In JUnit 5, how to run code before all tests

Question

The @BeforeAll notes a method that runs before all tests in a class.

http://junit.org/junit5/docs/current/user-guide/#writing-tests-annotations

But is there a way to run some code before all tests in all classes?

I want to make sure that the tests use a specific set of database connections, and before performing any tests, global one-time setup of these connections must occur.

Answer 1

This is currently not supported, but for JUnit 5 there is a transfer request for this topic: Implement support before / after callbacks once for the entire test run .

Answer 2

This is now possible in JUnit5 by creating a custom extension from which you can register a shutdown hook in the root test context.

Your extension will look like this;

 import org.junit.jupiter.api.extension.BeforeAllCallback; import org.junit.jupiter.api.extension.ExtensionContext; import static org.junit.jupiter.api.extension.ExtensionContext.Namespace.GLOBAL; public class YourExtension implements BeforeAllCallback, ExtensionContext.Store.CloseableResource { private static boolean started = false; @Override public void beforeAll(ExtensionContext context) { if (!started) { started = true; // Your "before all tests" startup logic goes here // The following line registers a callback hook when the root test context is shut down context.getRoot().getStore(GLOBAL).put("any unique name", this); } } @Override public void close() { // Your "after all tests" logic goes here } } 

Then, any test classes where it is necessary to run at least once can be marked with:

 @ExtendWith({YourExtension.class}) 

When you use this extension for multiple classes, the start and end logic will be called only once.

Answer 3

You can mark each of your test classes that use your database with an interface that defines static BeforeAll (so that it cannot be overridden). eg:.

 interface UsesDatabase { @BeforeAll static void initializeDatabaseConnections() { // initialize database connections } } 

This method will be called once for each implementation class, so you will need to determine how to initialize your connections only once, and then do nothing for other calls.

Answer 4

I do not know how to do that.

I would just make sure all the code for @BeforeAll calls a specific singleton to make it work (perhaps in a lazy way to avoid repetition).

This is probably not convenient ... the only other option I can see: I assume that your tests are performed as part of the specific work of the JVM. You can connect agent to this JVM run that runs this init for you.

Also: both sentences sound like a hack to me. The real answer is in my eyes: step back and carefully examine your environment on its dependencies. And then find a way to prepare your environment so that your tests appear and the “right thing” happens automatically. In other words: consider the architecture that bought you this problem.

Answer 5

@Before and @After not supported in JUnit5, and now we have @BeforeEach and @AfterEach to maintain the same functionality from Junit 4.

From the Documentation:

@AfterEach : indicates that the annotated method should be executed after each @Test , @RepeatedTest , @ParameterizedTest or @TestFactory in the current class; similar to JUnit 4s @After . Such methods are inherited if they are not overridden.

 @AfterEach public void initCafe() { System.out.println("Test Completed"); } 

@BeforeEach : indicates that the annotated method must be executed before each @Test , @RepeatedTest , @ParameterizedTest or @TestFactory in the current class; similar to JUnit 4s @Before . Such methods are inherited if they are not overridden.

 @BeforeEach public void initCafe() { cafe = new Cafe(); } 

Read more about annotations here .