Override alert() during test runs to avoid popups.

        var options = record.get('options');

        options.preview = false; // always disable the preview option

        // Override alert() with empty function, so we don't get

        // disturbing popups during test runs.

        var safeAlert = "var alert = function(){};\n";

        var example = testRunner.add(

            Ext.create('Docs.view.examples.Inline', {

                cls: 'doc-test-preview',

                height: 0,

                value: record.get('code'),

                value: safeAlert + record.get('code'),

                options: options

            })

        );