Updated the test system

test/none.test.js

@@ -0,0 +1,18 @@
+const expect = require('expect');
+const {none} = require('./_30s.js');
+
+test('none is a Function', () => {
+  expect(none).toBeInstanceOf(Function);
+});
+test('Returns true for arrays with no truthy values', () => {
+  expect(none([0, undefined, NaN, null, ''])).toBeTruthy();
+});
+test('Returns false for arrays with at least one truthy value', () => {
+  expect(none([0, 1])).toBeFalsy();
+});
+test('Returns true with a predicate function', () => {
+  expect(none([4, 1, 0, 3], x => x < 0)).toBeTruthy();
+});
+test('Returns false with predicate function', () => {
+  expect(none([0, 1, 2], x => x === 1)).toBeFalsy();
+});