merge: Add test Case for Palindrome Recursive (#855)

* Add test Case for Palindrome Recursive

* Update Checks

Recursive/test/palindrome.test.js

@@ -0,0 +1,24 @@
+import { palindrome } from '../Palindrome'
+
+describe('Palindrome', () => {
+  it('expects to return true for palindrome string', () => {
+    const isPalindrome = palindrome('madam')
+    expect(isPalindrome).toBe(true)
+  })
+
+  it('expects to return true for Empty String', () => {
+    const isPalindrome = palindrome('')
+    expect(isPalindrome).toBe(true)
+  })
+
+  it('expects to return false for non-palindrome string', () => {
+    const isPalindrome = palindrome('foobar')
+    expect(isPalindrome).toBe(false)
+  })
+
+  it('Throw Error for Invalid Input', () => {
+    expect(() => palindrome(123)).toThrow('Invalid Input')
+    expect(() => palindrome(null)).toThrow('Invalid Input')
+    expect(() => palindrome(undefined)).toThrow('Invalid Input')
+  })
+})