Add two trivial tests for the presence and default

value of OpenLayers.ImgPath.

tests/OpenLayers1.html

@@ -3,11 +3,15 @@
     <script src="../lib/OpenLayers.js"></script>
     <script type="text/javascript">
         function test_OpenLayers(t) {
-            t.plan(1);
+            t.plan(3);
 
             var script = document.getElementById("script");
 
             t.eq(OpenLayers._getScriptLocation(), "../", "Script location correctly detected.");
+            
+            t.ok(OpenLayers.ImgPath !== undefined, "An ImgPath property exists.");
+            
+            t.eq(OpenLayers.ImgPath, '', "The default for OpenLayers.ImgPath is the empty string.");
         }
     </script>
 </head>