polyfill-service/polyfills/String/prototype/repeat/tests.js

A polyfill combinator

/* eslint-env mocha, browser */
/* global proclaim */

it('has correct instance', function () {
	proclaim.isInstanceOf(String.prototype.repeat, Function);
});

it('has correct argument length', function () {
	proclaim.equal(String.prototype.repeat.length, 1);
});

// excellent tests provided by https://github.com/mathiasbynens/String.prototype.repeat

it('works with strings', function () {
	proclaim.equal('abc'.repeat(), '');
	proclaim.equal('abc'.repeat(undefined), '');
	proclaim.equal('abc'.repeat(null), '');
	proclaim.equal('abc'.repeat(false), '');
	proclaim.equal('abc'.repeat(NaN), '');
	proclaim.equal('abc'.repeat('abc'), '');
	proclaim.equal('abc'.repeat(-0), '');
	proclaim.equal('abc'.repeat(+0), '');
	proclaim.equal('abc'.repeat(1), 'abc');
	proclaim.equal('abc'.repeat(2), 'abcabc');
	proclaim.equal('abc'.repeat(3), 'abcabcabc');
	proclaim.equal('abc'.repeat(4), 'abcabcabcabc');
});

it('throws invalid counts', function () {
	proclaim.throws(function () {
		'abc'.repeat(-Infinity);
	});

	proclaim.throws(function () {
		'abc'.repeat(-1);
	});

	proclaim.throws(function() {
		'abc'.repeat(+Infinity);
	});
});

it('works with coercible objects', function () {
	proclaim.equal(String.prototype.repeat.call(42, 4), '42424242');

	proclaim.equal(String.prototype.repeat.call({
		toString: function () {
			return 'abc';
		}
	}, 2), 'abcabc');

	proclaim.equal(String.prototype.repeat.apply(42, [4]), '42424242');

	proclaim.equal(String.prototype.repeat.apply({
		toString: function () {
			return 'abc';
		}
	}, [2]), 'abcabc');
});

var
supportsStrictModeTests = (function () {
	'use strict';

	return this === undefined;
}).call(undefined);

if (supportsStrictModeTests) {
	it('throws incoercible objects', function () {
		proclaim.throws(function () {
			String.prototype.repeat.call(undefined);
		});

		proclaim.throws(function () {
			String.prototype.repeat.call(undefined, 4);
		});

		proclaim.throws(function () {
			String.prototype.repeat.call(null);
		});

		proclaim.throws(function () {
			String.prototype.repeat.call(null, 4);
		});

		proclaim.throws(function () {
			String.prototype.repeat.apply(undefined);
		});

		proclaim.throws(function () {
			String.prototype.repeat.apply(undefined, [4]);
		});

		proclaim.throws(function () {
			String.prototype.repeat.apply(null);
		});

		proclaim.throws(function () {
			String.prototype.repeat.apply(null, [4]);
		});
	});
}