Shift left testing means testing at the API and component level. To do this accurately, you need to isolate the functionality under test. This is where mock services come in. Virtualize parts of the system that are not under test, or not available (eg, still in development), and get discrete insight into the quality and performance of what you’re testing. Use open source tools, API specs, or UI to create them, and then reuse and share in a virtual catalogue.
