Files
30-seconds-of-code/test/head.test.js
Christian Melgarejo Bresanovich ec28d5fa6f Update snippets head and last to type check
Update `head` and `last` to check on empty, undefined, null arrays.
2019-12-11 03:17:18 -03:00

33 lines
1018 B
JavaScript

const {head} = require('./_30s.js');
test('head is a Function', () => {
expect(head).toBeInstanceOf(Function);
});
test('head({ a: 1234}) returns undefined', () => {
expect(head({ a: 1234 }) === undefined).toBeTruthy();
});
test('head([1, 2, 3]) returns 1', () => {
expect(head([1, 2, 3])).toBe(1);
});
test('head({ 0: false}) returns false', () => {
expect(head({ 0: false })).toBeFalsy();
});
test('head(String) returns S', () => {
expect(head('String')).toBe('S');
});
test('head(null) returns undefined', () => {
expect(head(null)).toBe(undefined);
});
test('head(undefined) returns undefined', () => {
expect(head(undefined)).toBe(undefined);
});
test('head() returns undefined', () => {
expect(head()).toBe(undefined);
});
let start = new Date().getTime();
head([1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 1122, 32124, 23232]);
let end = new Date().getTime();
test('head([1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 1122, 32124, 23232]) takes less than 2s to run', () => {
expect(end - start < 2000).toBeTruthy();
});