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();
});