As part of CI/CD: Depending on complexity - basic functional tests against the specific endpoint or end-to-end test of API functions (using mocks when APIs aren't available).
Once deployed to pre-prod: Monitor just like prod - end-to-end functional tests w/routing rules to mocks when a certain microservices is unavailable.
As part of CI/CD: Depending on complexity - basic functional tests against the specific endpoint or end-to-end test of API functions (using mocks when APIs aren't available).
Once deployed to pre-prod: Monitor just like prod - end-to-end functional tests w/routing rules to mocks when a certain microservices is unavailable.
Prod: Monitor using end-to-end functional tests.