[camerax] Mock InstanceManager in unit tests (#4121)

Ensures that `InstanceManager` is mocked (once) for all `camera_android_camerax` tests.

Fixes https://github.com/flutter/flutter/issues/127661.

packages/camera/camera_android_camerax/test/analyzer_test.dart

@@ -16,18 +16,19 @@ import 'test_camerax_library.g.dart';
 void main() {
   TestWidgetsFlutterBinding.ensureInitialized();
 
+  // Mocks the call to clear the native InstanceManager.
+  TestInstanceManagerHostApi.setup(MockTestInstanceManagerHostApi());
+
   group('Analyzer', () {
     setUp(() {});
 
     tearDown(() {
       TestAnalyzerHostApi.setup(null);
-      TestInstanceManagerHostApi.setup(null);
     });
 
     test('HostApi create', () {
       final MockTestAnalyzerHostApi mockApi = MockTestAnalyzerHostApi();
       TestAnalyzerHostApi.setup(mockApi);
-      TestInstanceManagerHostApi.setup(MockTestInstanceManagerHostApi());
 
       final InstanceManager instanceManager = InstanceManager(
         onWeakReferenceRemoved: (_) {},

packages/camera/camera_android_camerax/test/android_camera_camerax_test.dart

@@ -98,9 +98,6 @@ void main() {
     return cameraClosingEventSent && cameraErrorSent;
   }
 
-  // Mocks the call to clear the native InstanceManager.
-  TestInstanceManagerHostApi.setup(MockTestInstanceManagerHostApi());
-
   test('Should fetch CameraDescription instances for available cameras',
       () async {
     // Arrange

packages/camera/camera_android_camerax/test/camera_state_error_test.dart

@@ -7,17 +7,17 @@ import 'package:camera_android_camerax/src/instance_manager.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:mockito/annotations.dart';
 
+import 'camera_state_error_test.mocks.dart';
 import 'test_camerax_library.g.dart';
 
 @GenerateMocks(<Type>[TestInstanceManagerHostApi])
 void main() {
   TestWidgetsFlutterBinding.ensureInitialized();
 
-  group('CameraStateError', () {
+  // Mocks the call to clear the native InstanceManager.
-    tearDown(() {
+  TestInstanceManagerHostApi.setup(MockTestInstanceManagerHostApi());
-      TestInstanceManagerHostApi.setup(null);
-    });
 
+  group('CameraStateError', () {
     test(
         'FlutterAPI create makes call to create CameraStateError instance with expected identifier',
         () {

packages/camera/camera_android_camerax/test/camera_state_test.dart

@@ -20,10 +20,6 @@ void main() {
   TestInstanceManagerHostApi.setup(MockTestInstanceManagerHostApi());
 
   group('CameraState', () {
-    tearDown(() {
-      TestInstanceManagerHostApi.setup(null);
-    });
-
     test(
         'FlutterAPI create makes call to create CameraState instance with expected identifier',
         () {

packages/camera/camera_android_camerax/test/image_analysis_test.dart

@@ -26,14 +26,12 @@ void main() {
 
     tearDown(() {
       TestImageAnalysisHostApi.setup(null);
-      TestInstanceManagerHostApi.setup(null);
     });
 
     test('HostApi create', () {
       final MockTestImageAnalysisHostApi mockApi =
           MockTestImageAnalysisHostApi();
       TestImageAnalysisHostApi.setup(mockApi);
-      TestInstanceManagerHostApi.setup(MockTestInstanceManagerHostApi());
 
       final InstanceManager instanceManager = InstanceManager(
         onWeakReferenceRemoved: (_) {},

packages/camera/camera_android_camerax/test/image_capture_test.dart

@@ -12,10 +12,13 @@ import 'package:mockito/mockito.dart';
 import 'image_capture_test.mocks.dart';
 import 'test_camerax_library.g.dart';
 
-@GenerateMocks(<Type>[TestImageCaptureHostApi])
+@GenerateMocks(<Type>[TestImageCaptureHostApi, TestInstanceManagerHostApi])
 void main() {
   TestWidgetsFlutterBinding.ensureInitialized();
 
+  // Mocks the call to clear the native InstanceManager.
+  TestInstanceManagerHostApi.setup(MockTestInstanceManagerHostApi());
+
   group('ImageCapture', () {
     tearDown(() => TestImageCaptureHostApi.setup(null));
 

packages/camera/camera_android_camerax/test/image_capture_test.mocks.dart

@@ -1,7 +1,9 @@
-// Mocks generated by Mockito 5.4.0 from annotations
+// Mocks generated by Mockito 5.4.1 from annotations
 // in camera_android_camerax/test/image_capture_test.dart.
 // Do not manually edit this file.
 
+// @dart=2.19
+
 // ignore_for_file: no_leading_underscores_for_library_prefixes
 import 'dart:async' as _i4;
 
@@ -71,3 +73,22 @@ class MockTestImageCaptureHostApi extends _i1.Mock
         returnValue: _i4.Future<String>.value(''),
       ) as _i4.Future<String>);
 }
+
+/// A class which mocks [TestInstanceManagerHostApi].
+///
+/// See the documentation for Mockito's code generation for more information.
+class MockTestInstanceManagerHostApi extends _i1.Mock
+    implements _i2.TestInstanceManagerHostApi {
+  MockTestInstanceManagerHostApi() {
+    _i1.throwOnMissingStub(this);
+  }
+
+  @override
+  void clear() => super.noSuchMethod(
+        Invocation.method(
+          #clear,
+          [],
+        ),
+        returnValueForMissingStub: null,
+      );
+}

packages/camera/camera_android_camerax/test/image_proxy_test.dart

@@ -22,11 +22,8 @@ void main() {
   TestInstanceManagerHostApi.setup(MockTestInstanceManagerHostApi());
 
   group('ImageProxy', () {
-    setUp(() {});
-
     tearDown(() {
       TestImageProxyHostApi.setup(null);
-      TestInstanceManagerHostApi.setup(null);
     });
 
     test('getPlanes', () async {

packages/camera/camera_android_camerax/test/live_data_test.dart

@@ -24,7 +24,6 @@ void main() {
   group('LiveData', () {
     tearDown(() {
       TestLiveDataHostApi.setup(null);
-      TestInstanceManagerHostApi.setup(null);
     });
 
     test('observe makes call to add observer to LiveData instance', () async {
@@ -103,7 +102,6 @@ void main() {
     test('getValue returns expected value', () async {
       final MockTestLiveDataHostApi mockApi = MockTestLiveDataHostApi();
       TestLiveDataHostApi.setup(mockApi);
-      TestInstanceManagerHostApi.setup(MockTestInstanceManagerHostApi());
 
       final InstanceManager instanceManager = InstanceManager(
         onWeakReferenceRemoved: (_) {},

packages/camera/camera_android_camerax/test/observer_test.dart

@@ -17,16 +17,17 @@ import 'test_camerax_library.g.dart';
 void main() {
   TestWidgetsFlutterBinding.ensureInitialized();
 
+  // Mocks the call to clear the native InstanceManager.
+  TestInstanceManagerHostApi.setup(MockTestInstanceManagerHostApi());
+
   group('Observer', () {
     tearDown(() {
       TestObserverHostApi.setup(null);
-      TestInstanceManagerHostApi.setup(null);
     });
 
     test('HostApi create makes call to create Observer instance', () {
       final MockTestObserverHostApi mockApi = MockTestObserverHostApi();
       TestObserverHostApi.setup(mockApi);
-      TestInstanceManagerHostApi.setup(MockTestInstanceManagerHostApi());
 
       final InstanceManager instanceManager = InstanceManager(
         onWeakReferenceRemoved: (_) {},
@@ -47,7 +48,6 @@ void main() {
         () {
       final MockTestObserverHostApi mockApi = MockTestObserverHostApi();
       TestObserverHostApi.setup(mockApi);
-      TestInstanceManagerHostApi.setup(MockTestInstanceManagerHostApi());
 
       final Observer<String> cameraStateObserver =
           Observer<String>.detached(onChanged: (Object value) {});

packages/camera/camera_android_camerax/test/plane_proxy_test.dart

@@ -20,12 +20,6 @@ void main() {
   TestInstanceManagerHostApi.setup(MockTestInstanceManagerHostApi());
 
   group('PlaneProxy', () {
-    setUp(() {});
-
-    tearDown(() {
-      TestInstanceManagerHostApi.setup(null);
-    });
-
     test('FlutterAPI create', () {
       final InstanceManager instanceManager = InstanceManager(
         onWeakReferenceRemoved: (_) {},

packages/camera/camera_android_camerax/test/zoom_state_test.dart

@@ -18,8 +18,6 @@ void main() {
   TestInstanceManagerHostApi.setup(MockTestInstanceManagerHostApi());
 
   group('ZoomState', () {
-    tearDown(() => TestInstanceManagerHostApi.setup(null));
-
     test('flutterApi create makes call to create expected ZoomState', () {
       final InstanceManager instanceManager = InstanceManager(
         onWeakReferenceRemoved: (_) {},