REVIEW-4556: Don't serialize the ModuleVersionIdentifier as it's redundant with the ModuleComponentIdentifier
REVIEW-4445: Verify cause of failure in integ test
REVIEW-4436: More test coverage in the spec

Document some test coverage that should be implemented once cache expiry can be configured for the Artifact Query API
REVIEW-4436: Test caching optional jar artifact for packaging='pom'

- Check that no requests are made for optional jar when cached
- Check that new optional artifact is detected on cache expiry
- Check that removal of optional artifact is detected on cache expiry