CODEWITHSUNDEEP
javajunitjunit5junit5-extension-model
Baptiste Le Bail
Baptiste Le Bail

Reputation: 145

What is the equivalent of @RuleChain in JUnit 5?

In JUnit 4, it can be implemented this way, via the RuleChain :

static MyRule1 myRule1 = new MyRule1();
static MyRule2 myRule2 = new MyRule2(myRule1);

@Rule
TestRule ruleChain = RuleChain.outerRule(myRule1)
        .around(myRule2);

In JUnit 5, I have to implement it this way :

static MyRule1 myRule1 = new MyRule1();

@RegisterExtension
static MyRule2 myRule2 = new MyRule2(myRule1);

with MyRule2 :

class MyRule2 implements BeforeAllCallback {

    private final MyRule1 myRule1;

    public MyRule2(MyRule1 myRule1) {
        this.myRule1 = myRule1;
    }

    @Override
    public void beforeAll(ExtensionContext extensionContext) {
        this.myRule1.beforeAll();

        X x = this.myRule1.getX();
        // do Rule 2 stuff with x
    }
}

It's the equivalent of the JUnit 4 implementation when it comes to the result.

But I have to explicitly and manually call the beforeAll() callback of MyRule1 in MyRule2.

I would like that MyRule2 would not be responsible for MyRule1 execution.

I went through the Extension Model documentation of JUnit 5 but didn't find anything on extensions that depend on other extensions.

Upvotes: 10

Views: 2890

Answers (3)

Marthym
Marthym

Reputation: 3219

For extensions registered via @RegisterExtension, some libraries as testy-box provide a support for Chained Extensions.

Upvotes: 0

Sam Brannen
Sam Brannen

Reputation: 31247

For extensions registered via @RegisterExtension, there is currently (as of JUnit Jupiter 5.3.1) no built-in support analogous to JUnit 4's RuleChain.

However, this issue links to a custom solution and also proposes support for @Order to control the order in which extensions are executed.

Upvotes: 1

Mureinik
Mureinik

Reputation: 311823

To quote Jupiter's documentation:

Extensions registered declaratively via @ExtendWith will be executed in the order in which they are declared in the source code.

So, in your case, you should just declare them in that order:

@ExtendsWith({Rule1.class, Rule2.class})
public class MyTest {

Upvotes: 2

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