Add unit tests for Kettle populate_start (#19025)
Add unit tests for Kettle populate_start (#19025)

* Add unit tests for Kettle populate_start

Extending the effort to lock down kettle unit tests

* Update to clean unit tests from repeat params

* Move update attr out of check

* Add param for testname

* Fix tests to honor json

* Spacing in base attrs

* Fix merge wuth finished json tests
michelle192837/test-infra,BenTheElder/test-infra,BenTheElder/test-infra,dims/test-infra,monopole/test-infra,brahmaroutu/test-infra,cblecker/test-infra,brahmaroutu/test-infra,michelle192837/test-infra,pwittrock/test-infra,cblecker/test-infra,pwittrock/test-infra,jessfraz/test-infra,cjwagner/test-infra,kubernetes/test-infra,jessfraz/test-infra,cjwagner/test-infra,fejta/test-infra,kubernetes/test-infra,dims/test-infra,pwittrock/test-infra,jessfraz/test-infra,kubernetes/test-infra,dims/test-infra,BenTheElder/test-infra,cblecker/test-infra,brahmaroutu/test-infra,dims/test-infra,michelle192837/test-infra,monopole/test-infra,monopole/test-infra,dims/test-infra,BenTheElder/test-infra,fejta/test-infra,brahmaroutu/test-infra,cblecker/test-infra,monopole/test-infra,dims/test-infra,BenTheElder/test-infra,michelle192837/test-infra,cjwagner/test-infra,fejta/test-infra,cjwagner/test-infra,pwittrock/test-infra,kubernetes/test-infra,jessfraz/test-infra,michelle192837/test-infra,jessfraz/test-infra,cblecker/test-infra,monopole/test-infra,cblecker/test-infra,brahmaroutu/test-infra,michelle192837/test-infra,fejta/test-infra,fejta/test-infra,cjwagner/test-infra,brahmaroutu/test-infra,pwittrock/test-infra,fejta/test-infra,cjwagner/test-infra,kubernetes/test-infra,jessfraz/test-infra,kubernetes/test-infra,monopole/test-infra,BenTheElder/test-infra