Integration test search.getTypeHierarchy and make some minor fixes.

pkg/analysis_server/lib/src/search/search_domain.dart

Index: pkg/analysis_server/lib/src/search/search_domain.dart
diff --git a/pkg/analysis_server/lib/src/search/search_domain.dart b/pkg/analysis_server/lib/src/search/search_domain.dart
index 9b35b4c71c8d14e657129a78f5335e49bb421cbe..a57cdffbfad8ad2332b5685ebc6aabb4a5c0221f 100644
--- a/pkg/analysis_server/lib/src/search/search_domain.dart
+++ b/pkg/analysis_server/lib/src/search/search_domain.dart
@@ -137,15 +137,20 @@ class SearchDomainHandler implements RequestHandler {
     int offset = request.getRequiredParameter(OFFSET).asInt();
     // prepare Element
     List<Element> elements = server.getElementsAtOffset(file, offset);
+    Response response = new Response(request.id);
     if (elements.isEmpty) {
-      return new Response(request.id);
+      response.setEmptyResult();

[scheglov, 2014/08/08 18:40:33]

I don't understand why we do this.
The field should be absent, and it is null by default, right?

[Paul Berry, 2014/08/08 19:23:04]

Without this call the response message would be

  {"id": ...}

But it the spec defines the response format as:

  response: {
    "id": String
    "error": optional Error
    "result": {
      "hierarchyItems": optional List<TypeHierarchyItem>
    }
  }

which implies that the response should be:

  {"id": ..., "result": {}}

The call to setEmptyResult() ensures that "result": {} is present.

+      return response;
     }
     Element element = elements.first;
     // prepare type hierarchy
     TypeHierarchyComputer computer = new TypeHierarchyComputer(searchEngine);
     computer.compute(element).then((List<TypeHierarchyItem> items) {
-      Response response = new Response(request.id);
-      response.setResult(HIERARCHY_ITEMS, objectToJson(items));
+      if (items != null) {
+        response.setResult(HIERARCHY_ITEMS, objectToJson(items));
+      } else {
+        response.setEmptyResult();

[scheglov, 2014/08/08 18:40:33]

Same here.

+      }
       server.sendResponse(response);
     });
     // delay response