diff --git a/packages/amplify_datastore/lib/amplify_datastore.dart b/packages/amplify_datastore/lib/amplify_datastore.dart
index 95ebed3bc0..aece0b2bbb 100644
--- a/packages/amplify_datastore/lib/amplify_datastore.dart
+++ b/packages/amplify_datastore/lib/amplify_datastore.dart
@@ -106,7 +106,7 @@ class AmplifyDataStore extends DataStorePluginInterface
     if (apiPlugin != null && gqlConfig != null) {
       // ignore: invalid_use_of_protected_member
       final authProviders = apiPlugin.authProviders;
-      final nativePlugin = _NativeAmplifyApi(authProviders);
+      final nativePlugin = NativeAmplifyApi(authProviders);
       NativeApiPlugin.setup(nativePlugin);
 
       final nativeBridge = NativeApiBridge();
@@ -288,10 +288,11 @@ class _NativeAmplifyAuthCognito
   String get runtimeTypeName => '_NativeAmplifyAuthCognito';
 }
 
-class _NativeAmplifyApi
+@visibleForTesting
+class NativeAmplifyApi
     with AWSDebuggable, AmplifyLoggerMixin
     implements NativeApiPlugin {
-  _NativeAmplifyApi(this._authProviders);
+  NativeAmplifyApi(this._authProviders);
 
   /// The registered [APIAuthProvider] instances.
   final Map<APIAuthorizationType<AmplifyAuthProvider>, APIAuthProvider>
diff --git a/packages/amplify_datastore/lib/src/utils/native_api_helpers.dart b/packages/amplify_datastore/lib/src/utils/native_api_helpers.dart
index 9e1493176a..32eceac5eb 100644
--- a/packages/amplify_datastore/lib/src/utils/native_api_helpers.dart
+++ b/packages/amplify_datastore/lib/src/utils/native_api_helpers.dart
@@ -2,7 +2,6 @@ import 'dart:convert';
 
 import 'package:amplify_core/amplify_core.dart';
 import 'package:amplify_datastore/src/native_plugin.g.dart';
-import 'package:collection/collection.dart';
 
 /// Convert a [NativeGraphQLResponse] to a [GraphQLResponse]
 GraphQLRequest<String> nativeRequestToGraphQLRequest(
@@ -39,7 +38,7 @@ APIAuthorizationType? nativeToApiAuthorizationType(String? authMode) {
 NativeGraphQLResponse graphQLResponseToNativeResponse(
     GraphQLResponse<String> response) {
   final errorJson = jsonEncode(
-      response.errors.whereNotNull().map((e) => e.toJson()).toList());
+      response.errors.map((e) => e.toJson()).toList());
   return NativeGraphQLResponse(
     payloadJson: response.data,
     errorsJson: errorJson,
diff --git a/packages/amplify_datastore/test/native_amplify_api_test.dart b/packages/amplify_datastore/test/native_amplify_api_test.dart
new file mode 100644
index 0000000000..546e602f18
--- /dev/null
+++ b/packages/amplify_datastore/test/native_amplify_api_test.dart
@@ -0,0 +1,791 @@
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+import 'dart:async';
+
+import 'package:amplify_core/amplify_core.dart';
+import 'package:amplify_datastore/amplify_datastore.dart';
+import 'package:amplify_datastore/src/native_plugin.g.dart';
+import 'package:flutter/services.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() async {
+  TestWidgetsFlutterBinding binding =
+      TestWidgetsFlutterBinding.ensureInitialized();
+
+  BasicMessageChannel<Object?> channel = BasicMessageChannel<Object?>(
+    'dev.flutter.pigeon.amplify_datastore.NativeApiBridge.sendSubscriptionEvent',
+    MockNativeAuthBridgeCodec(),
+  );
+
+  MockAPIPlugin<String> mockAPIPlugin = MockAPIPlugin<String>();
+
+  setUp(() async {
+    mockAPIPlugin.clear();
+
+    await Amplify.API.addPlugin(
+      mockAPIPlugin,
+      authProviderRepo: AmplifyAuthProviderRepository(),
+    );
+
+    binding.defaultBinaryMessenger.setMockDecodedMessageHandler<Object?>(
+      channel,
+      null,
+    );
+  });
+
+  tearDown(() async {
+    await Amplify.reset();
+  });
+
+  group('NativeAmplifyAPI', () {
+    group('Query', () {
+      test('Empty Request/Response', () async {
+        String document = '';
+        Map<String, dynamic> emptyMap = {};
+        String emptyJsonArray = '[]';
+
+        mockAPIPlugin.queryMethod = <String>(GraphQLRequest mockRequest) {
+          expect(mockRequest.document, document);
+          expect(mockRequest.variables, emptyMap);
+          expect(mockRequest.apiName, null);
+          expect(mockRequest.authorizationMode, null);
+          expect(mockRequest.headers, null);
+          expect(mockRequest.decodePath, null);
+          expect(mockRequest.modelType, null);
+
+          return GraphQLOperation<String>(
+            CancelableOperation<GraphQLResponse<String>>.fromValue(
+              GraphQLResponse<String>(
+                data: null as String?,
+                errors: [],
+              ),
+            ),
+          );
+        };
+
+        NativeAmplifyApi nativeAmplifyApi = NativeAmplifyApi({});
+
+        NativeGraphQLRequest request = NativeGraphQLRequest(document: '');
+        NativeGraphQLResponse response = await nativeAmplifyApi.query(request);
+
+        expect(response.payloadJson, null);
+        expect(response.errorsJson, emptyJsonArray);
+      });
+
+      test('Filled Request/Response', () async {
+        String document = 'document';
+        String apiName = 'apiName';
+        String variable1Key = 'variable1';
+        int variable1Value = 1;
+        String variable2Key = 'variable2';
+        String variable2Value = 'test string';
+        String variablesJson =
+            '{"$variable1Key": $variable1Value, "$variable2Key": "$variable2Value"}';
+        String responseType = 'responseType';
+        String decodePath = 'decodePath';
+        String options = 'options';
+        String payloadJson = '{}';
+        String errorMessage1 = 'errorsJson1';
+        String errorMessage2 = 'errorsJson2';
+        String errorsJson =
+            '[{"message":"$errorMessage1"},{"message":"$errorMessage2"}]';
+        String authMode = 'apiKey';
+
+        mockAPIPlugin.queryMethod = <String>(GraphQLRequest mockRequest) {
+          expect(mockRequest.id.length, greaterThan(0));
+          expect(mockRequest.document, document);
+          expect(mockRequest.variables[variable1Key], variable1Value);
+          expect(mockRequest.variables[variable2Key], variable2Value);
+          expect(mockRequest.apiName, apiName);
+          expect(mockRequest.authorizationMode, APIAuthorizationType.apiKey);
+          expect(mockRequest.headers, null);
+          expect(mockRequest.decodePath, null);
+          expect(mockRequest.modelType, null);
+
+          return GraphQLOperation<String>(
+            CancelableOperation<GraphQLResponse<String>>.fromValue(
+              GraphQLResponse<String>(
+                data: payloadJson as String?,
+                errors: [
+                  GraphQLResponseError(message: errorMessage1),
+                  GraphQLResponseError(message: errorMessage2),
+                ],
+              ),
+            ),
+          );
+        };
+
+        NativeAmplifyApi nativeAmplifyApi = NativeAmplifyApi({});
+
+        NativeGraphQLRequest request = NativeGraphQLRequest(
+            document: document,
+            apiName: apiName,
+            variablesJson: variablesJson,
+            responseType: responseType,
+            decodePath: decodePath,
+            options: options,
+            authMode: authMode);
+        NativeGraphQLResponse response = await nativeAmplifyApi.query(request);
+
+        expect(response.payloadJson, payloadJson);
+        expect(response.errorsJson, errorsJson);
+      });
+
+      Future<void> _authModeExpectHelepr(
+        String? authMode,
+        APIAuthorizationType? expected,
+      ) async {
+        mockAPIPlugin.queryMethod = <String>(GraphQLRequest mockRequest) {
+          expect(mockRequest.authorizationMode, expected);
+
+          return GraphQLOperation<String>(
+            CancelableOperation<GraphQLResponse<String>>.fromValue(
+              GraphQLResponse<String>(
+                data: null as String?,
+                errors: [],
+              ),
+            ),
+          );
+        };
+
+        NativeAmplifyApi nativeAmplifyApi = NativeAmplifyApi({});
+        await nativeAmplifyApi.query(
+          NativeGraphQLRequest(
+            document: '',
+            authMode: authMode,
+          ),
+        );
+      }
+
+      test('AuthModeTypes', () async {
+        await _authModeExpectHelepr('apiKey', APIAuthorizationType.apiKey);
+        await _authModeExpectHelepr('awsIAM', APIAuthorizationType.iam);
+        await _authModeExpectHelepr('openIDConnect', APIAuthorizationType.oidc);
+        await _authModeExpectHelepr('amazonCognitoUserPools', APIAuthorizationType.userPools);
+        await _authModeExpectHelepr('function', APIAuthorizationType.function);
+        await _authModeExpectHelepr('none', APIAuthorizationType.none);
+        await _authModeExpectHelepr(null, null);
+      });
+
+      test('Invalid Request Variables Json Exception', () async {
+        String document = '';
+        String invalidJson = 'INVALID JSON';
+
+        NativeAmplifyApi nativeAmplifyApi = NativeAmplifyApi({});
+
+        NativeGraphQLRequest request = NativeGraphQLRequest(
+          document: document,
+          variablesJson: invalidJson,
+        );
+
+        expect(() async => await nativeAmplifyApi.query(request),
+            throwsA(TypeMatcher<FormatException>()));
+      });
+
+      test('API Exception', () async {
+        String exceptionMessage = 'API Exception';
+
+        mockAPIPlugin.queryMethod = <String>(GraphQLRequest mockRequest) {
+          throw NetworkException(exceptionMessage);
+        };
+
+        NativeAmplifyApi nativeAmplifyApi = NativeAmplifyApi({});
+
+        NativeGraphQLRequest request = NativeGraphQLRequest(
+          document: '',
+        );
+
+        expect(
+          () async => await nativeAmplifyApi.query(request),
+          throwsA(
+            predicate(
+                (e) => e is NetworkException && e.message == exceptionMessage),
+          ),
+        );
+      });
+    });
+
+    group('Mutate', () {
+      test('Empty Request/Response', () async {
+        String document = '';
+        Map<String, dynamic> emptyMap = {};
+        String emptyJsonArray = '[]';
+
+        mockAPIPlugin.mutateMethod = <String>(GraphQLRequest mockRequest) {
+          expect(mockRequest.document, document);
+          expect(mockRequest.variables, emptyMap);
+          expect(mockRequest.apiName, null);
+          expect(mockRequest.authorizationMode, null);
+          expect(mockRequest.headers, null);
+          expect(mockRequest.decodePath, null);
+          expect(mockRequest.modelType, null);
+
+          return GraphQLOperation<String>(
+            CancelableOperation<GraphQLResponse<String>>.fromValue(
+              GraphQLResponse<String>(
+                data: null as String?,
+                errors: [],
+              ),
+            ),
+          );
+        };
+
+        NativeAmplifyApi nativeAmplifyApi = NativeAmplifyApi({});
+
+        NativeGraphQLRequest request = NativeGraphQLRequest(document: document);
+        NativeGraphQLResponse response = await nativeAmplifyApi.mutate(request);
+
+        expect(response.payloadJson, null);
+        expect(response.errorsJson, emptyJsonArray);
+      });
+
+      test('Filled Request/Response', () async {
+        String document = 'document';
+        String apiName = 'apiName';
+        String authMode = 'apiKey';
+        String variable1Key = 'variable1';
+        int variable1Value = 1;
+        String variable2Key = 'variable2';
+        String variable2Value = 'test string';
+        String variablesJson =
+            '{"$variable1Key": $variable1Value, "$variable2Key": "$variable2Value"}';
+        String responseType = 'responseType';
+        String decodePath = 'decodePath';
+        String options = 'options';
+        String payloadJson = '{}';
+        String errorMessage1 = 'errorsJson1';
+        String errorMessage2 = 'errorsJson2';
+        String errorsJson =
+            '[{"message":"$errorMessage1"},{"message":"$errorMessage2"}]';
+
+        mockAPIPlugin.mutateMethod = <String>(GraphQLRequest mockRequest) {
+          expect(mockRequest.id.length, greaterThan(0));
+          expect(mockRequest.document, document);
+          expect(mockRequest.variables[variable1Key], variable1Value);
+          expect(mockRequest.variables[variable2Key], variable2Value);
+          expect(mockRequest.apiName, apiName);
+          expect(mockRequest.authorizationMode, APIAuthorizationType.apiKey);
+          expect(mockRequest.headers, null);
+          expect(mockRequest.decodePath, null);
+          expect(mockRequest.modelType, null);
+
+          return GraphQLOperation<String>(
+            CancelableOperation<GraphQLResponse<String>>.fromValue(
+              GraphQLResponse<String>(
+                data: payloadJson as String?,
+                errors: [
+                  GraphQLResponseError(message: errorMessage1),
+                  GraphQLResponseError(message: errorMessage2),
+                ],
+              ),
+            ),
+          );
+        };
+
+        NativeAmplifyApi nativeAmplifyApi = NativeAmplifyApi({});
+
+        NativeGraphQLRequest request = NativeGraphQLRequest(
+          document: document,
+          apiName: apiName,
+          authMode: authMode,
+          variablesJson: variablesJson,
+          responseType: responseType,
+          decodePath: decodePath,
+          options: options,
+        );
+        NativeGraphQLResponse response = await nativeAmplifyApi.mutate(request);
+
+        expect(response.payloadJson, payloadJson);
+        expect(response.errorsJson, errorsJson);
+      });
+
+      test('Invalid Request Variables Json Exception', () async {
+        String document = '';
+        String invalidJson = 'INVALID JSON';
+
+        NativeAmplifyApi nativeAmplifyApi = NativeAmplifyApi({});
+
+        NativeGraphQLRequest request = NativeGraphQLRequest(
+          document: document,
+          variablesJson: invalidJson,
+        );
+
+        expect(() async => await nativeAmplifyApi.mutate(request),
+            throwsA(TypeMatcher<FormatException>()));
+      });
+
+      test('API Exception', () async {
+        String exceptionMessage = 'API Exception';
+
+        mockAPIPlugin.mutateMethod = <String>(GraphQLRequest mockRequest) {
+          throw NetworkException(exceptionMessage);
+        };
+
+        NativeAmplifyApi nativeAmplifyApi = NativeAmplifyApi({});
+
+        NativeGraphQLRequest request = NativeGraphQLRequest(
+          document: '',
+        );
+
+        expect(
+          () async => await nativeAmplifyApi.mutate(request),
+          throwsA(
+            predicate(
+                (e) => e is NetworkException && e.message == 'API Exception'),
+          ),
+        );
+      });
+    });
+
+    group('Subscribe', () {
+      test('Empty Request/Response', () async {
+        String responseType = 'connecting';
+        String document = '';
+        Map<String, dynamic> emptyMap = {};
+
+        mockAPIPlugin.subscribeMethod = <String>(
+          GraphQLRequest mockRequest,
+          void Function()? onEstablished,
+        ) {
+          expect(mockRequest.document, document);
+          expect(mockRequest.variables, emptyMap);
+          expect(mockRequest.apiName, null);
+          expect(mockRequest.authorizationMode, null);
+          expect(mockRequest.headers, null);
+          expect(mockRequest.decodePath, null);
+          expect(mockRequest.modelType, null);
+
+          var controller = StreamController<GraphQLResponse<String>>();
+          return controller.stream;
+        };
+
+        NativeAmplifyApi nativeAmplifyApi = NativeAmplifyApi({});
+
+        NativeGraphQLRequest request = NativeGraphQLRequest(document: document);
+        NativeGraphQLSubscriptionResponse response =
+            await nativeAmplifyApi.subscribe(request);
+
+        expect(response.payloadJson, null);
+        expect(response.subscriptionId.length, greaterThan(0));
+        expect(response.type, responseType);
+      });
+
+      test('Filled Request/Response', () async {
+        String responseType = 'connecting';
+        String document = 'document';
+        String apiName = 'apiName';
+        String authMode = 'apiKey';
+        String variable1Key = 'variable1';
+        int variable1Value = 1;
+        String variable2Key = 'variable2';
+        String variable2Value = 'test string';
+        String variablesJson =
+            '{"$variable1Key": $variable1Value, "$variable2Key": "$variable2Value"}';
+        String decodePath = 'decodePath';
+        String options = 'options';
+
+        mockAPIPlugin.subscribeMethod = <String>(
+          GraphQLRequest mockRequest,
+          void Function()? onEstablished,
+        ) {
+          expect(mockRequest.id.length, greaterThan(0));
+          expect(mockRequest.document, document);
+          expect(mockRequest.variables[variable1Key], variable1Value);
+          expect(mockRequest.variables[variable2Key], variable2Value);
+          expect(mockRequest.apiName, apiName);
+          expect(mockRequest.authorizationMode, APIAuthorizationType.apiKey);
+          expect(mockRequest.headers, null);
+          expect(mockRequest.decodePath, null);
+          expect(mockRequest.modelType, null);
+
+          var controller = StreamController<GraphQLResponse<String>>();
+          return controller.stream;
+        };
+
+        NativeAmplifyApi nativeAmplifyApi = NativeAmplifyApi({});
+
+        NativeGraphQLRequest request = NativeGraphQLRequest(
+          document: document,
+          apiName: apiName,
+          authMode: authMode,
+          variablesJson: variablesJson,
+          responseType: responseType,
+          decodePath: decodePath,
+          options: options,
+        );
+        NativeGraphQLSubscriptionResponse response =
+            await nativeAmplifyApi.subscribe(request);
+
+        expect(response.payloadJson, null);
+        expect(response.subscriptionId.length, greaterThan(0));
+        expect(response.type, responseType);
+      });
+
+      test('Invalid Request Variables Json Exception', () async {
+        String document = '';
+        String invalidJson = 'INVALID JSON';
+
+        NativeAmplifyApi nativeAmplifyApi = NativeAmplifyApi({});
+
+        NativeGraphQLRequest request = NativeGraphQLRequest(
+          document: document,
+          variablesJson: invalidJson,
+        );
+
+        expect(() async => await nativeAmplifyApi.subscribe(request),
+            throwsA(TypeMatcher<FormatException>()));
+      });
+
+      test('API Exception', () async {
+        String exceptionMessage = 'API Exception';
+
+        mockAPIPlugin.subscribeMethod = <String>(
+          GraphQLRequest mockRequest,
+          void Function()? onEstablished,
+        ) {
+          throw NetworkException(exceptionMessage);
+        };
+
+        NativeAmplifyApi nativeAmplifyApi = NativeAmplifyApi({});
+
+        NativeGraphQLRequest request = NativeGraphQLRequest(
+          document: '',
+        );
+
+        expect(
+          () async => await nativeAmplifyApi.subscribe(request),
+          throwsA(
+            predicate(
+                (e) => e is NetworkException && e.message == 'API Exception'),
+          ),
+        );
+      });
+
+      test('Established/Connected Callback', () async {
+        void Function()? onEstablishedCallback;
+
+        mockAPIPlugin.subscribeMethod = <String>(
+          GraphQLRequest mockRequest,
+          void Function()? onEstablished,
+        ) {
+          onEstablishedCallback = onEstablished;
+          var controller = StreamController<GraphQLResponse<String>>();
+          return controller.stream;
+        };
+
+        NativeAmplifyApi nativeAmplifyApi = NativeAmplifyApi({});
+
+        NativeGraphQLRequest request = NativeGraphQLRequest(
+          document: '',
+        );
+
+        await nativeAmplifyApi.subscribe(request);
+
+        binding.defaultBinaryMessenger.setMockDecodedMessageHandler<Object?>(
+          channel,
+          (Object? message) {
+            expect(message, isA<List>());
+            List responses = message as List;
+
+            expect(responses.length, greaterThan(0));
+            expect(responses[0], isA<NativeGraphQLSubscriptionResponse>());
+            NativeGraphQLSubscriptionResponse response = responses[0];
+
+            expect(response.payloadJson, null);
+            expect(response.subscriptionId.length, greaterThan(0));
+            expect(response.type, 'start_ack');
+
+            return Future.value(message);
+          },
+        );
+
+        expect(onEstablishedCallback, isNotNull);
+        expect(() => onEstablishedCallback?.call(), returnsNormally);
+      });
+
+      test('Send Data Event', () async {
+        String payloadJson = 'payloadJson';
+        StreamController? responseController;
+
+        mockAPIPlugin.subscribeMethod = <String>(
+          GraphQLRequest mockRequest,
+          void Function()? onEstablished,
+        ) {
+          var controller = StreamController<GraphQLResponse<String>>();
+          responseController = controller;
+          return controller.stream;
+        };
+
+        NativeAmplifyApi nativeAmplifyApi = NativeAmplifyApi({});
+
+        await nativeAmplifyApi.subscribe(
+          NativeGraphQLRequest(document: ''),
+        );
+
+        binding.defaultBinaryMessenger.setMockDecodedMessageHandler<Object?>(
+          channel,
+          (Object? message) {
+            expect(message, isA<List>());
+            List responses = message as List;
+
+            expect(responses.length, greaterThan(0));
+            expect(responses[0], isA<NativeGraphQLSubscriptionResponse>());
+            NativeGraphQLSubscriptionResponse response = responses[0];
+
+            expect(response.payloadJson, payloadJson);
+            expect(response.subscriptionId.length, greaterThan(0));
+            expect(response.type, 'data');
+
+            return Future.value(message);
+          },
+        );
+
+        expect(responseController, isNotNull);
+        expect(
+          () => responseController?.add(
+            GraphQLResponse<String>(
+              data: payloadJson,
+              errors: [],
+            ),
+          ),
+          returnsNormally,
+        );
+      });
+
+      test('Send Data With Errors Event', () async {
+        String payloadJson = 'payloadJson';
+        String errorMessage1 = 'errorsJson1';
+        String errorMessage2 = 'errorsJson2';
+        String errorsJson =
+            '{"errors":[{"message":"$errorMessage1"},{"message":"$errorMessage2"}]}';
+
+        StreamController? responseController;
+
+        mockAPIPlugin.subscribeMethod = <String>(
+          GraphQLRequest mockRequest,
+          void Function()? onEstablished,
+        ) {
+          var controller = StreamController<GraphQLResponse<String>>();
+          responseController = controller;
+          return controller.stream;
+        };
+
+        NativeAmplifyApi nativeAmplifyApi = NativeAmplifyApi({});
+
+        await nativeAmplifyApi.subscribe(
+          NativeGraphQLRequest(document: ''),
+        );
+
+        binding.defaultBinaryMessenger.setMockDecodedMessageHandler<Object?>(
+          channel,
+          (Object? message) {
+            expect(message, isA<List>());
+            List responses = message as List;
+
+            expect(responses.length, greaterThan(0));
+            expect(responses[0], isA<NativeGraphQLSubscriptionResponse>());
+            NativeGraphQLSubscriptionResponse response = responses[0];
+
+            expect(response.payloadJson, errorsJson);
+            expect(response.subscriptionId.length, greaterThan(0));
+            expect(response.type, 'error');
+
+            return Future.value(message);
+          },
+        );
+
+        expect(responseController, isNotNull);
+        expect(
+          () => responseController?.add(
+            GraphQLResponse<String>(
+              data: payloadJson,
+              errors: [
+                GraphQLResponseError(message: errorMessage1),
+                GraphQLResponseError(message: errorMessage2),
+              ],
+            ),
+          ),
+          returnsNormally,
+        );
+      });
+
+      test('Send Error Event', () async {
+        String exceptionMessage = 'Intentional Error';
+        String errorsJson =
+            '{"errors":[{"message":"Exception: $exceptionMessage"}]}';
+
+        StreamController? responseController;
+
+        mockAPIPlugin.subscribeMethod = <String>(
+          GraphQLRequest mockRequest,
+          void Function()? onEstablished,
+        ) {
+          var controller = StreamController<GraphQLResponse<String>>();
+          responseController = controller;
+          return controller.stream;
+        };
+
+        NativeAmplifyApi nativeAmplifyApi = NativeAmplifyApi({});
+
+        await nativeAmplifyApi.subscribe(
+          NativeGraphQLRequest(document: ''),
+        );
+
+        binding.defaultBinaryMessenger.setMockDecodedMessageHandler<Object?>(
+          channel,
+          (Object? message) {
+            expect(message, isA<List>());
+            List responses = message as List;
+
+            expect(responses.length, greaterThan(0));
+            expect(responses[0], isA<NativeGraphQLSubscriptionResponse>());
+            NativeGraphQLSubscriptionResponse response = responses[0];
+
+            expect(response.payloadJson, errorsJson);
+            expect(response.subscriptionId.length, greaterThan(0));
+            expect(response.type, 'error');
+
+            return Future.value(message);
+          },
+        );
+
+        expect(responseController, isNotNull);
+        expect(
+          () => responseController?.addError(Exception(exceptionMessage)),
+          returnsNormally,
+        );
+      });
+
+      test('Send Done Event', () async {
+        StreamController? responseController;
+
+        mockAPIPlugin.subscribeMethod = <String>(
+          GraphQLRequest mockRequest,
+          void Function()? onEstablished,
+        ) {
+          var controller = StreamController<GraphQLResponse<String>>();
+          responseController = controller;
+          return controller.stream;
+        };
+
+        NativeAmplifyApi nativeAmplifyApi = NativeAmplifyApi({});
+
+        await nativeAmplifyApi.subscribe(
+          NativeGraphQLRequest(document: ''),
+        );
+
+        binding.defaultBinaryMessenger.setMockDecodedMessageHandler<Object?>(
+          channel,
+          (Object? message) {
+            expect(message, isA<List>());
+            List responses = message as List;
+
+            expect(responses.length, greaterThan(0));
+            expect(responses[0], isA<NativeGraphQLSubscriptionResponse>());
+            NativeGraphQLSubscriptionResponse response = responses[0];
+
+            expect(response.payloadJson, null);
+            expect(response.subscriptionId.length, greaterThan(0));
+            expect(response.type, 'complete');
+
+            return Future.value(message);
+          },
+        );
+
+        expect(responseController, isNotNull);
+        expect(
+          () => responseController?.close(),
+          returnsNormally,
+        );
+      });
+
+      group('Unubscribe', () {
+        test('Existing Subscription', () async {
+          mockAPIPlugin.subscribeMethod = <String>(
+            GraphQLRequest mockRequest,
+            void Function()? onEstablished,
+          ) {
+            var controller = StreamController<GraphQLResponse<String>>();
+            return controller.stream;
+          };
+
+          NativeAmplifyApi nativeAmplifyApi = NativeAmplifyApi({});
+
+          var response = await nativeAmplifyApi.subscribe(
+            NativeGraphQLRequest(
+              document: '',
+            ),
+          );
+
+          await nativeAmplifyApi.unsubscribe(response.subscriptionId);
+        });
+
+        test('Fake Subscription', () async {
+          NativeAmplifyApi nativeAmplifyApi = NativeAmplifyApi({});
+
+          await nativeAmplifyApi.unsubscribe('Fake Subscription ID');
+        });
+      });
+    });
+  });
+}
+
+class MockAPIPlugin<T> extends APIPluginInterface {
+  GraphQLOperation<T> Function<T>(GraphQLRequest<T>)? queryMethod;
+  GraphQLOperation<T> Function<T>(GraphQLRequest<T>)? mutateMethod;
+  Stream<GraphQLResponse<T>> Function<T>(GraphQLRequest<T>, void Function()?)?
+      subscribeMethod;
+
+  MockAPIPlugin({
+    this.queryMethod,
+    this.mutateMethod,
+    this.subscribeMethod,
+  });
+
+  void clear() {
+    queryMethod = null;
+    mutateMethod = null;
+    subscribeMethod = null;
+  }
+
+  @override
+  GraphQLOperation<T> query<T>({required GraphQLRequest<T> request}) {
+    return queryMethod!(request);
+  }
+
+  @override
+  GraphQLOperation<T> mutate<T>({required GraphQLRequest<T> request}) {
+    return mutateMethod!(request);
+  }
+
+  @override
+  Stream<GraphQLResponse<T>> subscribe<T>(
+    GraphQLRequest<T> request, {
+    void Function()? onEstablished,
+  }) {
+    return subscribeMethod!(request, onEstablished);
+  }
+}
+
+class MockNativeAuthBridgeCodec extends StandardMessageCodec {
+  @override
+  void writeValue(WriteBuffer buffer, Object? value) {
+    if (value is NativeGraphQLSubscriptionResponse) {
+      buffer.putUint8(128);
+      writeValue(buffer, value.encode());
+    } else {
+      super.writeValue(buffer, value);
+    }
+  }
+
+  @override
+  Object? readValueOfType(int type, ReadBuffer buffer) {
+    switch (type) {
+      case 128:
+        return NativeGraphQLSubscriptionResponse.decode(readValue(buffer)!);
+      default:
+        return super.readValueOfType(type, buffer);
+    }
+  }
+}