Support @ParameterizedTest in conjunction with @TestFactory

[reitzmichnicht]

Overview

I started to write some dynamic tests, and now it would be handy to reuse some @ParameterizedTest functionality I already implemented.

Take a look at this example:

  @ParameterizedTest(name = "{0}")
  @ArgumentsSource(ClassArgumentsProvider.class)
  @TestFactory
  Stream<DynamicTest> apiGuards(Class<?> c) {
    return ApiGuardHelper.checkGuards(() -> EnhancedRandom.random(c));
  }

This should generate some dynamic tests for each class found in the package, but sadly the @ParameterizedTest annotation is not supported with a @TestFactory method.

Kind regards,
Michael

Related Issues

• Introduce extension API for container templates #871
• Introduce support for parameterized containers (classes, records, etc) #878

[sbrannen]

Why don't you just extract the logic from your ClassArgumentsProvider that generates the stream of classes and use that stream directly within your @TestFactory method to generate the Stream<DynamicTest> (instead of the Stream<Arguments> created in your provider)?

You could put that in a common utility and use the utility (e.g., static factory method) both from your provider as well as in test factories.

[sbrannen]

FWIW, it is not feasible for JUnit Jupiter to treat a single method as two containers simultaneously: it just doesn't make sense.

Note that a @ParameterizedTest and a @TestFactory are both technically containers as opposed to tests (in terms of org.junit.platform.engine.TestDescriptor.Type).

[sbrannen]

Relates to #871 and #878.

[sbrannen]

Assigned to 5.1 backlog for team discussion.

[sbrannen]

ApiGuardHelper

Is this related to the API Guardian project created by the JUnit 5 team?

[reitzmichnicht]

This is my junit5 implementation of guard assertions as described here:
https://madstt.dk/verify-your-guards-with-autofixture/

It takes all public methods of a class and checks if null arguments are safely handled. So it generates for each parameter of each method a dynamic test. Now I want combine this to get these tests generated for each class in the package. So I want nested Testcontainers like nested classes:
GuardTest
-- Class A
-- -- Method B Param1
-- Class C
...

Combining a TestFactory with ParametrizedTest was the most obvious for me.

[sbrannen]

I want nested Testcontainers like nested classes

We actually already have support for nested dynamic containers! 😉

In the Dynamic Test Examples section of the User Guide you'll find a test method named dynamicTestsWithContainers() which demonstrates this feature.

I think that will cover your needs, but please reply here to let us know in any case.

Cheers!

Sam

[sormuras]

Here, at ConsoleDetailsTests is another example of dynamic container usage which produces a tree like:

[reitzmichnicht]

When it is supported by code to have nested dynamic containers it should also be possible by annotation.
It's always better to have tests maintainable and understandable which is more given by annotations instead of creating dynamic containers in code.

[marcphilipp]

I'm closing this issue as "declined".

[prdoyle]

Re @sbrannen "Why don't you just extract the logic from your ClassArgumentsProvider" - because I'm already using it with other @Test methods, and I want to use the same set of arguments in a @TestFactory.