This chapter has explored how to test drive the integration of a not-so-simple package, Relay. We encountered something new in the use of jest.mock so that we could stub and spy on types coming from an external module. We also used our previously built knowledge to create tests that instrumented multiple modules, all in the name of expressive testing.
We've now explored about as much as this code base can usefully offer us.
In Section 3, Interactivity, we'll begin work in a new code base that will allow us to explore more complex use cases involving undo/redo, animation, and WebSocket manipulation.
In Chapter 10, Building a Logo interpreter, we'll begin by writing new Redux middleware to handle undo/redo behavior.