can fields that have the @Option annotation be abstract? for example in `Test`I see this:

@Incubating
    @Input
    @Option(option = "test-dry-run", description = "Simulate test execution.")
    public abstract Property<Boolean> getDryRun();

Yes.

and then I can just make the whole task class abstract and it will just work?

Yep. Gradle provides a concert subclass / properties as required.

is that documented somewhere?

*concrete

perfect, thanks!