JUnit 5 Tutorial – @BeforeEach Annotation
This is a continuation of the JUnit 5 tutorial. The introduction is posted here.
annotation @BeforeEach
used to indicate that an annotated method should be executed before each method @Test, @RepeatedTest, @ParameterizedTest,
or @TestFactory
in the current class.
JUnit 5 annotation @BeforeEach is one of the lifecycle methods and replaces annotation @Before
in JUnit 4.
By default, test methods will execute on the same thread as annotated @BeforeEach
method.
1. Using @BeforeEach
@BeforeEach
public void initEach(){
//test setup code
}
@Test
void succeedingTest() {
//test code and assertions
}
@BeforeEach
public static void initEach(){
//test setup code
}
//Error
org.junit.platform.commons.JUnitException: @BeforeEach method 'public static void com.howtodoinjava.junit5.examples. JUnit5AnnotationsExample.initEach()' must not be static.
at org.junit.jupiter.engine.descriptor. LifecycleMethodUtils.assertNonStatic(LifecycleMethodUtils.java:73)
@BeforeEach in parent and child classes
Method
@BeforeEach
inherits from parent classes (or interfaces) as long as they are not hidden Or no redefined…In addition, each method annotated
@Before
from parent classes (or interfaces) will be executed front each method with annotation@Before
in child classes.
2. Example @BeforeEach
We used Calculator
class and added one method add()
…
Testing 5 times with annotation @RepeatedTest
… annotation @RepeatedTest
will cause the test to run add
() Five times.
Annotated @BeforeEach
the method must be executed each time the test method is called.
import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.BeforeAll;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.DisplayName;
import org.junit.jupiter.api.RepeatedTest;
import org.junit.jupiter.api.RepetitionInfo;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.TestInfo;
public class BeforeEachTest {
@DisplayName("Add operation test")
@RepeatedTest(5)
void addNumber(TestInfo testInfo, RepetitionInfo repetitionInfo) {
System.out.println("Running test -> " + repetitionInfo.getCurrentRepetition());
Assertions.assertEquals(2, Calculator.add(1, 1), "1 + 1 should equal 2");
}
@BeforeAll
public static void init(){
System.out.println("BeforeAll init() method called");
}
@BeforeEach
public void initEach(){
System.out.println("BeforeEach initEach() method called");
}
}
This is the calculator class:
public class Calculator
{
public int add(int a, int b) {
return a + b;
}
}
Now run the test and you will see the console output below:
ВыходBeforeAll init() method called
BeforeEach initEach() method called
BeforeEach initEach() method called
Running test -> 1
BeforeEach initEach() method called
Running test -> 2
BeforeEach initEach() method called
Running test -> 3
BeforeEach initEach() method called
Running test -> 4
BeforeEach initEach() method called
Running test -> 5
Obviously the annotated @BeforeEach
method initEach()
called once when calling the test method…
Have a nice study !!!