More of an OP problem actually 
The failure was caused by a --cmdline-option="/had/a/file/path/within/quotes". Windows seemed to be happy with such a quoted path. Still not 100% sure why they’re a no-go on *nix.
With the quotes, I got the exact same failure outcomes on Linux that you got on Mac.
Removing the quotes, fixed the problem on Linux. So hopefully you’ll have the same working result now on Mac.
Please observe very closely the part of the attached recording where I show Eclipse’s Java Build Path after I run the :eclipse task.
It’s important to remember that running that task triggers Eclipse Modulefication. It, :test and Run As Gradle Test all have the same effect of adding the dependencies to the module path. If you forget to do one of those three, then you should expect some kind of JPMS module-related error.
Notice also that I point out that yellow and black yield sign that Eclipse alerts you to on the Java Build Path dialog? That’s also pretty important. After you do the Eclipse Modulefication, you should check that property page and click the Apply button to get the module path to take effect. Again though: when the jpmsOpts property is not used, that step can be skipped.
Please let me know if it still isn’t working on Mac? And I’ll go back to the drawing board.
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