Custom display names for parameters in JUnit

Introduction

Custom display names make test results easier to read by showing meaningful names for test parameters instead of default values.

When you want test reports to clearly show what each test case is checking.

When parameter values are complex or unclear and need explanation.

When sharing test results with non-technical team members who need easy-to-understand reports.

When debugging tests and you want to quickly identify which input caused a failure.

Syntax

JUnit

@ParameterizedTest(name = "Test with fruit: {0}")
@ValueSource(strings = {"apple", "banana"})
void testWithCustomName(String fruit) {
    // test code
}

Use @ParameterizedTest(name = "...") to customize test names.

In JUnit 5, {0} refers to the first parameter value in the display name.

Examples

This test shows each animal name in the test report.

JUnit

@ParameterizedTest(name = "Animal test: {0}")
@ValueSource(strings = {"cat", "dog"})
void testAnimals(String animal) {
    assertNotNull(animal);
}

Using the name attribute in @ParameterizedTest to customize display names with index and parameter.

JUnit

@ParameterizedTest(name = "Run {index}: fruit={0}")
@ValueSource(strings = {"apple", "orange"})
void testFruits(String fruit) {
    assertTrue(fruit.length() > 0);
}

Sample Program

This test runs three times with different fruit names. The test report will show names like "Test fruit: apple" for clarity.

JUnit

import static org.junit.jupiter.api.Assertions.*;
import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.ValueSource;

class FruitTest {

    @ParameterizedTest(name = "Test fruit: {0}")
    @ValueSource(strings = {"apple", "banana", "cherry"})
    void testFruitNames(String fruit) {
        assertNotNull(fruit);
        assertTrue(fruit.length() > 0);
    }
}

Important Notes

Custom display names improve test report readability and help quickly identify failing cases.

Use {index} to show the test run number in the display name.

Always keep display names short and clear for best results.

Summary

Custom display names make test results easier to understand.

Use @ParameterizedTest(name = "...") or @DisplayName to set names.

Display names can include parameter values and test indexes.