Updated the test system

test/isArrayLike.test.js

@@ -0,0 +1,15 @@
+const expect = require('expect');
+const {isArrayLike} = require('./_30s.js');
+
+test('isArrayLike is a Function', () => {
+  expect(isArrayLike).toBeInstanceOf(Function);
+});
+test('Returns true for a string', () => {
+  expect(isArrayLike('abc')).toBeTruthy();
+});
+test('Returns true for an array', () => {
+  expect(isArrayLike([1, 2, 3])).toBeTruthy();
+});
+test('Returns false for null', () => {
+  expect(isArrayLike(null)).toBeFalsy();
+});