Run an initializer in the very beginning of `gradle test` for JUnit 4

Question

In our project, we have a lot of JUnit 4 tests, and they are executed from Gradle.

Now, we wanted to insert an initializer for the entire "gradle test" execution. The initializer is a class-loading tweak, so it should run just once in the very beginning.

I have looked into some:

• JUnit's RunListener
  • RunListener does not run on Gradle.
  • https://github.com/gradle/gradle/issues/1330
• Similar with junit-foundation
  • I was trying this, but it didn't work for unsure reasons yet.
    • It might be because of its complicated classloading structure.
  • Still worth going deeper into it.
• JUnit's RunWith
  • We need to specify all the test class names.
    • We already have a lot of test classes.
    • And, when we add a new test class, we have to add the test class there, too. We easily forget.
    • JUnit 4: Set up things in a test suite before tests are run (like a test's @BeforeClass method, just for a test suite)
  • We wanted all the test classed to be looked up automatically (like normal gradle test).
    • How do I Dynamically create a Test Suite in JUnit 4?
  • ClasspathSuite may help to auto-lookup test classes?
    • https://github.com/takari/takari-cpsuite
  • But, gradle tests --tests="..." would not work as intended.
• Static initializer in test classes, to run just once through the entire test run?
  • Need to add so many static {} blocks in so many existing tests?
  • Easily to forget, too.

Does anyone have any more ideas to solve this? (If we have a way in JUnit 5, we'll consider that.)