konva/tests/js/unit/layerTests.js

Test.Modules.LAYER = {
    'beforeDraw and afterDraw': function(containerId) {
        var stage = new Kinetic.Stage({
            container: containerId,
            width: 578,
            height: 200
        });

        var layer = new Kinetic.Layer();

        var circle = new Kinetic.Circle({
            x: 100,
            y: stage.getHeight() / 2,
            radius: 70,
            fill: 'green',
            stroke: 'black',
            strokeWidth: 4
        });

        layer.add(circle);
        stage.add(layer);

        var counter = 0;

        layer.beforeDraw(function() {
            counter++;
            test(counter === 1, 'counter should be 1');
        });

        layer.afterDraw(function() {
            counter++;
            test(counter === 2, 'counter should be 2');
        });

        layer.draw();
    },
    'set clearBeforeDraw to false, and test toDataURL for stage, layer, group, and shape': function(containerId) {
        var stage = new Kinetic.Stage({
            container: containerId,
            width: 578,
            height: 200
        });

        var layer = new Kinetic.Layer({
            clearBeforeDraw: false,
            throttle: 999
        });

        var group = new Kinetic.Group();

        var circle = new Kinetic.Circle({
            x: 100,
            y: stage.getHeight() / 2,
            radius: 70,
            fill: 'green',
            stroke: 'black',
            strokeWidth: 4
        });

        group.add(circle);
        layer.add(group);
        stage.add(layer);

        for(var n = 0; n < 20; n++) {
            circle.move(10, 0);
            layer.draw();
        }

        //console.log(layer.toDataURL());

        stage.toDataURL({
            callback: function(dataUrl) {
                warn(dataUrls['stacked green circles'] === dataUrl, 'stacked green circles stage data url is incorrect');
            }
        });
        warn(dataUrls['stacked green circles'] === layer.toDataURL(), 'stacked green circles layer data url is incorrect');

    }
};