use imageData in the crop test

test/unit/image-editor.js

@@ -13,13 +13,12 @@ QUnit.test('should crop image', function( assert ) {
   var done = assert.async();
   var editor = new ImageEditor('canvas');
   editor.loadImage('fixtures/dog.jpg', function() {
-    editor.crop(400, 100, 'cm');
-    var data = editor.canvas.getViewport().getData();
-    assert.equal(data.dim.width, 400, 'sets crop width');
-    assert.equal(data.dim.height, 100, 'sets crop height');
-    assert.equal(data.dim.units, 'cm', 'set units');
-    assert.equal(data.width, 1049, 'sets image width');
-    assert.equal(data.height, 262.25, 'sets image height');
+    editor.crop(400, 200, 'cm');
+    var data = editor.canvas.getImageData().getData();
+    assert.strictEqual(data.width, 400, 'sets image width');
+    assert.strictEqual(data.height, 200, 'sets image height');
+    assert.strictEqual(data.x, 0, 'sets crop x');
+    assert.equal(data.y, 0.12482117310443483, 'sets crop y');
     done();
   });
 });