chore: Add test for custom video file paths

apps/simple-camera/__tests__/visioncamera.video.harness.ts

@@ -9,6 +9,7 @@ import {
 import type {
   CameraDevice,
   CameraDeviceFactory,
+  Recorder,
   RecordingFinishedReason,
 } from 'react-native-vision-camera'
 import { CommonResolutions, VisionCamera } from 'react-native-vision-camera'
@@ -408,6 +409,165 @@ describe('VisionCamera - Video', () => {
     }
   })
 
+  it('records to a custom file path', async () => {
+    const session = await VisionCamera.createCameraSession(false)
+    const videoOutput = VisionCamera.createVideoOutput({
+      targetResolution: CommonResolutions.HD_16_9,
+      enableAudio: false,
+    })
+    await session.configure([
+      {
+        input: backDevice,
+        outputs: [{ output: videoOutput, mirrorMode: 'auto' }],
+        constraints: [],
+      },
+    ])
+    await session.start()
+
+    // Discover the platform-specific app-writable temp directory by
+    // creating a default recorder and reading its chosen file path.
+    // We can't hard-code `/tmp/...` because iOS app sandboxes and Android
+    // app contexts both use platform-specific dynamic paths.
+    const probe = await videoOutput.createRecorder({})
+    const probePath = probe.filePath.replace(/^file:\/\//, '')
+    const tempDir = probePath.substring(0, probePath.lastIndexOf('/'))
+    const ext = Platform.OS === 'ios' ? 'mov' : 'mp4'
+    const customPath = `${tempDir}/visioncamera-custom-${Date.now()}.${ext}`
+
+    const recorder = await videoOutput.createRecorder({ filePath: customPath })
+    expect(recorder.filePath).toContain(customPath)
+
+    let finishedPath: string | undefined
+    let recordingError: Error | undefined
+    try {
+      await recorder.startRecording(
+        (filePath) => {
+          finishedPath = filePath
+        },
+        (error) => {
+          recordingError = error
+        },
+      )
+      await sleep(800)
+      await recorder.stopRecording()
+      await waitUntil(() => finishedPath != null, { timeout: 10_000 })
+
+      expect(recordingError).toBe(undefined)
+      expect(finishedPath).toContain(customPath)
+    } finally {
+      await session.stop()
+    }
+  })
+
+  it('auto-creates parent directories for a nested custom file path', async () => {
+    const session = await VisionCamera.createCameraSession(false)
+    const videoOutput = VisionCamera.createVideoOutput({
+      targetResolution: CommonResolutions.HD_16_9,
+      enableAudio: false,
+    })
+    await session.configure([
+      {
+        input: backDevice,
+        outputs: [{ output: videoOutput, mirrorMode: 'auto' }],
+        constraints: [],
+      },
+    ])
+    await session.start()
+
+    const probe = await videoOutput.createRecorder({})
+    const probePath = probe.filePath.replace(/^file:\/\//, '')
+    const tempDir = probePath.substring(0, probePath.lastIndexOf('/'))
+    const ext = Platform.OS === 'ios' ? 'mov' : 'mp4'
+    // Use multiple non-existent nested folders so the test fails if the
+    // implementation doesn't recursively create parent dirs.
+    const customPath = `${tempDir}/visioncamera-nested-${Date.now()}/sub/dir/recording.${ext}`
+
+    const recorder = await videoOutput.createRecorder({ filePath: customPath })
+    expect(recorder.filePath).toContain(customPath)
+
+    let finishedPath: string | undefined
+    let recordingError: Error | undefined
+    try {
+      await recorder.startRecording(
+        (filePath) => {
+          finishedPath = filePath
+        },
+        (error) => {
+          recordingError = error
+        },
+      )
+      await sleep(800)
+      await recorder.stopRecording()
+      await waitUntil(() => finishedPath != null, { timeout: 10_000 })
+
+      // If the recording finished without error, the nested directories
+      // had to be created on the fly - otherwise the encoder couldn't
+      // have written any bytes.
+      expect(recordingError).toBe(undefined)
+      expect(finishedPath).toContain(customPath)
+    } finally {
+      await session.stop()
+    }
+  })
+
+  it('fails to record when given an unwritable file path', async () => {
+    const session = await VisionCamera.createCameraSession(false)
+    const videoOutput = VisionCamera.createVideoOutput({
+      targetResolution: CommonResolutions.HD_16_9,
+      enableAudio: false,
+    })
+    await session.configure([
+      {
+        input: backDevice,
+        outputs: [{ output: videoOutput, mirrorMode: 'auto' }],
+        constraints: [],
+      },
+    ])
+    await session.start()
+
+    // The filesystem root is read-only inside both iOS and Android app
+    // sandboxes, so writing to `/<file>.mp4` must fail somehow.
+    const invalidPath = `/visioncamera-cannot-write-${Date.now()}.mp4`
+    let createError: Error | undefined
+    let startError: Error | undefined
+    let recordingError: Error | undefined
+
+    try {
+      let recorder: Recorder | undefined
+      try {
+        recorder = await videoOutput.createRecorder({ filePath: invalidPath })
+      } catch (e) {
+        createError = e as Error
+      }
+      if (recorder != null) {
+        try {
+          await recorder.startRecording(
+            () => {},
+            (error) => {
+              recordingError = error
+            },
+          )
+        } catch (e) {
+          startError = e as Error
+        }
+        // The error may surface synchronously (startRecording rejection)
+        // or asynchronously (onRecordingError callback). Wait briefly for
+        // the async case, but don't fail if the sync case already fired.
+        await waitUntil(() => startError != null || recordingError != null, {
+          timeout: 5_000,
+        }).catch(() => {
+          // Timed out without an error - the assertion below will fail.
+        })
+      }
+    } finally {
+      await session.stop()
+    }
+
+    expect(
+      createError != null || startError != null || recordingError != null,
+    ).toBe(true)
+  })
+
   it('returns supported video codecs on iOS after the output is attached', async () => {
     if (Platform.OS !== 'ios') {
       console.log('[SKIP] getSupportedVideoCodecs: iOS only')