Updated the test system

test/castArray.test.js

@@ -0,0 +1,21 @@
+const expect = require('expect');
+const {castArray} = require('./_30s.js');
+
+test('castArray is a Function', () => {
+  expect(castArray).toBeInstanceOf(Function);
+});
+test('Works for single values', () => {
+  expect(castArray(1)).toEqual([1]);
+});
+test('Works for arrays with one value', () => {
+  expect(castArray([1])).toEqual([1]);
+});
+test('Works for arrays with multiple value', () => {
+  expect(castArray([1, 2, 3])).toEqual([1, 2, 3]);
+});
+test('Works for strings', () => {
+  expect(castArray('test')).toEqual(['test']);
+});
+test('Works for objects', () => {
+  expect(castArray({})).toEqual([{}]);
+});