feat(test): support unstubbing actions

packages/docs/cookbook/testing.md

@@ -164,6 +164,33 @@ store.someAction()
 expect(store.someAction).toHaveBeenCalledTimes(1)
 ```
 
+If you want to normally execute only some of the actions with `stubActions: true` you can reset them with `mockRestore`:
+
+```js
+const wrapper = mount(Counter, {
+  global: {
+    // stubActions is set to 'true' by default
+    plugins: [createTestingPinia()],
+  },
+})
+
+const store = useSomeStore()
+
+// All subsequent calls of this action WILL execute the implementation defined by the store
+store.someAction.mockRestore()
+
+// Runs the actual implementation
+store.someAction()
+
+// Runs the mocked function
+store.anotherAction()
+
+// the spy is kept on unmocked functions as well
+expect(store.someAction).toHaveBeenCalledTimes(1)
+```
+
+Note: this behaviour is supported only when using either jest or vitest.
+
 ### Mocking the returned value of an action
 
 Actions are automatically spied but type-wise, they are still the regular actions. In order to get the correct type, we must implement a custom type-wrapper that applies the `Mock` type to each action. **This type depends on the testing framework you are using**. Here is an example with Vitest:

packages/testing/src/testing.spec.ts

@@ -138,6 +138,33 @@ describe('Testing', () => {
           expect(counter.increment).toHaveBeenCalledTimes(4)
           expect(counter.increment).toHaveBeenLastCalledWith(10)
         })
+
+        it(`can unstub actions with ${name}`, () => {
+          const { counter, wrapper } = factory(undefined, useStore)
+
+          // @ts-ignore
+          counter.increment.mockRestore()
+
+          counter.increment()
+          expect(counter.n).toBe(1)
+          expect(counter.increment).toHaveBeenCalledTimes(1)
+          expect(counter.increment).toHaveBeenLastCalledWith()
+
+          counter.increment(5)
+          expect(counter.n).toBe(6)
+          expect(counter.increment).toHaveBeenCalledTimes(2)
+          expect(counter.increment).toHaveBeenLastCalledWith(5)
+
+          wrapper.findAll('button')[0].trigger('click')
+          expect(counter.n).toBe(7)
+          expect(counter.increment).toHaveBeenCalledTimes(3)
+          expect(counter.increment).toHaveBeenLastCalledWith()
+
+          wrapper.findAll('button')[1].trigger('click')
+          expect(counter.n).toBe(17)
+          expect(counter.increment).toHaveBeenCalledTimes(4)
+          expect(counter.increment).toHaveBeenLastCalledWith(10)
+        })
       })
     })
 

packages/testing/src/testing.ts

@@ -13,6 +13,10 @@ import {
 // while the other types hide internal properties
 import type { ComputedRefImpl } from '@vue/reactivity'
 
+type MockFn = ((...args: any[]) => any) & {
+  mockReturnValue: (value: any) => MockFn
+}
+
 export interface TestingOptions {
   /**
    * Allows defining a partial initial state of all your stores. This state gets applied after a store is created,
@@ -61,7 +65,7 @@ export interface TestingOptions {
    * with `jest.fn` in Jest projects or `vi.fn` in Vitest projects if
    * `globals: true` is set.
    */
-  createSpy?: (fn?: (...args: any[]) => any) => (...args: any[]) => any
+  createSpy?: (fn?: (...args: any[]) => any) => MockFn
 }
 
 /**
@@ -76,7 +80,7 @@ export interface TestingPinia extends Pinia {
 declare var vi:
   | undefined
   | {
-      fn: (fn?: (...args: any[]) => any) => (...args: any[]) => any
+      fn: (fn?: (...args: any[]) => any) => MockFn
     }
 
 /**
@@ -135,15 +139,30 @@ export function createTestingPinia({
     )
   }
 
+  const trySpyWithMock = (fn: any) => {
+    try {
+      // user provided createSpy might not have a mockReturnValue similar to jest and vitest
+      return createSpy(fn).mockReturnValue(undefined)
+    } catch (e) {
+      return createSpy()
+    }
+  }
+
   // stub actions
   pinia._p.push(({ store, options }) => {
     Object.keys(options.actions).forEach((action) => {
       if (action === '$reset') return
-      store[action] = stubActions ? createSpy() : createSpy(store[action])
+      store[action] = stubActions
+        ? trySpyWithMock(store[action])
+        : createSpy(store[action])
     })
 
-    store.$patch = stubPatch ? createSpy() : createSpy(store.$patch)
-    store.$reset = stubReset ? createSpy() : createSpy(store.$reset)
+    store.$patch = stubPatch
+      ? trySpyWithMock(store.$patch)
+      : createSpy(store.$patch)
+    store.$reset = stubReset
+      ? trySpyWithMock(store.$reset)
+      : createSpy(store.$reset)
   })
 
   if (fakeApp) {