Add role() method to state object

Change-Id: Ie98f15c83d94c6cb1915942bba6c2ba17ae321e0
diff --git a/dev/js/spec/stateSpec.js b/dev/js/spec/stateSpec.js
index 4f71859..fec337c 100644
--- a/dev/js/spec/stateSpec.js
+++ b/dev/js/spec/stateSpec.js
@@ -103,5 +103,24 @@
       expect(obj1.x).toBeFalsy();
       expect(obj2.x).toBeFalsy();
     });
+
+    it('should roll', function () {
+      let s = stateClass.create(['der','alte','mann']);
+
+      expect(s.get()).toEqual('der');
+      s.roll();
+      expect(s.get()).toEqual('alte');
+      s.roll();
+      expect(s.get()).toEqual('mann');
+      s.roll();
+      expect(s.get()).toEqual('der');
+      s.roll();
+      expect(s.get()).toEqual('alte');
+
+      s.set('alte');
+      expect(s.get()).toEqual('alte');
+      s.roll();
+      expect(s.get()).toEqual('mann');
+    });
   });
 });