforeClass methods for outer classes
• @AfterClass methods for outer classes
• @Rule methods (however, @Rule fields do work) for outer classes
• @RunWith on inner classes

License

junit-nested is licensed under the Eclipse Public License version 1.0. If you have need of a different license, please contact me.

References

Below are some resources I investigated before writing junit-nested, which offer some different approaches to behavioral testing in Java (and other languages).

• http://jdave.org/ - too different from JUnit
• http://www.malethan.com/article/rspec_for_java_jspec.html - blue sky
• http://igorpolevoy.blogspot.com/2011/04/what-good-for-ruby-is-good-for-java.html - nothing special
• http://www.easyb.org/specexmpls.html - requires groovy, plus external runner
  • http://www.javaworld.com/javaworld/jw-09-2008/jw-09-easyb.html
• http://www.videosurf.com/video/beyond-test-driven-development-behaviour-driven-development-103819366?vlt - to watch
• https://github.com/thoughtbot/shoulda-context - ruby
  • http://stackoverflow.com/questions/8740765/run-the-same-tests-in-various-context-with-shoulda-context-in-a-rails-app
• http://rspec.info/ - ruby