How to Customize Display Names for @ParameterizedTest in JUnit 5?

How can I customize the display names for @ParameterizedTest in JUnit 5, especially when dealing with complex parameter types?

@ParameterizedTest
@MethodSource("provideTestParameters")
void testMethod(WebDriver driver) {
    // test implementation
}

In JUnit 5, customizing the display names of parameterized tests can enhance readability, especially when dealing with complex objects. By default, display names include the invocation index and the parameters' string representations, which can be verbose. To better control these display names, we can employ several customization strategies.

@ParameterizedTest(name = "Test with driver: {0}")
@MethodSource("provideTestParameters")
void testMethod(WebDriver driver) {
    // test implementation
}

Causes

• The default behavior of @ParameterizedTest includes verbose toString() output from the parameters, which can lead to unclear test names.
• The @DisplayNameGeneration annotation is class-level and does not apply individually to parameterized test invocations.

Solutions

• Use the 'name' attribute of @ParameterizedTest to customize individual test invocation display names directly.
• Create a method that formats display names based on the parameters being passed, and use it in conjunction with the 'name' attribute.
• Consider implementing a custom DisplayNameGenerator that suits your needs and targeting the specific structure of the parameters.

Mistake: Not using the 'name' attribute, leading to confusing and verbose display names.

Solution: Always specify the 'name' attribute with a meaningful format, e.g., @ParameterizedTest(name = "Test with: {0}").

Mistake: Assuming that @DisplayNameGeneration affects parameterized tests.

Solution: Remember that @DisplayNameGeneration applies to the class level; use 'name' to directly customize individual test display names.