@BeforeAll method in JUnit - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the @BeforeAll method in JUnit?

The @BeforeAll method runs once before all test methods in a test class. It is used to set up shared resources or configurations needed for all tests.

beginner

When is the @BeforeAll method executed in the test lifecycle?

It is executed exactly one time before any test methods run in the test class.

intermediate

What must be true about a @BeforeAll method in JUnit 5 regarding its declaration?

The <code>@BeforeAll</code> method must be static unless the test class is annotated with <code>@TestInstance(TestInstance.Lifecycle.PER_CLASS)</code>.

beginner

Example: How do you write a @BeforeAll method to initialize a database connection?

Example:<br>

  @BeforeAll
  static void setup() {
    database.connect();
  }

intermediate

Why should you avoid putting test assertions inside a @BeforeAll method?

Because @BeforeAll is for setup only. Assertions belong in test methods to clearly show which test failed.

What is true about a @BeforeAll method in JUnit 5 by default?

A It must be static.

B It runs before each test method.

C It can only be private.

D It runs after all tests.

By default, @BeforeAll methods must be static because they run once before all tests.

Which annotation allows @BeforeAll methods to be non-static?

A @TestInstance(Lifecycle.PER_CLASS)

B @BeforeEach

C @AfterAll

D @Test

Using @TestInstance(Lifecycle.PER_CLASS) lets @BeforeAll methods be instance methods (non-static).

How many times does a @BeforeAll method run in a test class?

A Never

B Before each test

C After each test

D Once before all tests

@BeforeAll runs exactly once before any tests in the class.

Where should you put code that needs to run before every test method?

A @BeforeAll method

B @AfterAll method

C @BeforeEach method

D Inside the test method

@BeforeEach runs before every test method, unlike @BeforeAll.

Which of these is a good use case for @BeforeAll?

A Checking test results

B Opening a database connection once for all tests

C Resetting test data before each test

D Cleaning up after tests

@BeforeAll is ideal for one-time setup like opening a database connection.

Explain the role and requirements of the @BeforeAll method in JUnit testing.

Think about when and how often setup code should run.

Describe a scenario where using @BeforeAll is better than @BeforeEach.

Consider efficiency and resource sharing.