Dataflow tests

[wmdietl]

When looking through the CI log, I notice:

> Task :dataflow:test
The automatic loading of test framework implementation dependencies has been deprecated. This is scheduled to be removed in Gradle 9.0. Declare the desired test framework directly on the test suite or explicitly declare the test framework implementation dependencies on the test's runtime classpath. Consult the upgrading guide for further information: https://docs.gradle.org/8.6/userguide/upgrading_version_8.html#test_framework_implementation_dependencies
No test executed. This behavior has been deprecated. This will fail with an error in Gradle 9.0. There are test sources present but no test was executed. Please check your test configuration. Consult the upgrading guide for further information: https://docs.gradle.org/8.6/userguide/upgrading_version_8.html#test_task_fail_on_no_test_executed

I don't get this warning when locally running ./gradlew :dataflow:test.
Why is this output in CI and how do we fix this?

[Ao-senXiong]

@wmdietl I used ./gradlew :dataflow:test --warning-mode, let me take a look and make a PR:

./gradlew :dataflow:test --warning-mode all

> Task :dataflow:test
The automatic loading of test framework implementation dependencies has been deprecated. This is scheduled to be removed in Gradle 9.0. Declare the desired test framework directly on the test suite or explicitly declare the test framework implementation dependencies on the test's runtime classpath. Consult the upgrading guide for further information: https://docs.gradle.org/8.6/userguide/upgrading_version_8.html#test_framework_implementation_dependencies
No test executed. This behavior has been deprecated. This will fail with an error in Gradle 9.0. There are test sources present but no test was executed. Please check your test configuration. Consult the upgrading guide for further information: https://docs.gradle.org/8.6/userguide/upgrading_version_8.html#test_task_fail_on_no_test_executed