clear nextRenderTimeout in resetNextRender

Author: phryneas

src/renderStream/__tests__/waitForNextRender.test.tsx

@@ -0,0 +1,45 @@
+import {expect, jest, test} from '@jest/globals'
+import {createRenderStream} from '@testing-library/react-render-stream'
+import * as React from 'react'
+import {flushSync} from 'react-dom'
+
+test.each([false, true])(
+  'a completed wait cannot clear a later waiter (snapshot error: %s)',
+  async snapshotError => {
+    const error = new Error('snapshot failed')
+    const stream = createRenderStream<{value: number}>({
+      onRender({snapshot}) {
+        if (snapshotError && snapshot.value === 1) throw error
+      },
+    })
+    let update: React.Dispatch<React.SetStateAction<number>>
+    function Component() {
+      const [value, setValue] = React.useState(0)
+      update = setValue
+      stream.replaceSnapshot({value})
+      return null
+    }
+    await stream.render(<Component />)
+    await stream.takeRender()
+
+    jest.useFakeTimers()
+    try {
+      const first = stream.takeRender({timeout: 100}).then(
+        () => undefined,
+        failure => failure,
+      )
+      flushSync(() => update!(1))
+      await jest.advanceTimersByTimeAsync(0)
+      expect(await first).toBe(snapshotError ? error : undefined)
+
+      const second = stream.takeRender({timeout: 200}).catch(failure => failure)
+      // Cross the first wait's original deadline while the second is pending.
+      await jest.advanceTimersByTimeAsync(100)
+      flushSync(() => update!(2))
+      await jest.advanceTimersByTimeAsync(100)
+      expect(await second).toMatchObject({snapshot: {value: 2}})
+    } finally {
+      jest.useRealTimers()
+    }
+  },
+)

src/renderStream/createRenderStream.tsx

@@ -142,8 +142,11 @@ export function createRenderStream<
 
   let nextRender: Promise<Render<Snapshot, Q>> | undefined,
     resolveNextRender: ((render: Render<Snapshot, Q>) => void) | undefined,
-    rejectNextRender: ((error: unknown) => void) | undefined
+    rejectNextRender: ((error: unknown) => void) | undefined,
+    nextRenderTimeout: ReturnType<typeof setTimeout> | undefined
   function resetNextRender() {
+    clearTimeout(nextRenderTimeout)
+    nextRenderTimeout = undefined
     nextRender = undefined
     resolveNextRender = undefined
     rejectNextRender = undefined
@@ -396,14 +399,14 @@ export function createRenderStream<
             resolveNextRender = resolve
             rejectNextRender = reject
           }),
-          new Promise<Render<Snapshot, Q>>((_, reject) =>
-            setTimeout(() => {
+          new Promise<Render<Snapshot, Q>>((_, reject) => {
+            nextRenderTimeout = setTimeout(() => {
               const error = new WaitForRenderTimeoutError()
               Error.captureStackTrace(error, stream.waitForNextRender)
               reject(error)
               resetNextRender()
-            }, timeout),
-          ),
+            }, timeout)
+          }),
         ])
       }
       return nextRender