toUppercase tool, testCases and updated index file

src/pages/string/uppercase/uppercase.service.test.ts

@@ -0,0 +1,34 @@
+import { expect, describe, it } from 'vitest';
+import { toUppercase } from './service';
+
+describe('toUppercase', () => {
+    test('should convert a lowercase string to uppercase', () => {
+        const input = 'hello';
+        const result = toUppercase(input);
+        expect(result).toBe('HELLO');
+    });
+
+    test('should convert a mixed case string to uppercase', () => {
+        const input = 'HeLLo WoRLd';
+        const result = toUppercase(input);
+        expect(result).toBe('HELLO WORLD');
+    });
+
+    test('should convert an already uppercase string to uppercase', () => {
+        const input = 'HELLO';
+        const result = toUppercase(input);
+        expect(result).toBe('HELLO');
+    });
+
+    test('should handle an empty string', () => {
+        const input = '';
+        const result = toUppercase(input);
+        expect(result).toBe('');
+    });
+
+    test('should handle a string with numbers and symbols', () => {
+        const input = '123 hello! @world';
+        const result = toUppercase(input);
+        expect(result).toBe('123 HELLO! @WORLD');
+    });
+});