This article contains a JUnit 5 Cheatsheet which you can use as handy reference to build your JUnit 5 Jupiter Tests in Java.
Maven Dependencies:
Here is the list of dependencies you have to include in your pom.xml according to the latest JUnit version (April 2024):
<dependencies>
<dependency>
<groupId>org.junit.jupiter</groupId>
<artifactId>junit-jupiter-api</artifactId>
<version>5.10.2</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.junit.jupiter</groupId>
<artifactId>junit-jupiter-engine</artifactId>
<version>5.10.2</version>
<scope>test</scope>
</dependency>
</dependencies>
Gradle dependencies
Include in your build.gradle the following dependencies:
dependencies {
testImplementation('org.junit.jupiter:junit-jupiter-api:5.10.2')
testRuntime('org.junit.jupiter:junit-jupiter-engine:5.10.2')
}
Basic JUnit 5Test
import static org.junit.jupiter.api.Assertions.assertEquals;
import org.junit.jupiter.api.Test;
public class JUnit5ExampleTest {
@Test
void firstTest() {
assertEquals("ok","ok");
}
}
Lifecycle:
Callback methods that will run according to Test lifecycle:
import org.junit.jupiter.api.*;
public class AppTest {
@BeforeAll
static void setup(){
System.out.println("Executes a method Before all tests");
}
@BeforeEach
void setupThis(){
System.out.println("Executed Before each @Test method in the current test class");
}
@AfterEach
void tearThis(){
System.out.println("Executed After each @Test method in the current test class");
}
@AfterAll
static void tear(){
System.out.println("Executes a method After all tests");
}
}
Assertions
Assertions help in validating the expected output with the actual output of a test.
@Test
void exampleTest() {
Assertions.assertTrue(trueBool);
Assertions.assertFalse(falseBool);
Assertions.assertNotNull(notNullString);
Assertions.assertNull(notNullString);
Assertions.assertNotSame(originalObject, otherObject);
Assertions.assertEquals(4, 4);
Assertions.assertNotEquals(3, 2);
Assertions.assertArrayEquals(new int[]{1,2,3}, new int[]{1,2,3}, "Array Equal Test");
Iterable<Integer> listOne = new ArrayList<>(Arrays.asList(1,2,3,4));
Iterable<Integer> listTwo = new ArrayList<>(Arrays.asList(1,2,3,4));
Assertions.assertIterableEquals(listOne, listTwo);
Assertions.assertTimeout(Duration.ofMillis(100), () -> {
Thread.sleep(50);
return "result";
});
Throwable exception = Assertions.assertThrows(IllegalArgumentException.class, () -> {
throw new IllegalArgumentException("error message");
});
Assertions.fail("not found good reason to pass");
}
Assumptions
A failed assumption results in a test being aborted because it does not make sense to continue execution of a given test method.
@Test
void testAssumption() {
System.setProperty("myproperty", "foo");
Assumptions.assumeTrue("foo".equals(System.getProperty("myproperty")));
}
@Test
public void testConnection() {
boolean isConnected = checkConnection(); // Some method that checks the network connection
assumingThat(isConnected, () -> {
// Test code that requires an active network connection
// e.g. test to check the API call
assertTrue(myApiCall().contains("Hello World"));
});
}
Conditional Execution
Your Test will be executed according to a set of different conditions available in org.junit.jupiter.api.condition package.
JRE Conditional Execution
Conditional execution based on JRE that you are using to start the Test.
public class AppTest
{
@Test
@EnabledForJreRange(min = JRE.JAVA_8, max = JRE.JAVA_11)
public void test1()
{
System.out.println("Will run only on JRE between 8 and 11");
}
@Test
@EnabledOnJre({JRE.JAVA_8, JRE.JAVA_11})
public void test2()
{
System.out.println("Will run only on JRE 8 and 11");
}
@Test
@DisabledForJreRange(min = JRE.JAVA_8, max = JRE.JAVA_11)
public void test3()
{
System.out.println("Will NOT run on JRE between 8 and 11");
}
@Test
@DisabledOnJre({JRE.JAVA_8, JRE.JAVA_11})
public void test4()
{
System.out.println("Will NOT run on JRE 8 and 11");
}
}
Operating System Conditional Execution
public class OperatingSystemTest {
@Test
@EnabledOnOs({OS.LINUX, OS.WINDOWS})
void onLinuxOrWindows() {
System.out.println("Will run on Linux or Windows.");
}
@Test
@DisabledOnOs({OS.WINDOWS, OS.AIX, OS.SOLARIS, OS.MAC})
void notOnWindowsOrAixOrSolarisOrMac() {
System.out.println("Will not run on Windows, AIX, Solaris or MAC!");
}
}
Method return value Conditional Execution
@Test
@EnabledIf("myfunction")
void enabled() {
assertTrue(true);
}
@Test
@DisabledIf("myfunction")
void disabled() {
assertTrue(true);
}
boolean myfunction() {
return true;
}
Env variable and System Property Conditional Execution
@Test
@EnabledIfEnvironmentVariable(named = "ENV", matches = ".*oracle.*")
public void executeOnlyInDevEnvironment() {
return true;
}
@Test
@DisabledIfEnvironmentVariable(named = "ENV", matches = ".*mysql.*")
public void disabledOnProdEnvironment() {
return true;
}
@Test
@EnabledIfSystemProperty(named = "my.property", matches = "prod*")
public void onlyIfMyPropertyStartsWithProd() {
return true;
}
Repeated jUnit Tests
The @RepeatedTest annotation enable to run multiple times single tests in JUnit 5. The number of times the test will be executed can be configured as parameter to @RepeatedTest annotation.
@Test
@RepeatedTest(5)
void addNumber() {
Calculator calculator = new Calculator();
Random rand = new Random();
int n = rand.nextInt(50);
Assertions.assertEquals(n*2, calculator.add(n, n), "Checking calculator sum");
}
Testsuite
Using JUnit 5 test suites, you can run tests spread into multiple test classes and different packages:
@RunWith(JUnitPlatform.class)
@SelectPackages("com.howtodoinjava.junit5.examples.packageA")
public class JUnit5TestSuiteExample
{
}
Conclusion
JUnit 5 cheatsheet was provided by Mastertheboss.com. Check the list of our CheatSheets.
