docs: minor fixes

packages/docs/cookbook/testing.md

@@ -71,7 +71,6 @@ beforeEach(() => {
   title="Watch a free video of Mastering Pinia about testing stores"
 /> -->
 
-
 This can be achieved with `createTestingPinia()`, which returns a pinia instance designed to help unit tests components.
 
 Start by installing `@pinia/testing`:
@@ -214,6 +213,8 @@ const store = mockedStore(useSomeStore)
 store.someAction.mockResolvedValue('some value')
 ```
 
+If you are interesting in learning more tricks like this, you should check out the Testing lessons on [Mastering Pinia](https://masteringpinia.com/lessons/exercise-mocking-stores-introduction).
+
 ### Specifying the createSpy function
 
 When using Jest, or vitest with `globals: true`, `createTestingPinia` automatically stubs actions using the spy function based on the existing test framework (`jest.fn` or `vitest.fn`). If you are not using `globals: true` or using a different framework, you'll need to provide a [createSpy](/api/interfaces/pinia_testing.TestingOptions.html#createspy) option: