Don't show broken image when no test results are available

src/main/java/hudson/plugins/fitnesse/FitnesseProjectAction.java

@@ -33,11 +33,21 @@ public String getUrlName() {
         return "fitnesse";
     }
 
+    /**
+     * Used in floatingBox.jelly
+     */
+    public boolean hasTrend() {
+    	return getLatestResults() != null;
+    }
+
     /**
      * Used in floatingBox.jelly
      */
     public History getTrend() {
     	FitnesseResultsAction latestResults = getLatestResults();
+    	if (latestResults == null) {
+    		return null;
+    	}
     	FitnesseResults result = latestResults.getResult();
 		return new History(result,500,200);
     }

src/main/resources/hudson/plugins/fitnesse/FitnesseProjectAction/floatingBox.jelly

@@ -1,10 +1,13 @@
 <j:jelly xmlns:j="jelly:core" xmlns:st="jelly:stapler"
 	xmlns:d="jelly:define" xmlns:l="/lib/layout" xmlns:t="/lib/hudson"
 	xmlns:f="/lib/form" xmlns:i="jelly:fmt">
+
+    <j:if test="${action.hasTrend()}">
       <div class="test-trend-caption">
         ${%FitNesse Results Trend}
       </div>
 	  <div>
         <img src="fitnesse/trend/countGraph/png" lazymap="fitnesse/trend/countGraph/map" alt="[FitNesse results trend chart]"/>
       </div>
+    </j:if>
 </j:jelly>