What's bdd4J ?

Bdd4J is a BDD (Behaviour Drivven Development) test runner for JUnit inspired on Machine.Specifications (MSpec). It means, that anywhere you can use JUnit, you can use bdd4J without any effort.

How can I install it?

Bdd4J is in central Maven repository, so all you have to do is to add following lines to your pom.xml

<dependencies>
	[...]
        <dependency>
            <groupId>com.github.onliner10</groupId>
            <artifactId>bdd4J</artifactId>
            <version>1.0</version>
        </dependency>
	[...]
</dependencies>

How can i use it?

All you have to do is to add simple annotation to your test class.

@RunWith(Bdd4J.class)

Of course, bdd4j requires also JUnit to work so ensure it is included in your project. Besides this, you have to have at least Java 8 to use bdd4J (because of lambdas).

Example test

@RunWith(Bdd4J.class) 
public class When_using_bdd4J {

Estabilish estabilishes_runs_first = () 
	-> createSomeMocksAndOtherStuff();

Because of_doing_some_stuff = () 
	-> sut.doStuff();

public class you_can_use_nested_classes {
	//You can create nested classes, too
    Estabilish first_nested_estabilish = 
		() -> createMocksEtc();
	
    It true_should_be_true = () 
		-> Assert.assertTrue(true);

	It same_strings_should_be_equal = () 
		-> Assert.assertEquals("same", "same");

    Cleanup first_nested_cleanup = 
		() -> cleanupSomeStuff();

}

Cleanup some_stuff = () -> {
		File file = new File("temp.tmp");
		file.delete();
	};

}

Delegate types

Estabilish

There are invoked first. This is the place when you can set up all the stuff for your test (like mocks)

Because

This is, where the Act part executes. You should do there all the actual stuff

It

This is where you assert. It is invoked after all preceding Estabilishes and Becauses

Cleanup

If your test needs some cleanup after work, you can define it here. It will be invoked after all the it's in Cleanups scope executes.