--- a/storage/core/src/main/java/com/redhat/thermostat/storage/core/Connection.java	Tue Mar 19 18:16:29 2013 -0400
+++ b/storage/core/src/main/java/com/redhat/thermostat/storage/core/Connection.java	Fri Mar 08 10:40:42 2013 +0100
@@ -93,7 +93,7 @@
 
     @Override
     public String toString() {
-        return url;
+        return url == null ? "" : url;
     }
 
     /**
@@ -105,6 +105,9 @@
      * <li>{@link ConnectionStatus.FAILED_TO_CONNECT}: If the connection could
      * not be established for some reason.</li>
      * </ul>
+     * 
+     * These events are mutually exclusive. One of the two needs to be fired in
+     * any case.
      */
     public abstract void connect();
 

--- a/storage/core/src/test/java/com/redhat/thermostat/storage/core/ConnectionTest.java	Tue Mar 19 18:16:29 2013 -0400
+++ b/storage/core/src/test/java/com/redhat/thermostat/storage/core/ConnectionTest.java	Fri Mar 08 10:40:42 2013 +0100
@@ -36,6 +36,7 @@
 
 package com.redhat.thermostat.storage.core;
 
+import static org.junit.Assert.assertEquals;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.verify;
 
@@ -106,6 +107,17 @@
         verify(listener1).changed(status);
         verify(listener2).changed(status);
     }
+    
+    @Test
+    public void verifyToString() {
+        // URL == null should return empty string
+        String actual = connection.toString();
+        assertEquals("", actual);
+        String newUrl = "mongodb://someurl";
+        connection.setUrl(newUrl);
+        actual = connection.toString();
+        assertEquals(newUrl, actual);
+    }
 
 }