Testing Navigation servcie

test/helpers/test_helpers.dart

@@ -126,6 +126,13 @@ NavigationService getAndRegisterNavigationService() {
   when(service.pushScreen(any, arguments: anyNamed('arguments')))
       .thenAnswer((_) async {});
   when(service.popAndPushScreen(any, arguments: '-1')).thenAnswer((_) async {});
+  when(service.pushReplacementScreen(any, arguments: anyNamed('arguments')))
+      .thenAnswer((_) async {});
+  when(service.pushDialog(any)).thenReturn(null);
+  when(service.showSnackBar(any)).thenReturn(null);
+  when(service.showTalawaErrorSnackBar(any, any)).thenReturn(null);
+  when(service.showTalawaErrorDialog(any, any)).thenReturn(null);
+  when(service.pop()).thenReturn(null);
   locator.registerSingleton<NavigationService>(service);
   return service;
 }

test/service_tests/naviagtion_service_test.dart

@@ -0,0 +1,123 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:mockito/mockito.dart';
+import 'package:talawa/enums/enums.dart';
+import '../helpers/test_helpers.dart';
+import '../helpers/test_locator.dart';
+
+/// Test for navigation_service.dart.
+///
+/// more_info_if_required
+///
+/// **params**:
+///   None
+///
+/// **returns**:
+///   None
+void main() {
+  testSetupLocator();
+
+  setUp(() {
+    registerServices();
+  });
+
+  tearDown(() {
+    unregisterServices();
+  });
+
+  group('Testing all functions in NavigationService', () {
+    test('NavigationService should call pushScreen with correct route',
+        () async {
+      await navigationService.pushScreen('testRoute', arguments: 'testArgs');
+      verify(navigationService.pushScreen('testRoute', arguments: 'testArgs'))
+          .called(1);
+    });
+
+    test('NavigationService should call popAndPushScreen with correct route',
+        () async {
+      await navigationService.popAndPushScreen(
+        'newRoute',
+        arguments: 'newArgs',
+      );
+      verify(
+        navigationService.popAndPushScreen(
+          'newRoute',
+          arguments: 'newArgs',
+        ),
+      ).called(1);
+    });
+
+    test(
+        'NavigationService should call pushReplacementScreen with correct route',
+        () async {
+      await navigationService.pushReplacementScreen(
+        'replacementRoute',
+        arguments: 'replacementArgs',
+      );
+      verify(
+        navigationService.pushReplacementScreen(
+          'replacementRoute',
+          arguments: 'replacementArgs',
+        ),
+      ).called(1);
+    });
+
+    test('NavigationService should call removeAllAndPush with correct routes',
+        () async {
+      await navigationService.removeAllAndPush(
+        'routeName',
+        '/tillRoute',
+        arguments: 'args',
+      );
+      verify(
+        navigationService.removeAllAndPush(
+          'routeName',
+          '/tillRoute',
+          arguments: 'args',
+        ),
+      ).called(1);
+    });
+
+    test('NavigationService should call pushDialog with correct widget',
+        () async {
+      const testDialog = Text('Test Dialog');
+      navigationService.pushDialog(testDialog);
+      verify(navigationService.pushDialog(testDialog)).called(1);
+    });
+
+    test('NavigationService should call showSnackBar with correct message', () {
+      const testMessage = 'Test Message';
+      navigationService.showSnackBar(testMessage);
+      verify(navigationService.showSnackBar(testMessage)).called(1);
+    });
+
+    test(
+        'NavigationService should call showTalawaErrorSnackBar with correct message and type',
+        () {
+      const errorMessage = 'Error Message';
+      const messageType = MessageType.error;
+      navigationService.showTalawaErrorSnackBar(errorMessage, messageType);
+      verify(
+        navigationService.showTalawaErrorSnackBar(
+          errorMessage,
+          messageType,
+        ),
+      ).called(1);
+    });
+
+    test(
+        'NavigationService should call showTalawaErrorDialog with correct message and type',
+        () {
+      const errorMessage = 'Error Dialog Message';
+      const messageType = MessageType.error;
+      navigationService.showTalawaErrorDialog(errorMessage, messageType);
+      verify(navigationService.showTalawaErrorDialog(errorMessage, messageType))
+          .called(1);
+    });
+
+    test('NavigationService should call pop', () {
+      navigationService.pop();
+      verify(navigationService.pop()).called(1);
+    });
+  });
+}