Better JUnit assert message.

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/httpasyncclient/trunk@1697597 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/httpasyncclient/src/test/java/org/apache/http/nio/client/integration/TestHttpAsyncPrematureTermination.java b/httpasyncclient/src/test/java/org/apache/http/nio/client/integration/TestHttpAsyncPrematureTermination.java
index f0a6b26..34fad27 100644
--- a/httpasyncclient/src/test/java/org/apache/http/nio/client/integration/TestHttpAsyncPrematureTermination.java
+++ b/httpasyncclient/src/test/java/org/apache/http/nio/client/integration/TestHttpAsyncPrematureTermination.java
@@ -306,7 +306,7 @@
             future.get();
             Assert.fail();
         } catch (ExecutionException e) {
-            Assert.assertTrue(e.getCause() instanceof UnknownHostException);
+            Assert.assertTrue(e.toString(), e.getCause() instanceof UnknownHostException);
         }
         this.connMgr.shutdown(1000);