I have a simplified exemple of what i try to accomplish :

// ResourceRouter.ts
class ResourceRouter extends ResourceApi {
  static init(token: string) {
    return new ResourceRouter(token)
  }

  public async getResource (id: number) {
    try {
        const res : AxiosResponse<Resource> await this.get("/my-endpoint-url", id)
        return res.data 
    } catch (error: unknown) { throw error; }
  }
}

// useGetResource.ts
const useGetResource = () => {
    const resourceRouter = ResourceRouter.init("my_token")

    const queryOpts = queryOptions({
        queryKey:["get_resource"]
        queryFn: () => resourceRouter.getResource(1)
    })

    const query = useQuery(queryOpts)

    return query
}

// useGetResource.test.ts

const ResourceRouteInitSpy = vi.spyOn(ResourceRouter, "init");

describe("useGetResource", () => {

  it("Should get resource with correct id", async () => {
    const { result } = renderHook(() => useGetResource(), { wrapper: QueryClientWrapper })

    expect(resourceRouterInitSpy).toHaveBeenCalledWith("token_mock") // called

    const resourceRouterGetResourceSpy = vi.spyOn(ResourceRouter.prototype, "getUser") 

    await waitFor(() => expect(ResourceRouterGetResourceSpy).toHaveBeenCalled()) // not called
  })
})

In my test file, I try to spy on my resourceRouter.getResource instance method to ensure that it has been called with a specific id. I can do that for the static init method, but not with the getResource method from the prototype. Why ?

I tried to expose the resourceRouter instance in the return value of my custom hook so i can access it from the test file, but the method seems not to be called either.

Regards,