Updated the test system

test/isDivisible.test.js

@@ -0,0 +1,9 @@
+const expect = require('expect');
+const {isDivisible} = require('./_30s.js');
+
+test('isDivisible is a Function', () => {
+  expect(isDivisible).toBeInstanceOf(Function);
+});
+test('The number 6 is divisible by 3', () => {
+  expect(isDivisible(6, 3)).toBeTruthy();
+});