Test that the ConcurrentSessioncontrollerImpl implements ApplicationListener. This is critical and was left out once.

core/src/test/java/org/acegisecurity/providers/ConcurrentSessionControllerImplTests.java

@@ -22,6 +22,7 @@ import net.sf.acegisecurity.providers.dao.User;
 import net.sf.acegisecurity.ui.WebAuthenticationDetails;
 import net.sf.acegisecurity.ui.session.HttpSessionCreatedEvent;
 import net.sf.acegisecurity.ui.session.HttpSessionDestroyedEvent;
+import org.springframework.context.ApplicationListener;
 
 import java.security.Principal;
 
@@ -241,4 +242,8 @@ public class ConcurrentSessionControllerImplTests extends TestCase {
         target.beforeAuthentication(auth);
         target.afterAuthentication(auth, auth);
     }
+
+    public void testImplementsApplicationListener() throws Exception {
+        assertTrue("This class must implement ApplicationListener, and at one point it didn't.", target instanceof ApplicationListener);
+    }
 }