👌 IMPROVE: Added test cases for Project Euler Problem 4

Author: omkarnathparida

Project-Euler/test/Problem004.test.js

@@ -0,0 +1,11 @@
+import { largestPalindromic } from '../Problem004.js'
+
+describe('Largest Palindromic Number', () => {
+  test('if digit is 2', () => {
+    expect(largestPalindromic(2)).toBe(9009)
+  })
+  // Project Euler Condition Check
+  test('if digit is 3', () => {
+    expect(largestPalindromic(3)).toBe(906609)
+  })
+})