ledoyen / junit5-junitparams

JUnitParams for JUnit5 Jupiter

JUnit5-JunitParams

JUnitParams for JUnit5 Jupiter.

Annotation @Test is ignored by the extension as JUnit5 Jupiter discovers it as a standalone test, whereas the @Parameters one ships with concurrent @TestTemplate.

Classic tests annotated with @Test only are discovered and run as usual.

Samples

@Parameters({
        "17, false",
        "22, true"})
public void isAdultAgeDirect(int age, boolean valid) throws Exception {
    assertThat(new Person(age).isAdult()).isEqualTo(valid);
}

@Test // annotation is ignored, method is only called twice as there is two set of parameters
@Parameters(method = "adultValues")
public void isAdultAgeDefinedMethod(int age, boolean valid) throws Exception {
    assertThat(new Person(age).isAdult()).isEqualTo(valid);
}

private Object[] adultValues() {
    return new Object[]{new Object[]{17, false}, new Object[]{22, true}};
}

@Parameters
public void isAdultAgeDefaultMethod(int age, boolean valid) throws Exception {
    assertThat(new Person(age).isAdult()).isEqualTo(valid);
}

@SuppressWarnings("unused")
private Object[] parametersForIsAdultAgeDefaultMethod() {
    return adultValues();
}

JUnit5 Jupiter current limitations

• There is no proper way to retrieve the type of test from the ExtensionContext (isContainer, isTemplate)

  • JUnitParamsExtension extension currently use breakable internal class comparison

  private static Class<?> TEMPLATE_CONTEXT_CLASS =
    ReflectionUtils.loadClass(
        "org.junit.jupiter.engine.descriptor.TestTemplateContainerExtensionContext").get();
  
  boolean parentContextIsTemplateOne = TEMPLATE_CONTEXT_CLASS.equals(context.getParent().get().getClass());

  This is breakable as internal class are package-protected, and are not intended to be use from outside the framework

• It is not possible to invoke non-static methods on the test instance from extensions

  • As JUnit5 Jupiter supports constructor parameter injection, all extensions except TestInstancePostProcessor run before test class instantiation
  • JUnitParamsExtension extension currently use breakable test class instantiation with default JUnit5 extensions (see ExtensionRegistry#DEFAULT_EXTENSIONS)

  Constructor<?> constructor = ReflectionUtils.getDeclaredConstructor(testClass);
  Object instance = executableInvoker
    .invoke(constructor,
            extensionContext,
            ExtensionRegistry.createRegistryWithDefaultExtensions(new EmptyConfigurationParameters()));

  This is breakable as both explicit and registered (by ServiceLoader mechanism) extensions cannot be used for constructor parameter injection for classes containing @Parameters tests.