Adding More Test Cases for a Redux Reducer

Just because you've run a function through one set of inputs, doesn't mean other inputs will behave the same way. This is often true with state management solutions where it's common to memoize responses & cache data. We only end up with 4 tests total for our products reducer, but I'd like you to consider all of the following cases when you're writing reducer tests for your production applications.

• Valid Input
• Valid Input more than once
• Invalid Input
• Invalid Input more than once
• With Existing State
• With No Existing State
• Invalid/Unknown Action Type