Fix type hierarchy when there is no element.

pkg/analysis_server/test/analysis_abstract.dart

Index: pkg/analysis_server/test/analysis_abstract.dart
diff --git a/pkg/analysis_server/test/analysis_abstract.dart b/pkg/analysis_server/test/analysis_abstract.dart
index 453e5828221997559b5f3c4dcb4c659aaf217163..9ee599f6e356ae68e9ec4596e374d6940d3db279 100644
--- a/pkg/analysis_server/test/analysis_abstract.dart
+++ b/pkg/analysis_server/test/analysis_abstract.dart
@@ -17,6 +17,7 @@ import 'package:unittest/unittest.dart';
 
 import 'mock_sdk.dart';
 import 'mocks.dart';
+import 'package:analysis_server/src/constants.dart';
 
 
 int findIdentifierLength(String search) {
@@ -44,7 +45,8 @@ class AbstractAnalysisTest {
   AnalysisServer server;
   RequestHandler handler;
 
-  Map<AnalysisService, List<String>> analysisSubscriptions = {};
+  final List<ServerErrorParams> serverErrors = <ServerErrorParams>[];
+  final Map<AnalysisService, List<String>> analysisSubscriptions = {};
 
   String projectPath = '/project';
   String testFolder = '/project/bin/';
@@ -141,6 +143,10 @@ class AbstractAnalysisTest {
   }
 
   void processNotification(Notification notification) {
+    if (notification.event == SERVER_ERROR) {
+      var params = new ServerErrorParams.fromNotification(notification);
+      serverErrors.add(params);
+    }
   }
 
   void setUp() {