packages/camera/camera_android_camerax/test/android_camera_camerax_test.dart - mirrors/packages - Git at Google

 // Copyright 2013 The Flutter Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 import 'dart:async';

 import 'package:async/async.dart';
 import 'package:camera_android_camerax/camera_android_camerax.dart';
 import 'package:camera_android_camerax/src/camera.dart';
 import 'package:camera_android_camerax/src/camera_info.dart';
 import 'package:camera_android_camerax/src/camera_selector.dart';
 import 'package:camera_android_camerax/src/camerax_library.g.dart';
 import 'package:camera_android_camerax/src/preview.dart';
 import 'package:camera_android_camerax/src/process_camera_provider.dart';
 import 'package:camera_android_camerax/src/system_services.dart';
 import 'package:camera_android_camerax/src/use_case.dart';
 import 'package:camera_platform_interface/camera_platform_interface.dart';
 import 'package:flutter/services.dart' show DeviceOrientation;
 import 'package:flutter/widgets.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:mockito/annotations.dart';
 import 'package:mockito/mockito.dart';

 import 'android_camera_camerax_test.mocks.dart';

 @GenerateNiceMocks(<MockSpec<Object>>[
   MockSpec<Camera>(),
   MockSpec<CameraInfo>(),
   MockSpec<CameraSelector>(),
   MockSpec<Preview>(),
   MockSpec<ProcessCameraProvider>(),
 ])
 @GenerateMocks(<Type>[BuildContext])
 void main() {
   TestWidgetsFlutterBinding.ensureInitialized();

   test('Should fetch CameraDescription instances for available cameras',
       () async {
     // Arrange
     final MockAndroidCameraCamerax camera = MockAndroidCameraCamerax();
     camera.processCameraProvider = MockProcessCameraProvider();
     final List<dynamic> returnData = <dynamic>[
       <String, dynamic>{
         'name': 'Camera 0',
         'lensFacing': 'back',
         'sensorOrientation': 0
       },
       <String, dynamic>{
         'name': 'Camera 1',
         'lensFacing': 'front',
         'sensorOrientation': 90
       }
     ];

     // Create mocks to use
     final MockCameraInfo mockFrontCameraInfo = MockCameraInfo();
     final MockCameraInfo mockBackCameraInfo = MockCameraInfo();

     // Mock calls to native platform
     when(camera.processCameraProvider!.getAvailableCameraInfos()).thenAnswer(
         (_) async => <MockCameraInfo>[mockBackCameraInfo, mockFrontCameraInfo]);
     when(camera.mockBackCameraSelector
             .filter(<MockCameraInfo>[mockFrontCameraInfo]))
         .thenAnswer((_) async => <MockCameraInfo>[]);
     when(camera.mockBackCameraSelector
             .filter(<MockCameraInfo>[mockBackCameraInfo]))
         .thenAnswer((_) async => <MockCameraInfo>[mockBackCameraInfo]);
     when(camera.mockFrontCameraSelector
             .filter(<MockCameraInfo>[mockBackCameraInfo]))
         .thenAnswer((_) async => <MockCameraInfo>[]);
     when(camera.mockFrontCameraSelector
             .filter(<MockCameraInfo>[mockFrontCameraInfo]))
         .thenAnswer((_) async => <MockCameraInfo>[mockFrontCameraInfo]);
     when(mockBackCameraInfo.getSensorRotationDegrees())
         .thenAnswer((_) async => 0);
     when(mockFrontCameraInfo.getSensorRotationDegrees())
         .thenAnswer((_) async => 90);

     final List<CameraDescription> cameraDescriptions =
         await camera.availableCameras();

     expect(cameraDescriptions.length, returnData.length);
     for (int i = 0; i < returnData.length; i++) {
       final Map<String, Object?> typedData =
           (returnData[i] as Map<dynamic, dynamic>).cast<String, Object?>();
       final CameraDescription cameraDescription = CameraDescription(
         name: typedData['name']! as String,
         lensDirection: (typedData['lensFacing']! as String) == 'front'
             ? CameraLensDirection.front
             : CameraLensDirection.back,
         sensorOrientation: typedData['sensorOrientation']! as int,
       );
       expect(cameraDescriptions[i], cameraDescription);
     }
   });

   test(
       'createCamera requests permissions, starts listening for device orientation changes, and returns flutter surface texture ID',
       () async {
     final MockAndroidCameraCamerax camera = MockAndroidCameraCamerax();
     camera.processCameraProvider = MockProcessCameraProvider();
     const CameraLensDirection testLensDirection = CameraLensDirection.back;
     const int testSensorOrientation = 90;
     const CameraDescription testCameraDescription = CameraDescription(
         name: 'cameraName',
         lensDirection: testLensDirection,
         sensorOrientation: testSensorOrientation);
     const ResolutionPreset testResolutionPreset = ResolutionPreset.veryHigh;
     const bool enableAudio = true;
     const int testSurfaceTextureId = 6;

     when(camera.testPreview.setSurfaceProvider())
         .thenAnswer((_) async => testSurfaceTextureId);

     expect(
         await camera.createCamera(testCameraDescription, testResolutionPreset,
             enableAudio: enableAudio),
         equals(testSurfaceTextureId));

     // Verify permissions are requested and the camera starts listening for device orientation changes.
     expect(camera.cameraPermissionsRequested, isTrue);
     expect(camera.startedListeningForDeviceOrientationChanges, isTrue);

     // Verify CameraSelector is set with appropriate lens direction.
     expect(camera.cameraSelector, equals(camera.mockBackCameraSelector));

     // Verify the camera's Preview instance is instantiated properly.
     expect(camera.preview, equals(camera.testPreview));

     // Verify the camera's Preview instance has its surface provider set.
     verify(camera.preview!.setSurfaceProvider());
   });

   test(
       'initializeCamera throws AssertionError when createCamera has not been called before initializedCamera',
       () async {
     final AndroidCameraCameraX camera = AndroidCameraCameraX();
     expect(() => camera.initializeCamera(3), throwsAssertionError);
   });

   test('initializeCamera sends expected CameraInitializedEvent', () async {
     final MockAndroidCameraCamerax camera = MockAndroidCameraCamerax();
     camera.processCameraProvider = MockProcessCameraProvider();
     const int cameraId = 10;
     const CameraLensDirection testLensDirection = CameraLensDirection.back;
     const int testSensorOrientation = 90;
     const CameraDescription testCameraDescription = CameraDescription(
         name: 'cameraName',
         lensDirection: testLensDirection,
         sensorOrientation: testSensorOrientation);
     const ResolutionPreset testResolutionPreset = ResolutionPreset.veryHigh;
     const bool enableAudio = true;
     const int resolutionWidth = 350;
     const int resolutionHeight = 750;
     final Camera mockCamera = MockCamera();
     final ResolutionInfo testResolutionInfo =
         ResolutionInfo(width: resolutionWidth, height: resolutionHeight);

     // TODO(camsim99): Modify this when camera configuration is supported and
     // defualt values no longer being used.
     // https://github.com/flutter/flutter/issues/120468
     // https://github.com/flutter/flutter/issues/120467
     final CameraInitializedEvent testCameraInitializedEvent =
         CameraInitializedEvent(
             cameraId,
             resolutionWidth.toDouble(),
             resolutionHeight.toDouble(),
             ExposureMode.auto,
             false,
             FocusMode.auto,
             false);

     // Call createCamera.
     when(camera.testPreview.setSurfaceProvider())
         .thenAnswer((_) async => cameraId);
     await camera.createCamera(testCameraDescription, testResolutionPreset,
         enableAudio: enableAudio);

     when(camera.processCameraProvider!.bindToLifecycle(
             camera.cameraSelector!, <UseCase>[camera.testPreview]))
         .thenAnswer((_) async => mockCamera);
     when(camera.testPreview.getResolutionInfo())
         .thenAnswer((_) async => testResolutionInfo);

     // Start listening to camera events stream to verify the proper CameraInitializedEvent is sent.
     camera.cameraEventStreamController.stream.listen((CameraEvent event) {
       expect(event, const TypeMatcher<CameraInitializedEvent>());
       expect(event, equals(testCameraInitializedEvent));
     });

     await camera.initializeCamera(cameraId);

     // Verify preview was bound and unbound to get preview resolution information.
     verify(camera.processCameraProvider!.bindToLifecycle(
         camera.cameraSelector!, <UseCase>[camera.testPreview]));
     verify(camera.processCameraProvider!.unbind(<UseCase>[camera.testPreview]));

     // Check camera instance was received, but preview is no longer bound.
     expect(camera.camera, equals(mockCamera));
     expect(camera.previewIsBound, isFalse);
   });

   test('dispose releases Flutter surface texture and unbinds all use cases',
       () async {
     final AndroidCameraCameraX camera = AndroidCameraCameraX();

     camera.preview = MockPreview();
     camera.processCameraProvider = MockProcessCameraProvider();

     camera.dispose(3);

     verify(camera.preview!.releaseFlutterSurfaceTexture());
     verify(camera.processCameraProvider!.unbindAll());
   });

   test('onCameraInitialized stream emits CameraInitializedEvents', () async {
     final AndroidCameraCameraX camera = AndroidCameraCameraX();
     const int cameraId = 16;
     final Stream<CameraInitializedEvent> eventStream =
         camera.onCameraInitialized(cameraId);
     final StreamQueue<CameraInitializedEvent> streamQueue =
         StreamQueue<CameraInitializedEvent>(eventStream);
     const CameraInitializedEvent testEvent = CameraInitializedEvent(
         cameraId, 320, 80, ExposureMode.auto, false, FocusMode.auto, false);

     camera.cameraEventStreamController.add(testEvent);

     expect(await streamQueue.next, testEvent);
     await streamQueue.cancel();
   });

   test('onCameraError stream emits errors caught by system services', () async {
     final AndroidCameraCameraX camera = AndroidCameraCameraX();
     const int cameraId = 27;
     const String testErrorDescription = 'Test error description!';
     final Stream<CameraErrorEvent> eventStream = camera.onCameraError(cameraId);
     final StreamQueue<CameraErrorEvent> streamQueue =
         StreamQueue<CameraErrorEvent>(eventStream);

     SystemServices.cameraErrorStreamController.add(testErrorDescription);

     expect(await streamQueue.next,
         equals(const CameraErrorEvent(cameraId, testErrorDescription)));
     await streamQueue.cancel();
   });

   test(
       'onDeviceOrientationChanged stream emits changes in device oreintation detected by system services',
       () async {
     final AndroidCameraCameraX camera = AndroidCameraCameraX();
     final Stream<DeviceOrientationChangedEvent> eventStream =
         camera.onDeviceOrientationChanged();
     final StreamQueue<DeviceOrientationChangedEvent> streamQueue =
         StreamQueue<DeviceOrientationChangedEvent>(eventStream);
     const DeviceOrientationChangedEvent testEvent =
         DeviceOrientationChangedEvent(DeviceOrientation.portraitDown);

     SystemServices.deviceOrientationChangedStreamController.add(testEvent);

     expect(await streamQueue.next, testEvent);
     await streamQueue.cancel();
   });

   test(
       'pausePreview unbinds preview from lifecycle when preview is nonnull and has been bound to lifecycle',
       () async {
     final AndroidCameraCameraX camera = AndroidCameraCameraX();

     camera.processCameraProvider = MockProcessCameraProvider();
     camera.preview = MockPreview();
     camera.previewIsBound = true;

     await camera.pausePreview(579);

     verify(camera.processCameraProvider!.unbind(<UseCase>[camera.preview!]));
     expect(camera.previewIsBound, isFalse);
   });

   test(
       'pausePreview does not unbind preview from lifecycle when preview has not been bound to lifecycle',
       () async {
     final AndroidCameraCameraX camera = AndroidCameraCameraX();

     camera.processCameraProvider = MockProcessCameraProvider();
     camera.preview = MockPreview();

     await camera.pausePreview(632);

     verifyNever(
         camera.processCameraProvider!.unbind(<UseCase>[camera.preview!]));
   });

   test('resumePreview does not bind preview to lifecycle if already bound',
       () async {
     final AndroidCameraCameraX camera = AndroidCameraCameraX();

     camera.processCameraProvider = MockProcessCameraProvider();
     camera.cameraSelector = MockCameraSelector();
     camera.preview = MockPreview();
     camera.previewIsBound = true;

     await camera.resumePreview(78);

     verifyNever(camera.processCameraProvider!
         .bindToLifecycle(camera.cameraSelector!, <UseCase>[camera.preview!]));
   });

   test('resumePreview binds preview to lifecycle if not already bound',
       () async {
     final AndroidCameraCameraX camera = AndroidCameraCameraX();

     camera.processCameraProvider = MockProcessCameraProvider();
     camera.cameraSelector = MockCameraSelector();
     camera.preview = MockPreview();

     await camera.resumePreview(78);

     verify(camera.processCameraProvider!
         .bindToLifecycle(camera.cameraSelector!, <UseCase>[camera.preview!]));
   });

   test(
       'buildPreview returns a FutureBuilder that does not return a Texture until the preview is bound to the lifecycle',
       () async {
     final AndroidCameraCameraX camera = AndroidCameraCameraX();
     const int textureId = 75;

     camera.processCameraProvider = MockProcessCameraProvider();
     camera.cameraSelector = MockCameraSelector();
     camera.preview = MockPreview();

     final FutureBuilder<void> previewWidget =
         camera.buildPreview(textureId) as FutureBuilder<void>;

     expect(
         previewWidget.builder(
             MockBuildContext(), const AsyncSnapshot<void>.nothing()),
         isA<SizedBox>());
     expect(
         previewWidget.builder(
             MockBuildContext(), const AsyncSnapshot<void>.waiting()),
         isA<SizedBox>());
     expect(
         previewWidget.builder(MockBuildContext(),
             const AsyncSnapshot<void>.withData(ConnectionState.active, null)),
         isA<SizedBox>());
   });

   test(
       'buildPreview returns a FutureBuilder that returns a Texture once the preview is bound to the lifecycle',
       () async {
     final AndroidCameraCameraX camera = AndroidCameraCameraX();
     const int textureId = 75;

     camera.processCameraProvider = MockProcessCameraProvider();
     camera.cameraSelector = MockCameraSelector();
     camera.preview = MockPreview();

     final FutureBuilder<void> previewWidget =
         camera.buildPreview(textureId) as FutureBuilder<void>;

     final Texture previewTexture = previewWidget.builder(MockBuildContext(),
             const AsyncSnapshot<void>.withData(ConnectionState.done, null))
         as Texture;
     expect(previewTexture.textureId, equals(textureId));
   });
 }

 /// Mock of [AndroidCameraCameraX] that stubs behavior of some methods for
 /// testing.
 class MockAndroidCameraCamerax extends AndroidCameraCameraX {
   bool cameraPermissionsRequested = false;
   bool startedListeningForDeviceOrientationChanges = false;
   final MockPreview testPreview = MockPreview();
   final MockCameraSelector mockBackCameraSelector = MockCameraSelector();
   final MockCameraSelector mockFrontCameraSelector = MockCameraSelector();

   @override
   Future<void> requestCameraPermissions(bool enableAudio) async {
     cameraPermissionsRequested = true;
   }

   @override
   void startListeningForDeviceOrientationChange(
       bool cameraIsFrontFacing, int sensorOrientation) {
     startedListeningForDeviceOrientationChanges = true;
     return;
   }

   @override
   CameraSelector createCameraSelector(int cameraSelectorLensDirection) {
     switch (cameraSelectorLensDirection) {
       case CameraSelector.lensFacingFront:
         return mockFrontCameraSelector;
       case CameraSelector.lensFacingBack:
       default:
         return mockBackCameraSelector;
     }
   }

   @override
   Preview createPreview(int targetRotation, ResolutionInfo? targetResolution) {
     return testPreview;
   }
 }
	// Copyright 2013 The Flutter Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	import 'dart:async';

	import 'package:async/async.dart';
	import 'package:camera_android_camerax/camera_android_camerax.dart';
	import 'package:camera_android_camerax/src/camera.dart';
	import 'package:camera_android_camerax/src/camera_info.dart';
	import 'package:camera_android_camerax/src/camera_selector.dart';
	import 'package:camera_android_camerax/src/camerax_library.g.dart';
	import 'package:camera_android_camerax/src/preview.dart';
	import 'package:camera_android_camerax/src/process_camera_provider.dart';
	import 'package:camera_android_camerax/src/system_services.dart';
	import 'package:camera_android_camerax/src/use_case.dart';
	import 'package:camera_platform_interface/camera_platform_interface.dart';
	import 'package:flutter/services.dart' show DeviceOrientation;
	import 'package:flutter/widgets.dart';
	import 'package:flutter_test/flutter_test.dart';
	import 'package:mockito/annotations.dart';
	import 'package:mockito/mockito.dart';

	import 'android_camera_camerax_test.mocks.dart';

	@GenerateNiceMocks(<MockSpec<Object>>[
	MockSpec<Camera>(),
	MockSpec<CameraInfo>(),
	MockSpec<CameraSelector>(),
	MockSpec<Preview>(),
	MockSpec<ProcessCameraProvider>(),
	])
	@GenerateMocks(<Type>[BuildContext])
	void main() {
	TestWidgetsFlutterBinding.ensureInitialized();

	test('Should fetch CameraDescription instances for available cameras',
	() async {
	// Arrange
	final MockAndroidCameraCamerax camera = MockAndroidCameraCamerax();
	camera.processCameraProvider = MockProcessCameraProvider();
	final List<dynamic> returnData = <dynamic>[
	<String, dynamic>{
	'name': 'Camera 0',
	'lensFacing': 'back',
	'sensorOrientation': 0
	},
	<String, dynamic>{
	'name': 'Camera 1',
	'lensFacing': 'front',
	'sensorOrientation': 90
	}
	];

	// Create mocks to use
	final MockCameraInfo mockFrontCameraInfo = MockCameraInfo();
	final MockCameraInfo mockBackCameraInfo = MockCameraInfo();

	// Mock calls to native platform
	when(camera.processCameraProvider!.getAvailableCameraInfos()).thenAnswer(
	(_) async => <MockCameraInfo>[mockBackCameraInfo, mockFrontCameraInfo]);
	when(camera.mockBackCameraSelector
	.filter(<MockCameraInfo>[mockFrontCameraInfo]))
	.thenAnswer((_) async => <MockCameraInfo>[]);
	when(camera.mockBackCameraSelector
	.filter(<MockCameraInfo>[mockBackCameraInfo]))
	.thenAnswer((_) async => <MockCameraInfo>[mockBackCameraInfo]);
	when(camera.mockFrontCameraSelector
	.filter(<MockCameraInfo>[mockBackCameraInfo]))
	.thenAnswer((_) async => <MockCameraInfo>[]);
	when(camera.mockFrontCameraSelector
	.filter(<MockCameraInfo>[mockFrontCameraInfo]))
	.thenAnswer((_) async => <MockCameraInfo>[mockFrontCameraInfo]);
	when(mockBackCameraInfo.getSensorRotationDegrees())
	.thenAnswer((_) async => 0);
	when(mockFrontCameraInfo.getSensorRotationDegrees())
	.thenAnswer((_) async => 90);

	final List<CameraDescription> cameraDescriptions =
	await camera.availableCameras();

	expect(cameraDescriptions.length, returnData.length);
	for (int i = 0; i < returnData.length; i++) {
	final Map<String, Object?> typedData =
	(returnData[i] as Map<dynamic, dynamic>).cast<String, Object?>();
	final CameraDescription cameraDescription = CameraDescription(
	name: typedData['name']! as String,
	lensDirection: (typedData['lensFacing']! as String) == 'front'
	? CameraLensDirection.front
	: CameraLensDirection.back,
	sensorOrientation: typedData['sensorOrientation']! as int,
	);
	expect(cameraDescriptions[i], cameraDescription);
	}
	});

	test(
	'createCamera requests permissions, starts listening for device orientation changes, and returns flutter surface texture ID',
	() async {
	final MockAndroidCameraCamerax camera = MockAndroidCameraCamerax();
	camera.processCameraProvider = MockProcessCameraProvider();
	const CameraLensDirection testLensDirection = CameraLensDirection.back;
	const int testSensorOrientation = 90;
	const CameraDescription testCameraDescription = CameraDescription(
	name: 'cameraName',
	lensDirection: testLensDirection,
	sensorOrientation: testSensorOrientation);
	const ResolutionPreset testResolutionPreset = ResolutionPreset.veryHigh;
	const bool enableAudio = true;
	const int testSurfaceTextureId = 6;

	when(camera.testPreview.setSurfaceProvider())
	.thenAnswer((_) async => testSurfaceTextureId);

	expect(
	await camera.createCamera(testCameraDescription, testResolutionPreset,
	enableAudio: enableAudio),
	equals(testSurfaceTextureId));

	// Verify permissions are requested and the camera starts listening for device orientation changes.
	expect(camera.cameraPermissionsRequested, isTrue);
	expect(camera.startedListeningForDeviceOrientationChanges, isTrue);

	// Verify CameraSelector is set with appropriate lens direction.
	expect(camera.cameraSelector, equals(camera.mockBackCameraSelector));

	// Verify the camera's Preview instance is instantiated properly.
	expect(camera.preview, equals(camera.testPreview));

	// Verify the camera's Preview instance has its surface provider set.
	verify(camera.preview!.setSurfaceProvider());
	});

	test(
	'initializeCamera throws AssertionError when createCamera has not been called before initializedCamera',
	() async {
	final AndroidCameraCameraX camera = AndroidCameraCameraX();
	expect(() => camera.initializeCamera(3), throwsAssertionError);
	});

	test('initializeCamera sends expected CameraInitializedEvent', () async {
	final MockAndroidCameraCamerax camera = MockAndroidCameraCamerax();
	camera.processCameraProvider = MockProcessCameraProvider();
	const int cameraId = 10;
	const CameraLensDirection testLensDirection = CameraLensDirection.back;
	const int testSensorOrientation = 90;
	const CameraDescription testCameraDescription = CameraDescription(
	name: 'cameraName',
	lensDirection: testLensDirection,
	sensorOrientation: testSensorOrientation);
	const ResolutionPreset testResolutionPreset = ResolutionPreset.veryHigh;
	const bool enableAudio = true;
	const int resolutionWidth = 350;
	const int resolutionHeight = 750;
	final Camera mockCamera = MockCamera();
	final ResolutionInfo testResolutionInfo =
	ResolutionInfo(width: resolutionWidth, height: resolutionHeight);

	// TODO(camsim99): Modify this when camera configuration is supported and
	// defualt values no longer being used.
	// https://github.com/flutter/flutter/issues/120468
	// https://github.com/flutter/flutter/issues/120467
	final CameraInitializedEvent testCameraInitializedEvent =
	CameraInitializedEvent(
	cameraId,
	resolutionWidth.toDouble(),
	resolutionHeight.toDouble(),
	ExposureMode.auto,
	false,
	FocusMode.auto,
	false);

	// Call createCamera.
	when(camera.testPreview.setSurfaceProvider())
	.thenAnswer((_) async => cameraId);
	await camera.createCamera(testCameraDescription, testResolutionPreset,
	enableAudio: enableAudio);

	when(camera.processCameraProvider!.bindToLifecycle(
	camera.cameraSelector!, <UseCase>[camera.testPreview]))
	.thenAnswer((_) async => mockCamera);
	when(camera.testPreview.getResolutionInfo())
	.thenAnswer((_) async => testResolutionInfo);

	// Start listening to camera events stream to verify the proper CameraInitializedEvent is sent.
	camera.cameraEventStreamController.stream.listen((CameraEvent event) {
	expect(event, const TypeMatcher<CameraInitializedEvent>());
	expect(event, equals(testCameraInitializedEvent));
	});

	await camera.initializeCamera(cameraId);

	// Verify preview was bound and unbound to get preview resolution information.
	verify(camera.processCameraProvider!.bindToLifecycle(
	camera.cameraSelector!, <UseCase>[camera.testPreview]));
	verify(camera.processCameraProvider!.unbind(<UseCase>[camera.testPreview]));

	// Check camera instance was received, but preview is no longer bound.
	expect(camera.camera, equals(mockCamera));
	expect(camera.previewIsBound, isFalse);
	});

	test('dispose releases Flutter surface texture and unbinds all use cases',
	() async {
	final AndroidCameraCameraX camera = AndroidCameraCameraX();

	camera.preview = MockPreview();
	camera.processCameraProvider = MockProcessCameraProvider();

	camera.dispose(3);

	verify(camera.preview!.releaseFlutterSurfaceTexture());
	verify(camera.processCameraProvider!.unbindAll());
	});

	test('onCameraInitialized stream emits CameraInitializedEvents', () async {
	final AndroidCameraCameraX camera = AndroidCameraCameraX();
	const int cameraId = 16;
	final Stream<CameraInitializedEvent> eventStream =
	camera.onCameraInitialized(cameraId);
	final StreamQueue<CameraInitializedEvent> streamQueue =
	StreamQueue<CameraInitializedEvent>(eventStream);
	const CameraInitializedEvent testEvent = CameraInitializedEvent(
	cameraId, 320, 80, ExposureMode.auto, false, FocusMode.auto, false);

	camera.cameraEventStreamController.add(testEvent);

	expect(await streamQueue.next, testEvent);
	await streamQueue.cancel();
	});

	test('onCameraError stream emits errors caught by system services', () async {
	final AndroidCameraCameraX camera = AndroidCameraCameraX();
	const int cameraId = 27;
	const String testErrorDescription = 'Test error description!';
	final Stream<CameraErrorEvent> eventStream = camera.onCameraError(cameraId);
	final StreamQueue<CameraErrorEvent> streamQueue =
	StreamQueue<CameraErrorEvent>(eventStream);

	SystemServices.cameraErrorStreamController.add(testErrorDescription);

	expect(await streamQueue.next,
	equals(const CameraErrorEvent(cameraId, testErrorDescription)));
	await streamQueue.cancel();
	});

	test(
	'onDeviceOrientationChanged stream emits changes in device oreintation detected by system services',
	() async {
	final AndroidCameraCameraX camera = AndroidCameraCameraX();
	final Stream<DeviceOrientationChangedEvent> eventStream =
	camera.onDeviceOrientationChanged();
	final StreamQueue<DeviceOrientationChangedEvent> streamQueue =
	StreamQueue<DeviceOrientationChangedEvent>(eventStream);
	const DeviceOrientationChangedEvent testEvent =
	DeviceOrientationChangedEvent(DeviceOrientation.portraitDown);

	SystemServices.deviceOrientationChangedStreamController.add(testEvent);

	expect(await streamQueue.next, testEvent);
	await streamQueue.cancel();
	});

	test(
	'pausePreview unbinds preview from lifecycle when preview is nonnull and has been bound to lifecycle',
	() async {
	final AndroidCameraCameraX camera = AndroidCameraCameraX();

	camera.processCameraProvider = MockProcessCameraProvider();
	camera.preview = MockPreview();
	camera.previewIsBound = true;

	await camera.pausePreview(579);

	verify(camera.processCameraProvider!.unbind(<UseCase>[camera.preview!]));
	expect(camera.previewIsBound, isFalse);
	});

	test(
	'pausePreview does not unbind preview from lifecycle when preview has not been bound to lifecycle',
	() async {
	final AndroidCameraCameraX camera = AndroidCameraCameraX();

	camera.processCameraProvider = MockProcessCameraProvider();
	camera.preview = MockPreview();

	await camera.pausePreview(632);

	verifyNever(
	camera.processCameraProvider!.unbind(<UseCase>[camera.preview!]));
	});

	test('resumePreview does not bind preview to lifecycle if already bound',
	() async {
	final AndroidCameraCameraX camera = AndroidCameraCameraX();

	camera.processCameraProvider = MockProcessCameraProvider();
	camera.cameraSelector = MockCameraSelector();
	camera.preview = MockPreview();
	camera.previewIsBound = true;

	await camera.resumePreview(78);

	verifyNever(camera.processCameraProvider!
	.bindToLifecycle(camera.cameraSelector!, <UseCase>[camera.preview!]));
	});

	test('resumePreview binds preview to lifecycle if not already bound',
	() async {
	final AndroidCameraCameraX camera = AndroidCameraCameraX();

	camera.processCameraProvider = MockProcessCameraProvider();
	camera.cameraSelector = MockCameraSelector();
	camera.preview = MockPreview();

	await camera.resumePreview(78);

	verify(camera.processCameraProvider!
	.bindToLifecycle(camera.cameraSelector!, <UseCase>[camera.preview!]));
	});

	test(
	'buildPreview returns a FutureBuilder that does not return a Texture until the preview is bound to the lifecycle',
	() async {
	final AndroidCameraCameraX camera = AndroidCameraCameraX();
	const int textureId = 75;

	camera.processCameraProvider = MockProcessCameraProvider();
	camera.cameraSelector = MockCameraSelector();
	camera.preview = MockPreview();

	final FutureBuilder<void> previewWidget =
	camera.buildPreview(textureId) as FutureBuilder<void>;

	expect(
	previewWidget.builder(
	MockBuildContext(), const AsyncSnapshot<void>.nothing()),
	isA<SizedBox>());
	expect(
	previewWidget.builder(
	MockBuildContext(), const AsyncSnapshot<void>.waiting()),
	isA<SizedBox>());
	expect(
	previewWidget.builder(MockBuildContext(),
	const AsyncSnapshot<void>.withData(ConnectionState.active, null)),
	isA<SizedBox>());
	});

	test(
	'buildPreview returns a FutureBuilder that returns a Texture once the preview is bound to the lifecycle',
	() async {
	final AndroidCameraCameraX camera = AndroidCameraCameraX();
	const int textureId = 75;

	camera.processCameraProvider = MockProcessCameraProvider();
	camera.cameraSelector = MockCameraSelector();
	camera.preview = MockPreview();

	final FutureBuilder<void> previewWidget =
	camera.buildPreview(textureId) as FutureBuilder<void>;

	final Texture previewTexture = previewWidget.builder(MockBuildContext(),
	const AsyncSnapshot<void>.withData(ConnectionState.done, null))
	as Texture;
	expect(previewTexture.textureId, equals(textureId));
	});
	}

	/// Mock of [AndroidCameraCameraX] that stubs behavior of some methods for
	/// testing.
	class MockAndroidCameraCamerax extends AndroidCameraCameraX {
	bool cameraPermissionsRequested = false;
	bool startedListeningForDeviceOrientationChanges = false;
	final MockPreview testPreview = MockPreview();
	final MockCameraSelector mockBackCameraSelector = MockCameraSelector();
	final MockCameraSelector mockFrontCameraSelector = MockCameraSelector();

	@override
	Future<void> requestCameraPermissions(bool enableAudio) async {
	cameraPermissionsRequested = true;
	}

	@override
	void startListeningForDeviceOrientationChange(
	bool cameraIsFrontFacing, int sensorOrientation) {
	startedListeningForDeviceOrientationChanges = true;
	return;
	}

	@override
	CameraSelector createCameraSelector(int cameraSelectorLensDirection) {
	switch (cameraSelectorLensDirection) {
	case CameraSelector.lensFacingFront:
	return mockFrontCameraSelector;
	case CameraSelector.lensFacingBack:
	default:
	return mockBackCameraSelector;
	}
	}

	@override
	Preview createPreview(int targetRotation, ResolutionInfo? targetResolution) {
	return testPreview;
	}
	}