data-client-vue-testing

# Vue Testing Patterns (@data-client/vue) ## Composable Testing with renderDataCompose() ```typescript import { renderDataCompose } from '../test'; import { reactive, computed } from 'vue'; it('useQuery() should return cached data', () => { const { result } = renderDataCompose( () => useQuery(Article, { id: 5 }), { initialFixtures: [ { endpoint: ArticleResource.get, args: [{ id: 5 }], response: { id: 5, title: 'hi ho', content: 'whatever' }, }, ], }, ); expect(result.current?.value).toEqual(Article.fromJS({ id: 5, title: 'hi ho', content: 'whatever' })); }); ``` **Options:** - `initialFixtures` - Pre-populate store state (static fixtures) - `resolverFixtures` - Intercept requests with dynamic responses - `props` - Reactive props object (use `reactive()`) - `managers`, `initialState`, `gcPolicy` - Custom configuration **Return values:** - `result.current` - Composable return value (undefined when suspended, Promise when resolved for useSuspense) - `controller` - Controller instance for manual actions - `wrapper` - Vue Test Utils wrapper - `cleanup()` - Cleanup function (always call in afterEach/after test) - `allSettled()` - Wait for all pending promises - `waitForNextUpdate()` - Wait for composable to resolve from suspended state ## Component Testing with mountDataClient() ```typescript import { mountDataClient } from '../test'; import { defineComponent, h, reactive } from 'vue'; it('should render article component', async () => { const ArticleComp = defineComponent({ props: { id: Number }, async setup(props) { const article = await useSuspense(ArticleResource.get, { id: props.id }); return () => h('div', [ h('h3', article.value.title), h('p', article.value.content), ]); }, }); const props = reactive({ id: 5 }); const { wrapper, cleanup } = mountDataClient(ArticleComp, { props, initialFixtures: [ { endpoint: ArticleResource.get, args: [{ id: 5 }], response: { id: 5, title: 'hi ho', content: 'whatever' }, }, ], }); await flushUntil(wrapper, () => wrapper.find('h3').exists()); expect(wrapper.find('h3').text()).toBe('hi ho'); cleanup(); }); ``` **Features:** - Suspense is automatically integrated (shows fallback while loading) - Use `data-testid="suspense-fallback"` to test loading state - Returns same utilities as `renderDataCompose()` plus `wrapper` ## Async Waiting Patterns **flushUntil helper (for component tests):** ```typescript async function flushUntil(wrapper: any, predicate: () => boolean, tries = 100) { for (let i = 0; i < tries; i++) { if (predicate()) return; await Promise.resolve(); await nextTick(); await new Promise(resolve => setTimeout(resolve, 0)); } } // Usage: await flushUntil(wrapper, () => wrapper.find('h3').exists()); await flushUntil(wrapper, () => wrapper.find('h3').text() === 'Expected Title'); ``` **waitForNextUpdate (for composable tests):** ```typescript const { result, waitForNextUpdate } = renderDataCompose(() => useSuspense(...)); // Initially suspended expect(result.current).toBeUndefined(); // Wait for resolution await waitForNextUpdate(); expect(result.current).toBeInstanceOf(Promise); // Await the promise to get the reactive ComputedRef const dataRef = await result.current; expect(dataRef.value.title).toBe('hi ho'); ``` ## Reactive Props Testing **Pattern 1: Testing prop changes:** ```typescript const props = reactive({ id: 1 }); const { result } = renderDataCompose( () => useQuery(Article, computed(() => ({ id: props.id }))), { initialFixtures: [ { endpoint: ArticleResource.get, args: [{ id: 1 }], response: { id: 1, title: 'First' } }, { endpoint: ArticleResource.get, args: [{ id: 2 }], response: { id: 2, title: 'Second' } }, ], }, ); expect(result.current?.value?.title).toBe('First'); // Change props - result automatically updates props.id = 2; expect(result.current?.value?.title).toBe('Second'); ``` **Pattern 2: Conditional arguments (null handling):** ```typescript const props = reactive({ id: 1 as number | null }); const { result } = renderDataCompose( (props: { id: number | null }) => useSuspense(ArticleResource.get, computed(() => props.id !== null ? { id: props.id } : null)), { props }, ); await waitForNextUpdate(); const articleRef = await result.current; expect(articleRef.value).toBeDefined(); // Set to null - becomes undefined props.id = null; await nextTick(); expect(articleRef.value).toBeUndefined(); ``` ## Fixtures and Interceptors **Static Fixture:** ```typescript { endpoint: ArticleResource.get, args: [{ id: 5 }], response: { id: 5, title: 'hi ho', content: 'whatever' }, } ``` **Dynamic Interceptor:** ```typescript resolverFixtures: [ { endpoint: ArticleResource.get, response: ({ id }) => ({ id, title: `Article ${id}`, content: 'dynamic' }), }, ] ``` **Error Fixture:** ```typescript { endpoint: ArticleResource.get, args: [{ id: 5 }], response: new Error('Not found'), error: true, } ``` ## Testing Mutations ```typescript it('should update collection when pushed', async () => { const { result, controller, waitForNextUpdate } = renderDataCompose( () => useQuery(ArticleResource.getList.schema, {}), { initialFixtures: [ { endpoint: ArticleResource.getList, args: [], response: [{ id: 1, title: 'First' }] }, ], resolverFixtures: [ { endpoint: ArticleResource.getList.push, response: (body) => body }, ], }, ); expect(result.current?.value?.length).toBe(1); await controller.fetch(ArticleResource.getList.push, { id: 2, title: 'Second', content: 'new', }); await waitForNextUpdate(); expect(result.current?.value?.length).toBe(2); }); ``` ## Testing with Controller **setResponse() for instant updates:** ```typescript const { controller } = renderDataCompose(...); await waitForNextUpdate(); const dataRef = await result.current; expect(dataRef.value.title).toBe('Original'); controller.setResponse( ArticleResource.get, { id: 5 }, { id: 5, title: 'Updated', content: 'new content' } ); await nextTick(); expect(dataRef.value.title).toBe('Updated'); // Reactive! ``` **fetch() for mutations:** ```typescript await controller.fetch( ArticleResource.update, { id: 5 }, { title: 'Mutated', content: 'mutated content' } ); await nextTick(); ``` ## Testing with nock (HTTP Mocking) Use nock when a test must exercise the real fetch path — verifying URL construction, headers, request bodies, retries, or anything in your `RestEndpoint`/`Resource` networking layer. For pure store/state behavior, prefer `initialFixtures`/`resolverFixtures` (lighter and faster). Minimal shape: ```typescript import nock from 'nock'; beforeAll(() => { nock(/.*/) .persist() .defaultReplyHeaders({ 'Access-Control-Allow-Origin': '*', 'Content-Type': 'application/json' }) .options(/.*/).reply(200) // CORS preflight (required in JSDOM) .get('/article/5').reply(200, { id: 5, title: 'hi ho' }); }); afterAll(() => nock.cleanAll()); ``` For dynamic server state, mutating-closure replies, request spying with `jest.fn()`, error responses, and mixing nock with fixtures, see [references/nock-http-mocking.md](references/nock-http-mocking.md). ## Testing Polling and Subscriptions For composables with `pollFrequency`, `useLive`, or `useSubscription`, use fake timers so polls fire deterministically. Core flow: 1. `jest.useFakeTimers()` **before** mount/render (so the interval is created under fake timers). 2. Render, then `jest.advanceTimersByTime(frequency)` to drive the initial fetch. 3. Mutate the response (e.g. `responseMock.mockReturnValue(...)`), advance time again, `await allSettled()` and `await nextTick()`. 4. Restore real timers in `afterEach`: `jest.useRealTimers()`. Quick example: ```typescript jest.useFakeTimers(); const responseMock = jest.fn(() => payload); const { result, allSettled, waitForNextUpdate, cleanup } = await renderDataCompose( () => useSuspense(PollingArticleResource.get, { id: payload.id }), { resolverFixtures: [{ endpoint: PollingArticleResource.get, response: responseMock }] }, ); jest.advanceTimersByTime(frequency); await allSettled(); await waitForNextUpdate(); const articleRef = await result; responseMock.mockReturnValue({ ...payload, title: 'updated' }); jest.advanceTimersByTime(frequency); await allSettled(); await nextTick(); expect(articleRef!.value.title).toBe('updated'); jest.useRealTimers(); cleanup(); ``` For unsubscribe patterns, component-level polling tests, fake-timer-safe `flushUntil`, polling via nock, and common pitfalls, see [references/polling-subscriptions.md](references/polling-subscriptions.md). ## Vue Suspense Behavior **useSuspense() returns Promise → ComputedRef:** ```typescript const { result, waitForNextUpdate } = renderDataCompose(() => useSuspense(ArticleResource.get, { id: 5 }) ); // Initially suspended (undefined) expect(result.current).toBeUndefined(); // Wait for resolution await waitForNextUpdate(); // Now it's a Promise expect(result.current).toBeInstanceOf(Promise); // Await once to get reactive ComputedRef const articleRef = await result.current; // The ref is reactive - updates automatically expect(articleRef.value.title).toBe('hi ho'); // After controller.setResponse() or controller.fetch(): await nextTick(); expect(articleRef.value.title).toBe('Updated'); // Auto-updated! ``` **useQuery() returns ComputedRef directly:** ```typescript const { result } = renderDataCompose(() => useQuery(Article, { id: 5 })); // Synchronously available (or undefined if not in store) expect(result.current?.value).toBeDefined(); expect(result.current?.value?.title).toBe('hi ho'); // Also reactive - updates automatically ``` ## Best Practices - **Always call cleanup()** - Prevents memory leaks and test pollution - **Use renderDataCompose()** for composables (useQuery, useSuspense, useLive) - **Use mountDataClient()** for components