unique-selector.js

var unique = require('unique-selector');

function assert(expr, msg) {
    if (!expr) throw new Error(msg || 'failed');
}

describe('unique-selector', function() {
    describe('with undefined', function() {
        it('should return a TypeError', function() {
            try {
                unique();
                assert(false);
            } catch(e) {
                assert(e instanceof TypeError);
            }
        });
    });

    describe('with Object', function() {
        it('should return a TypeError', function() {
            try {
                unique({});
                assert(false);
            } catch(e) {
                assert(e instanceof TypeError);
            }
        });
    });

    var selectors = {
        // Selector: expected
        'HTML > BODY':
            'html > body',
        'HTML > BODY > DIV#fixture':
            '#fixture',
        'HTML > BODY > DIV#fixture > H3 > SMALL':
            '#fixture > h3 > small',
        'HTML > BODY > DIV#fixture > UL#nav > LI:nth-child(1)':
            '#nav > li.first.item',
        'HTML > BODY > DIV#fixture > UL#nav > LI:nth-child(2)':
            '#nav > li.collapsed.item:nth-child(2)',
        'HTML > BODY > DIV#fixture > UL#nav > LI:nth-child(3)':
            '#nav > li.last.collapsed.item',
        'HTML > BODY > DIV#fixture > UL#nav > LI.item > UL#nested > LI.child > IMG':
            '#nested > li.child > img[alt="Some Title"]'
    };

    for (selector in selectors) {
        describe('with ' + selector, function() {
            var expected    = selectors[selector];
            var actual      = unique(document.querySelector(selector));

            it('should return `' + expected + '`', function() {
                assert(expected === actual, actual);
            });

            it('should have only 1 match', function() {
                assert(1 === document.querySelectorAll(selector).length);
            });
        });
    }
});