Untitled

var fs = require('fs');
var webserver = require('webserver');

casper.test.begin('Image onload should be invoked', 1, {
    setUp: function() {
        var server = webserver.create();
        this.server = server.listen(8080, function(request, response) {
            if (request.url == '/') {
                response.writeHead(200, { 'Content-Type': 'text/html' });

                response.write('' +
                    '<!doctype html>n' +
                    '<html>n' +
                        '<head>n' +
                            '<script type="text/javascript">n' +
                                'window.onload = function() {n' +
                                    'var px = document.createElement("img");n' +
                                    'px.onload = function() {n' +
                                        'window._pxLoad = true;n' +
                                    '};n' +
                                    'px.src = "px.gif";n' +
                                '};n' +
                            '</script>n' +
                        '</head>n' +
                        '<body></body>n' +
                    '</html>' +
                '');
            } else if (request.url.match(/px.gif$/i)) {
                response.writeHead(200, {
                    'Content-Type': 'image/gif',
                    'Cache-Control': 'no-cache'
                });

                var filePath = fs.workingDirectory + request.url.split('/').join(fs.separator).replace(/d/gi, '');

                response.write(fs.read(filePath));
            }

            response.close();
        });
    },

    tearDown: function() {
        this.server.close();
    },

    test: function(test) {
        casper.start('http://localhost:8190', function() {
            this.waitFor(function() {
                return this.evaluate(function () {
                    return window._pxLoad !== undefined;
                });
            }, function then() {
                var flag = this.evaluate(function () {
                    return window._pxLoad;
                });

                test.assertTruthy(flag, 'Image has been successfully loaded');
            });
        });

        casper.run(function () {
            test.done();
        });
    }
});