diff --git a/spec/gridstack-engine-spec.js b/spec/gridstack-engine-spec.js
new file mode 100644
index 0000000..d836676
--- /dev/null
+++ b/spec/gridstack-engine-spec.js
@@ -0,0 +1,41 @@
+describe('gridstack engine', function() {
+    'use strict';
+
+    var e;
+    var w;
+    var engine;
+
+    beforeEach(function() {
+        w = window;
+        e = w.GridStackUI.Engine;
+        engine = new w.GridStackUI.Engine(12);
+    });
+
+    describe('test constructor', function() {
+        it('should be setup properly', function() {
+            expect(engine.width).toEqual(12);
+            expect(engine.float).toEqual(false);
+            expect(engine.height).toEqual(0);
+            expect(engine.nodes).toEqual([]);
+        });
+    });
+
+    describe('test _prepareNode', function() {
+        it('should prepare a node', function() {
+            expect(engine._prepareNode({}, false)).toEqual(jasmine.objectContaining({x: 0, y: 0, width: 1, height: 1}));
+            expect(engine._prepareNode({x: 10}, false)).toEqual(jasmine.objectContaining({x: 10, y: 0, width: 1, height: 1}));
+            expect(engine._prepareNode({x: -10}, false)).toEqual(jasmine.objectContaining({x: 0, y: 0, width: 1, height: 1}));
+            expect(engine._prepareNode({y: 10}, false)).toEqual(jasmine.objectContaining({x: 0, y: 10, width: 1, height: 1}));
+            expect(engine._prepareNode({y: -10}, false)).toEqual(jasmine.objectContaining({x: 0, y: 0, width: 1, height: 1}));
+            expect(engine._prepareNode({width: 3}, false)).toEqual(jasmine.objectContaining({x: 0, y: 0, width: 3, height: 1}));
+            expect(engine._prepareNode({width: 100}, false)).toEqual(jasmine.objectContaining({x: 0, y: 0, width: 12, height: 1}));
+            expect(engine._prepareNode({width: 0}, false)).toEqual(jasmine.objectContaining({x: 0, y: 0, width: 1, height: 1}));
+            expect(engine._prepareNode({width: -190}, false)).toEqual(jasmine.objectContaining({x: 0, y: 0, width: 1, height: 1}));
+            expect(engine._prepareNode({height: 3}, false)).toEqual(jasmine.objectContaining({x: 0, y: 0, width: 1, height: 3}));
+            expect(engine._prepareNode({height: 0}, false)).toEqual(jasmine.objectContaining({x: 0, y: 0, width: 1, height: 1}));
+            expect(engine._prepareNode({height: -10}, false)).toEqual(jasmine.objectContaining({x: 0, y: 0, width: 1, height: 1}));
+            expect(engine._prepareNode({x: 4, width: 10}, false)).toEqual(jasmine.objectContaining({x: 2, y: 0, width: 10, height: 1}));
+            expect(engine._prepareNode({x: 4, width: 10}, true)).toEqual(jasmine.objectContaining({x: 4, y: 0, width: 8, height: 1}));
+        });
+    });
+});