Thank you for looking into my question.
I downloaded the spock-master.zip, unzipped, and ran a "gradlew clean build". I copied the jar files, currently:
spock-core-1.2-SNAPSHOT-groovy-2.4.jar
spock-core-1.2-SNAPSHOT-groovy-2.4-javadoc.jar
spock-core-1.2-SNAPSHOT-groovy-2.4-sources.jar
to my libs folder for my project.
That's how I finally was able to go to Settings -> Project Structure, app, Dependencies and add a Test Compile entry for the spock-core jar from above.
I am hoping there's an easier path. I'd also like to make this addition to my Android Studio installation and not have to repeat it for each project.
Is all of that necessary? Is that how you're supposed to do it? It seems like a lot of steps. Many thanks, Brian