From bb3ae137afa8b9df9a076ca6c3f8f82dbe5e9f36 Mon Sep 17 00:00:00 2001
From: Aakash Sadhu <aakashsadhu@hotmail.com>
Date: Fri, 1 May 2026 06:20:17 +0100
Subject: [PATCH] solution

---
 src/isIsogram.test.js | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/src/isIsogram.test.js b/src/isIsogram.test.js
index dfb16184..2e58e1e7 100644
--- a/src/isIsogram.test.js
+++ b/src/isIsogram.test.js
@@ -6,4 +6,20 @@ describe('isIsogram', () => {
   it(`should be declared`, () => {
     expect(isIsogram).toBeInstanceOf(Function);
   });
+
+  it('should return true for a word without repeating letters', () => {
+    expect(isIsogram('playgrounds')).toBe(true);
+  });
+
+  it('should return true for an empty string', () => {
+    expect(isIsogram('')).toBe(true);
+  });
+
+  it('should return false for a word with repeating letters', () => {
+    expect(isIsogram('look')).toBe(false);
+  });
+
+  it('should return false for repeating letters in different cases', () => {
+    expect(isIsogram('Adam')).toBe(false);
+  });
 });