Testing

• manual testing is a terrible use of resource, invest in automated testing whenever possible
• unit tests are supposed to be fast so developers can run them frequently without getting bored
• your mocking is dysfunctional if it involves writing things twice
• unit tests are for verifying behaviour and enforcing it
• an integration test can be used to check the parts unit tests can't reach, in particular that the service can communicate with its immediately adjacent services

Analogy

• a dishwasher gets dishes clean by splashing them gently. if you tried that you'd get nowhere, but it is relentless and thorough - that's the difference between manual and automated testing