Updated the test system

test/fibonacci.test.js

@@ -0,0 +1,9 @@
+const expect = require('expect');
+const {fibonacci} = require('./_30s.js');
+
+test('fibonacci is a Function', () => {
+  expect(fibonacci).toBeInstanceOf(Function);
+});
+test('Generates an array, containing the Fibonacci sequence', () => {
+  expect(fibonacci(6)).toEqual([0, 1, 1, 2, 3, 5]);
+});