Jargon:

Virtual Service – this is a network endpoint that is a mock up of a real service, however it is simple, fast to launch, and can be setup and controlled from test automation code.

Provider – the service that is creating information

Consumer – the client that is consuming information from a Provider.

The Agile Thoughts series on the Test Automation Pyramid is a good way to learn about macro and micro testing: https://agilenoir.biz/en/agilethoughts/test-automation-pyramid-series/

These TDD episodes are a way to learn about TDD: https://agilenoir.biz/podcast/009-introducing-the-test-driven-development-series/