CLC-3696 Followup increasing test coverage on Cacheable
CLC-3696 Even more cacheable test coverage
CLC-3816 More cacheable test coverage, and fix nil read bug
CLC-3816 Check the jsonification behavior of nil
Merge pull request #2581 from ctweney/smart_fetch_test_coverage

CLC-3816 More test coverage and tiny bug fix for smart_fetch