Test for join_organisation_after_auth.dart (PalisadoesFoundation#2260)

* Test for join_organisation_after_auth.dart

* modify

* adding more tests for complete coverage

test/views/after_auth_screens/join_organisation_after_auth_test.dart

@@ -4,26 +4,31 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_localizations/flutter_localizations.dart';
 import 'package:flutter_test/flutter_test.dart';
+import 'package:mockito/mockito.dart';
+import 'package:qr_code_scanner/qr_code_scanner.dart';
 import 'package:talawa/enums/enums.dart';
 import 'package:talawa/models/organization/org_info.dart';
 import 'package:talawa/models/user/user_info.dart';
 import 'package:talawa/services/graphql_config.dart';
 import 'package:talawa/services/size_config.dart';
 import 'package:talawa/utils/app_localization.dart';
-import 'package:talawa/view_model/lang_view_model.dart';
 import 'package:talawa/view_model/pre_auth_view_models/select_organization_view_model.dart';
 import 'package:talawa/views/after_auth_screens/join_org_after_auth/join_organisation_after_auth.dart';
 import 'package:talawa/views/base_view.dart';
 import 'package:talawa/widgets/organization_search_list.dart';
 
 import '../../helpers/test_helpers.dart';
+import '../../helpers/test_helpers.mocks.dart';
 import '../../helpers/test_locator.dart';
 
-Widget createJoinOrgAfterAuth({String orgId = "fake_id"}) {
-  return BaseView<AppLanguage>(
-    onModelReady: (model) => model.initialize(),
-    builder: (context, langModel, child) {
+Widget createJoinOrgAfterAuth({
+  String orgId = "fake_id",
+}) {
+  return BaseView<SelectOrganizationViewModel>(
+    onModelReady: (model) => model.initialise(orgId),
+    builder: (context, model, child) {
       return MaterialApp(
+        navigatorKey: navigationService.navigatorKey,
         locale: const Locale('en'),
         localizationsDelegates: const [
           AppLocalizationsDelegate(isTest: true),
@@ -53,6 +58,99 @@ void main() {
   });
 
   group("Tests for JoinOrganizationAfterAuth - widgets", () {
+    testWidgets('QR Scan Test', (WidgetTester tester) async {
+      final controller = MockQRViewController();
+      when(controller.scannedDataStream).thenAnswer((_) async* {
+        yield Barcode(
+          ' ' + '?orgid=6737904485008f171cf29924',
+          BarcodeFormat.qrcode,
+          null,
+        );
+      });
+      when(controller.stopCamera())
+          .thenAnswer((realInvocation) => Future.value());
+
+      await tester.pumpWidget(
+        createJoinOrgAfterAuth(),
+      );
+
+      await tester.pumpAndSettle(const Duration(seconds: 6));
+
+      await tester.tap(find.byIcon(Icons.qr_code_scanner));
+      await tester.pumpAndSettle();
+
+      expect(
+        find.byWidgetPredicate(
+          (widget) =>
+              widget is ClipRRect &&
+              widget.child is Container &&
+              (widget.child! as Container).child is Column,
+        ),
+        findsOneWidget,
+      );
+      (tester.widget(find.byType(QRView)) as QRView)
+          .onQRViewCreated(controller);
+    });
+    testWidgets('QR Scan Test when url != GraphqlConfig.orgURI',
+        (WidgetTester tester) async {
+      final controller = MockQRViewController();
+      when(controller.scannedDataStream).thenAnswer((_) async* {
+        yield Barcode(
+          '1' + '?orgid=6737904485008f171cf29924',
+          BarcodeFormat.qrcode,
+          null,
+        );
+      });
+      when(controller.stopCamera())
+          .thenAnswer((realInvocation) => Future.value());
+
+      await tester.pumpWidget(
+        createJoinOrgAfterAuth(),
+      );
+
+      await tester.pumpAndSettle(const Duration(seconds: 6));
+
+      await tester.tap(find.byIcon(Icons.qr_code_scanner));
+      await tester.pumpAndSettle();
+
+      expect(
+        find.byWidgetPredicate(
+          (widget) =>
+              widget is ClipRRect &&
+              widget.child is Container &&
+              (widget.child! as Container).child is Column,
+        ),
+        findsOneWidget,
+      );
+      (tester.widget(find.byType(QRView)) as QRView)
+          .onQRViewCreated(controller);
+    });
+    testWidgets('Test _onQRViewCreated when throwing exception',
+        (WidgetTester tester) async {
+      final controller = MockQRViewController();
+      when(controller.scannedDataStream).thenAnswer((_) async* {
+        yield Barcode(
+          ' ' + '?orgid=6737904485008f171cf29924',
+          BarcodeFormat.qrcode,
+          null,
+        );
+      });
+      when(controller.stopCamera())
+          .thenAnswer((realInvocation) => Future.value());
+
+      await tester.pumpWidget(
+        createJoinOrgAfterAuth(),
+      );
+      when(controller.stopCamera()).thenThrow(Exception("exception"));
+
+      await tester.pumpAndSettle(const Duration(seconds: 6));
+
+      await tester.tap(find.byIcon(Icons.qr_code_scanner));
+      await tester.pumpAndSettle();
+
+      (tester.widget(find.byType(QRView)) as QRView)
+          .onQRViewCreated(controller);
+    });
     testWidgets(
       "Check if JoinOrganizationsAfterAuth shows up",
       (tester) async {
@@ -132,13 +230,6 @@ void main() {
     /// Search is No-Longer is a feature, if it gets implemented in future use this test
     /// Really good test to learn from so not deleting
     testWidgets("Check if model related functions work", (tester) async {
-      // Registers a singleton, which means that every instance of
-      // SelectOrganizationViewModel will be the same.
-      locator.unregister<SelectOrganizationViewModel>();
-      locator.registerSingleton<SelectOrganizationViewModel>(
-        SelectOrganizationViewModel(),
-      );
-
       final orgOne = OrgInfo(
         name: "org_one",
         creatorInfo: User(