From fa27c3479ffc4edcadd5ec4889ec10dee723f26f Mon Sep 17 00:00:00 2001
From: Dmytro Nikulin <dmytronikulin@Dmytros-MacBook-Air.local>
Date: Fri, 27 Feb 2026 11:24:13 +0200
Subject: [PATCH 1/3] Add solution

---
 src/isIsogram.test.js | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/src/isIsogram.test.js b/src/isIsogram.test.js
index dfb16184..d4b2535f 100644
--- a/src/isIsogram.test.js
+++ b/src/isIsogram.test.js
@@ -6,4 +6,24 @@ describe('isIsogram', () => {
   it(`should be declared`, () => {
     expect(isIsogram).toBeInstanceOf(Function);
   });
+
+  it(`should return true for empty string`, () => {
+    expect(isIsogram('')).toBe(true);
+  });
+
+  it(`should return true
+    if all the letters in the string are different`, () => {
+    expect(isIsogram('polygraphic')).toBe(true);
+  });
+
+  it(`should return false
+    if any of the letters in the string repeat`, () => {
+    expect(isIsogram('whoops')).toBe(false);
+  });
+
+  it(`should return false
+    if any of the letters in the string repeat
+    while ignoring the letter case`, () => {
+    expect(isIsogram('Analogy')).toBe(false);
+  });
 });

From ea9a06fbc491babe215fad00b34e3a92e917c587 Mon Sep 17 00:00:00 2001
From: Dmytro Nikulin <dmytronikulin@Dmytros-MacBook-Air.local>
Date: Fri, 27 Feb 2026 11:24:47 +0200
Subject: [PATCH 2/3] Add solution

---
 src/isIsogram.test.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/isIsogram.test.js b/src/isIsogram.test.js
index d4b2535f..20ca2724 100644
--- a/src/isIsogram.test.js
+++ b/src/isIsogram.test.js
@@ -13,7 +13,7 @@ describe('isIsogram', () => {
 
   it(`should return true
     if all the letters in the string are different`, () => {
-    expect(isIsogram('polygraphic')).toBe(true);
+    expect(isIsogram('playground')).toBe(true);
   });
 
   it(`should return false

From 4315a6fdda0466bc847573506be38d67b6f06322 Mon Sep 17 00:00:00 2001
From: Dmytro Nikulin <dmytronikulin@Dmytros-MacBook-Air.local>
Date: Fri, 27 Feb 2026 11:28:12 +0200
Subject: [PATCH 3/3] Changed test conditions

---
 src/isIsogram.test.js | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/src/isIsogram.test.js b/src/isIsogram.test.js
index 20ca2724..5b4a7672 100644
--- a/src/isIsogram.test.js
+++ b/src/isIsogram.test.js
@@ -13,17 +13,23 @@ describe('isIsogram', () => {
 
   it(`should return true
     if all the letters in the string are different`, () => {
-    expect(isIsogram('playground')).toBe(true);
+    expect(isIsogram('playgrounds')).toBe(true);
   });
 
   it(`should return false
     if any of the letters in the string repeat`, () => {
-    expect(isIsogram('whoops')).toBe(false);
+    expect(isIsogram('look')).toBe(false);
   });
 
   it(`should return false
     if any of the letters in the string repeat
     while ignoring the letter case`, () => {
-    expect(isIsogram('Analogy')).toBe(false);
+    expect(isIsogram('Adam')).toBe(false);
+  });
+
+  it(`should return false
+    if any of the letters in the string repeat
+    while ignoring the letter case and their positions`, () => {
+    expect(isIsogram('Oops')).toBe(false);
   });
 });