JUnit 5 Display Names

In JUnit 5, we can use @DisplayName to declare custom display names for test classes and test methods.

P.S Tested with JUnit 5.5.2

1. @DisplayName

1.1 Default name of test classes and methods.

DisplayNameTest.java

package com.mkyong.display;

import org.junit.jupiter.api.Test;

public class DisplayNameTest {

    @Test
    void test_spaces_ok() {
    }

    @Test
    void test_spaces_fail() {
    }

}

Output

output

+-- JUnit Jupiter [OK]
| '-- DisplayNameTest [OK]
|   +-- test_spaces_ok() [OK]
|   '-- test_spaces_fail() [OK]

1.2 @DisplayName

DisplayNameCustomTest.java

package com.mkyong.display;

import org.junit.jupiter.api.DisplayName;
import org.junit.jupiter.api.Test;

@DisplayName("I'm a Test Class")
public class DisplayNameCustomTest {

    @Test
    @DisplayName("Test with spaces, expected ok")
    void test_spaces_ok() {
    }

    @DisplayName("Test with spaces, expected failed")
    @Test
    void test_spaces_fail() {
    }

}

Output

output

+-- JUnit Jupiter [OK]
| '-- I'm a Test Class [OK]
|   +-- Test with spaces, expected ok [OK]
|   '-- Test with spaces, expected failed [OK]

2. Display Name Generators

2.1 We can also create a custom display name generator and configured via the @DisplayNameGeneration.

2.2 This example uses the JUnit ReplaceUnderscores generator to replace the underscores with spaces.

DisplayNameGenerator1Test.java

package com.mkyong.display;

import org.junit.jupiter.api.DisplayNameGeneration;
import org.junit.jupiter.api.DisplayNameGenerator;
import org.junit.jupiter.api.Test;

import java.lang.reflect.Method;

@DisplayNameGeneration(DisplayNameGenerator.ReplaceUnderscores.class)
public class DisplayNameGenerator1Test {

    @Test
    void test_spaces_ok() {
    }

    @Test
    void test_spaces_fail() {
    }

}

Output

output

2.3 We can extend the JUnit DisplayNameGenerator to create our custom display name generator.

DisplayNameGenerator2Test.java

package com.mkyong.display;

import org.junit.jupiter.api.DisplayNameGeneration;
import org.junit.jupiter.api.DisplayNameGenerator;
import org.junit.jupiter.api.Test;

import java.lang.reflect.Method;
import java.util.Arrays;
import java.util.stream.Collectors;

@DisplayNameGeneration(DisplayNameGenerator2Test.CustomDisplayNameGenerator.class)
public class DisplayNameGenerator2Test {

    @Test
    void test_spaces_ok() {
    }

    @Test
    void test_spaces_fail() {
    }

    static class CustomDisplayNameGenerator extends DisplayNameGenerator.Standard {

        @Override
        public String generateDisplayNameForClass(Class<?> testClass) {
            return "New Name for test class";
        }

        @Override
        public String generateDisplayNameForNestedClass(Class<?> nestedClass) {
            return super.generateDisplayNameForNestedClass(nestedClass);
        }
        
        @Override
        public String generateDisplayNameForMethod(Class<?> testClass, Method testMethod) {
            String name = testMethod.getName();
            return Arrays.stream(name.split("_")).collect(Collectors.joining(" | "));
        }
    }

}

Output

output

3. Parameterized Tests

3.1 For parameterized tests, we can declare the custom display name via the name attribute of the @ParameterizedTest, see the following example:

DisplayNameParamTest.java

package com.mkyong.display;

import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.Arguments;
import org.junit.jupiter.params.provider.EnumSource;
import org.junit.jupiter.params.provider.MethodSource;

import java.util.concurrent.TimeUnit;
import java.util.stream.Stream;

import static org.junit.jupiter.params.provider.Arguments.arguments;

public class DisplayNameParamTest {

    @ParameterizedTest(name = "#{index} - Test with TimeUnit: {0}")
    @EnumSource(value = TimeUnit.class, names = {"MINUTES", "SECONDS"})
    void test_timeunit_ok(TimeUnit time) {
    }


    @ParameterizedTest(name = "#{index} - Test with {0} and {1}")
    @MethodSource("argumentProvider")
    void test_method_multi(String str, int length) {
    }

    static Stream<Arguments> argumentProvider() {
        return Stream.of(
                arguments("abc", 3),
                arguments("lemon", 2)
        );
    }

}

Output

output

Download Source Code

$ git clone https://github.com/mkyong/junit-examples
$ cd junit5-examples
$ check src/test/java/com/mkyong/display/*.java

References

About the Author

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mkyong
Founder of Mkyong.com, love Java and open source stuff. Follow him on Twitter. If you like my tutorials, consider make a donation to these charities.

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