Spying on the Dependency Method
Learn how to use spying on a dependency method, set it up, and use it for unit testing.
We'll cover the following...
We studied how stubbing a dependency is very simple, but it is not always possible. Using a stub is not the only way to isolate logic in a unit test. We don’t have to replace the entire dependency—only the parts our component uses. Replacing certain parts means we point out specific methods on the dependency and assign a spy to them. A spy can answer what we want it to answer, but we can also see how many times it was called and with what arguments. So, a spy gives us much more information about what is happening.
There are two ways to set up a spy in a dependency:
Inject the actual ...