@BeforeAll method in JUnit - Build an Automation Script

Verify @BeforeAll method runs once before all tests

Preconditions (2)

Step 1: Create a test class with a static method annotated with @BeforeAll

Step 2: In the @BeforeAll method, set a static boolean flag to true

Step 3: Create two test methods that assert the static boolean flag is true

Step 4: Run the test class

✅ Expected Result: The @BeforeAll method runs once before any test method, so both test methods pass asserting the flag is true

Automation Requirements - JUnit 5

Assertions Needed:

Assert that the static boolean flag is true in each test method

Best Practices:

Use static method for @BeforeAll

Use assertions from org.junit.jupiter.api.Assertions

Keep @BeforeAll method simple and fast

Automated Solution

JUnit

import org.junit.jupiter.api.BeforeAll;
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.assertTrue;

public class BeforeAllExampleTest {
    private static boolean isSetupDone = false;

    @BeforeAll
    public static void setup() {
        isSetupDone = true;
    }

    @Test
    public void testOne() {
        assertTrue(isSetupDone, "Setup should be done before testOne");
    }

    @Test
    public void testTwo() {
        assertTrue(isSetupDone, "Setup should be done before testTwo");
    }
}

The @BeforeAll method setup() is static and runs once before any test method in the class.

It sets the static boolean isSetupDone to true.

Each test method asserts that isSetupDone is true, confirming the @BeforeAll method ran before tests.

This shows how @BeforeAll prepares shared setup for all tests.

Common Mistakes - 3 Pitfalls

Making the @BeforeAll method non-static

Putting heavy or slow operations in @BeforeAll

Not using assertions to verify setup effects

Bonus Challenge

Now add a @BeforeAll method that initializes a shared resource (like a List) and verify it is not null in multiple tests

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