merge: Add test case to Vigenere Cipher Algorithm (TheAlgorithms#1017)

Author: Ankush263

Ciphers/test/VigenereCipher.test.js

@@ -0,0 +1,13 @@
+import { encrypt, decrypt } from '../VigenereCipher'
+
+test('Hello world! === dcrypt(encrypt(Hello world!))', () => {
+  const word = 'Hello world!'
+  const result = decrypt(encrypt(word, 'code'), 'code')
+  expect(result).toMatch(word)
+})
+
+test('The Algorithms === dcrypt(encrypt(The Algorithms))', () => {
+  const word = 'The Algorithms'
+  const result = decrypt(encrypt(word, 'code'), 'code')
+  expect(result).toMatch(word)
+})