@BeforeEach and @AfterEach
- Java course
- Advanced
- Lesson 45/82
- 5 min
Learn setup with @BeforeEach and @AfterEach.
@BeforeEach and @AfterEach
Code that should run before each test method is marked with @BeforeEach; code that runs after each test is marked with @AfterEach. These methods handle common setup and cleanup.
import org.junit.jupiter.api.*;
class CartTest {
List<String> cart;
@BeforeEach
void setup() { cart = new ArrayList<>(); }
@AfterEach
void cleanup() { cart.clear(); }
}Each test now runs independently; side effects from the previous test do not leak. Setup lives in one place and is not repeated. This keeps tests fast and reliable.
Class-level setup with @BeforeAll
For heavy resources (database connection, file) opened once, use @BeforeAll. This method must be static; the framework calls it once per class.
@BeforeAll
static void openDatabase() {
// connection opened once
}
@AfterAll
static void closeDatabase() {
// connection closed once
}This shortens test time. But make sure tests do not depend on each other; otherwise errors appear when order changes. @BeforeEach is usually preferred.
Practice Use @BeforeEach in a cart test
Write a CartTest class. Declare a List<String> cart field. In a @BeforeEach method setup, do cart = new ArrayList<>(). Write a @Test method testAdd that calls cart.add("apple") and verifies with assertEquals(1, cart.size()). Add a main method, add one item and print size().
Starter code
import org.junit.jupiter.api.*;
import java.util.*;
// Define the CartTest class
// cart field, setup annotation with setup, test annotation with testAdd
// Add a main method that prints cart.size()Sample solution
import org.junit.jupiter.api.*;
import java.util.*;
class CartTest {
List<String> cart;
@BeforeEach
void setup() {
cart = new ArrayList<>();
}
@Test
void testAdd() {
cart.add("apple");
assertEquals(1, cart.size());
}
public static void main(String[] args) {
CartTest t = new CartTest();
t.setup();
t.cart.add("apple");
System.out.println(t.cart.size());
}
}Expected output
1
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 Match lifecycle annotations
| Term | Meaning |
|---|---|
@BeforeEach |
Before each test |
@AfterEach |
After each test |
@BeforeAll |
Before the class (static) |
@AfterAll |
After the class (static) |
2 Complete the BeforeAll method
@BeforeAll
____ void openResource() {
// tek seferlik kurulum
}@BeforeAll
static void openResource() {
// tek seferlik kurulum
}Explanation: @BeforeAll methods must be static.
3 What is the difference between @BeforeEach and @BeforeAll?
- BeforeEach runs before each test, BeforeAll before the class Correct answer
- BeforeAll runs before each test, BeforeEach before the class
- They are the same, only the names differ
- BeforeAll runs only on error
Explanation: BeforeEach runs before each test, BeforeAll once before the class.