TF-3278 Handle open app via deep link at MailboxDashboard screen

core/test/utils/string_convert_test.dart

@@ -5,6 +5,42 @@ import 'package:core/utils/string_convert.dart';
 import 'package:flutter_test/flutter_test.dart';
 
 void main() {
+  group('StringConvert::decodeBase64ToString::test', () {
+    test('should decode a valid Base64 string to a normal string', () {
+      // Arrange
+      const base64Encoded = 'SGVsbG8gV29ybGQh';
+      const expectedDecoded = 'Hello World!';
+
+      // Act
+      final result = StringConvert.decodeBase64ToString(base64Encoded);
+
+      // Assert
+      expect(result, expectedDecoded);
+    });
+
+    test('should return the original string for invalid Base64 input', () {
+      // Arrange
+      const invalidBase64 = 'InvalidBase64@@';
+
+      // Act
+      final result = StringConvert.decodeBase64ToString(invalidBase64);
+
+      // Assert
+      expect(result, invalidBase64);
+    });
+
+    test('should return the original string for empty input', () {
+      // Arrange
+      const emptyInput = '';
+
+      // Act
+      final result = StringConvert.decodeBase64ToString(emptyInput);
+
+      // Assert
+      expect(result, emptyInput);
+    });
+  });
+
   group('StringConvert::extractStrings::', () {
     group('Basic Functionality', () {
       test('should extract strings separated by spaces', () {