Sources not attached for dependency with test classifier

I am consuming jsr107’s TCK tests to run them against my implementation. The entire TCK, tests and all, are published to Maven Central. With a little Gradle magic, the tests run against my implementation and fail spectacularly since its incomplete.

Unfortunately Eclipse is unable to attach the sources for the tests. This makes it hard to debug by stepping through the tests. Any advise on how to coerce Eclipse to discover the sources, which are on Central?