TF-1233 Fix error out of range in create avatar icon

core/lib/presentation/extensions/string_extension.dart

@@ -1,7 +1,9 @@
+import 'package:core/utils/app_logger.dart';
 
 extension StringExtension on String {
 
   String get firstLetterToUpperCase {
+    try {
       final listWord = split(' ');
       if (listWord.length > 1) {
         final regexLetter = RegExp("([A-Za-z])");
@@ -27,9 +29,13 @@ extension StringExtension on String {
               ? '${firstLetter.toUpperCase()}${secondLetter.toUpperCase()}'
               : '';
         } else {
-        final firstLetter = listMatch[0].group(0);
+          final firstLetter = substring(0, length > 1 ? 2 : 1);
-        return firstLetter != null ? firstLetter.toUpperCase() : '';
+          return firstLetter.toUpperCase();
         }
       }
+    } catch (e) {
+      logError('StringExtension::firstLetterToUpperCase(): $e');
+      return '';
+    }
   }
 }

core/test/presentation/extensions/string_extension_test.dart

@@ -0,0 +1,61 @@
+import 'package:core/presentation/extensions/string_extension.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  group("firstLetterToUpperCase()", () {
+    test("from 2 digits number", () {
+      const twentyThree = '23';
+      expect(twentyThree.firstLetterToUpperCase, equals('23'));
+    });
+
+    test("from 3 digits number", () {
+      const twentyThreeThree = '233';
+      expect(twentyThreeThree.firstLetterToUpperCase, equals('23'));
+    });
+
+    test("from 1 digit number", () {
+      const two = '2';
+      expect(two.firstLetterToUpperCase, equals('2'));
+    });
+
+    test("from 1 character", () {
+      const two = 'A';
+      expect(two.firstLetterToUpperCase, equals('A'));
+    });
+
+    test("from name with multiple words", () {
+      const name = 'Grant big';
+      expect(name.firstLetterToUpperCase, equals('GB'));
+    });
+
+    test("from name with one word", () {
+      const name = 'Grant';
+      expect(name.firstLetterToUpperCase, equals('GR'));
+    });
+
+    test("from name mix with number and word", () {
+      const name = '23 Grant';
+      expect(name.firstLetterToUpperCase, equals('GG'));
+    });
+
+    test("from name mix with word and number", () {
+      const name = 'Grant 23';
+      expect(name.firstLetterToUpperCase, equals('GG'));
+    });
+
+    test("from empty string", () {
+      const name = '';
+      expect(name.firstLetterToUpperCase, equals(''));
+    });
+
+    test("from special string", () {
+      const name = '&^%';
+      expect(name.firstLetterToUpperCase, equals('&^'));
+    });
+
+    test("from multiple special string", () {
+      const name = '&^% *()^';
+      expect(name.firstLetterToUpperCase, equals(''));
+    });
+  });
+}