From 4b9c5d886f9c1febe55adf15c38096bf4aaec994 Mon Sep 17 00:00:00 2001
From: Dominik Dorfmeister <office@dorfmeister.cc>
Date: Mon, 16 Dec 2024 18:22:07 +0100
Subject: [PATCH] test: startTransition

---
 .../src/__tests__/transition.test.tsx         | 97 +++++++++++++++++++
 1 file changed, 97 insertions(+)
 create mode 100644 packages/react-query/src/__tests__/transition.test.tsx

diff --git a/packages/react-query/src/__tests__/transition.test.tsx b/packages/react-query/src/__tests__/transition.test.tsx
new file mode 100644
index 0000000000..c79ce27f7d
--- /dev/null
+++ b/packages/react-query/src/__tests__/transition.test.tsx
@@ -0,0 +1,97 @@
+import { afterAll, beforeAll, describe, expect, it } from 'vitest'
+import * as React from 'react'
+import {
+  createRenderStream,
+  useTrackRenders,
+} from '@testing-library/react-render-stream'
+import { QueryClientProvider, useQuery } from '..'
+import { QueryCache } from '../index'
+import { createQueryClient, queryKey, sleep } from './utils'
+
+describe('react transitions', () => {
+  const queryCache = new QueryCache()
+  const queryClient = createQueryClient({
+    queryCache,
+  })
+
+  beforeAll(() => {
+    queryClient.setDefaultOptions({
+      queries: { experimental_prefetchInRender: true },
+    })
+  })
+  afterAll(() => {
+    queryClient.setDefaultOptions({
+      queries: { experimental_prefetchInRender: false },
+    })
+  })
+
+  it('should keep values of old key around with startTransition', async () => {
+    const key = queryKey()
+
+    const renderStream = createRenderStream({ snapshotDOM: true })
+
+    function Loading() {
+      useTrackRenders()
+      return <>loading..</>
+    }
+
+    function Page() {
+      useTrackRenders()
+      const [count, setCount] = React.useState(0)
+      const query = useQuery({
+        queryKey: [key, count],
+        queryFn: async () => {
+          await sleep(10)
+          return 'test' + count
+        },
+      })
+
+      const data = React.use(query.promise)
+
+      return (
+        <div>
+          <button
+            onClick={() => React.startTransition(() => setCount((c) => c + 1))}
+          >
+            increment
+          </button>
+          <div>data: {data}</div>
+        </div>
+      )
+    }
+
+    const rendered = await renderStream.render(
+      <QueryClientProvider client={queryClient}>
+        <React.Suspense fallback={<Loading />}>
+          <Page />
+        </React.Suspense>
+      </QueryClientProvider>,
+    )
+
+    {
+      const { renderedComponents, withinDOM } = await renderStream.takeRender()
+      withinDOM().getByText('loading..')
+      expect(renderedComponents).toEqual([Loading])
+    }
+
+    {
+      const { renderedComponents, withinDOM } = await renderStream.takeRender()
+      withinDOM().getByText('data: test0')
+      expect(renderedComponents).toEqual([Page])
+    }
+
+    rendered.getByRole('button', { name: 'increment' }).click()
+
+    {
+      const { renderedComponents, withinDOM } = await renderStream.takeRender()
+      withinDOM().getByText('data: test0')
+      expect(renderedComponents).toEqual([Page])
+    }
+
+    {
+      const { renderedComponents, withinDOM } = await renderStream.takeRender()
+      withinDOM().getByText('data: test1')
+      expect(renderedComponents).toEqual([Page])
+    }
+  })
+})