Default test suite behavior is no longer to use JUnit 4

[tresat]

This is incorrectly noted here: https://docs.gradle.org/current/userguide/jvm_test_suite_plugin.html#sec:jvm_test_suite_tasks

This adds a new integration test to demonstrates this behavior. This is intentional, see:

gradle/subprojects/plugins/src/main/java/org/gradle/api/plugins/jvm/internal/DefaultJvmTestSuite.java

Line 125 in 74fb3be

if (!name.equals(JvmTestSuitePlugin.DEFAULT_TEST_SUITE_NAME)) {

This PR also adjust docs to note this.

[tresat]

@bot-gradle test QFL

[bot-gradle]

OK, I've already triggered the following builds for you:

• QuickFeedbackLinux build

[DPUkyle]

LGTM, though I could have sworn we set JUnit 4 as a fallback when nothing was specified.

This must have changed when we encountered difficulties changing the framework in multiple places, i.e. set options on the suite object, then later tweak on an individual Test task. Perhaps at this point we added the requirement to set the framework explicitly?

[tresat]

LGTM, though I could have sworn we set JUnit 4 as a fallback when nothing was specified.

We definitely did. Then the behavior changed, to deal with the options issues, I think, and we forgot to update the docs. Now the test should confirm and document the behavior as well, and we can stop confusing any users wondering about why this isn't working.

[octylFractal]

Reminder to retarget this at release for 7.4.

[tresat]

Replaced by #19505