Files
lodash/test/takeRight.js
Benjamin Tan d5ef31929a Add initial test files from lodash v4. (#4172)
* Install test dependencies.

* Add initial test files.

These files were created using a simplistic AST manipulator using `recast` to
preserve formatting. There's bound to be a huge chunk of errors, but this serves
as a good start. QUnit was replaced with Mocha, with ES2015 imports running via
`esm`.

As far as possible, QUnit-specific syntax has been replaced with Mocha's
`describe` and `it`, while the native Node.js `assert` module is used for
assertions. Files in the `test` directory ending in `.test.js` will be treated
as test files.

* Add initial passing files to test run.
2019-02-12 09:11:32 -08:00

66 lines
2.2 KiB
JavaScript

import assert from 'assert';
import lodashStable from 'lodash';
import { falsey, LARGE_ARRAY_SIZE, isEven } from './utils.js';
import takeRight from '../takeRight.js';
describe('takeRight', function() {
var array = [1, 2, 3];
it('should take the last two elements', function() {
assert.deepStrictEqual(takeRight(array, 2), [2, 3]);
});
it('should treat falsey `n` values, except `undefined`, as `0`', function() {
var expected = lodashStable.map(falsey, function(value) {
return value === undefined ? [3] : [];
});
var actual = lodashStable.map(falsey, function(n) {
return takeRight(array, n);
});
assert.deepStrictEqual(actual, expected);
});
it('should return an empty array when `n` < `1`', function() {
lodashStable.each([0, -1, -Infinity], function(n) {
assert.deepStrictEqual(takeRight(array, n), []);
});
});
it('should return all elements when `n` >= `length`', function() {
lodashStable.each([3, 4, Math.pow(2, 32), Infinity], function(n) {
assert.deepStrictEqual(takeRight(array, n), array);
});
});
it('should work as an iteratee for methods like `_.map`', function() {
var array = [[1, 2, 3], [4, 5, 6], [7, 8, 9]],
actual = lodashStable.map(array, takeRight);
assert.deepStrictEqual(actual, [[3], [6], [9]]);
});
it('should work in a lazy sequence', function() {
var array = lodashStable.range(LARGE_ARRAY_SIZE),
predicate = function(value) { values.push(value); return isEven(value); },
values = [],
actual = _(array).takeRight(2).takeRight().value();
assert.deepEqual(actual, takeRight(takeRight(array)));
actual = _(array).filter(predicate).takeRight(2).takeRight().value();
assert.deepEqual(values, array);
assert.deepEqual(actual, takeRight(takeRight(_.filter(array, predicate), 2)));
actual = _(array).takeRight(6).take(4).takeRight(2).take().value();
assert.deepEqual(actual, _.take(takeRight(_.take(takeRight(array, 6), 4), 2)));
values = [];
actual = _(array).filter(predicate).takeRight(6).take(4).takeRight(2).take().value();
assert.deepEqual(values, array);
assert.deepEqual(actual, _.take(takeRight(_.take(takeRight(_.filter(array, predicate), 6), 4), 2)));
});
});