Composite Build and Classifier

I have a core build which creates a code jar (without classifier) and a tests jar (with classifier “tests”). This is declarded using:

// tests jar
task testJar(type: Jar) {
	classifier = 'tests'
	from sourceSets.test.output

// artifacts
artifacts {
	archives jar, testJar

From another project I am referencing this test jar as:

// dependencies
dependencies {
	testInclude group: 'group', name: 'core-main', version: '1.0.0', classifier: 'tests'

testInclude is a custom configuration that gets extracted into a build directory to run the tests.

The problem is that if I combine these builds into a composite build I get the error:

Execution failed for task ':explodedTests'.
> Could not resolve all files for configuration ':testInclude'.
   > Could not find core-main-tests.jar (project :core:core-main).

What am I doing wrong or does it simply not work with composite builds? In that case what are the alternatives?

Yes I’ve read (in old posts) that composite builds don’t support classifiers but according to the error message the classifier is considered. So I guess the old posts are out of date. The problem just seems to be that the searched jar doesn’t contain the version because a file core-main-1.0.0-tests.jar is created?

Could someone comment as to whether this feature is coming anytime soon? All the references to composite builds supporting classifiers just seem to say “it’s on our radar”.

In the meantime, is there any workaround available?

Since gradle 5.6 you can use testFixtures to solve the described problem: