can't spy on nested function call

[lkurylo]

I have a simple store:

export const useFormsContextStore = defineStore('formsContext', () => {
  function makeSomeCalculations() {
    // calculations

    // and fire helper function
    helper();
  }

  function helper() {
    console.log('helper function called from pinia store');
  }

  return {
    calculate: makeSomeCalculations,
    calculateHelper: helper,
    helper,
  };
});

I want to test if helper() method is being called on calculate() execution, so created a unit test with configuration:

describe('Forms Context store tests', () => {
  let pinia: Pinia | undefined = undefined;

  beforeEach(() => {
      pinia = createTestingPinia({
          createSpy: vi.fn,
          stubActions: false,
      });

      setActivePinia(pinia);
  });

  afterEach(() => {
      vi.resetAllMocks();
  });

  it('unit test', async () => {
      const store = useFormsContextStore(pinia);

      store.calculate();

     expect.soft(store.calculate).toHaveBeenCalledOnce();
     expect.soft(store.helper).toHaveBeenCalledOnce();
  });
});

I tthrows exception on last expect:

expected spy to be called once but got 0 times

Here is a link with reproduction: https://stackblitz.com/edit/vitest-dev-vitest-lyex7t?file=test%2FuseFormsContextStore.test.ts

Don't know where the problem is?

[posva]

The problem is that helper is the actual function within the store, not the spy. The spies are useful outside of the store only.