Test Doubles in the Software Engineering Community

Each test renders the entire application with its own data set. The pattern is known as test doubles in the software engineering testing community. We have a stub, a mock and a fake. A fake behaves exactly like the real thing only. It's implemented differently. So what we actually have, we have two types of tests: slow tests and fast tests. They usually would run against something like Docker or in case of Firebase, it runs against the emulator suite. And then the fast tests are component tests and they are all running in memory. These tests that work on React use JSTOM but no IO,. No Use JSTOM and I'm using fix.