include lower relevance suggestions only if they are already cached

pkg/analysis_server/test/services/completion/imported_computer_test.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library test.services.completion.toplevel;
 
 import 'package:analysis_server/src/protocol.dart';
 import 'package:analysis_server/src/services/completion/completion_manager.dart';
 import 'package:analysis_server/src/services/completion/dart_completion_cache.dart';
 import 'package:analysis_server/src/services/completion/dart_completion_manager.dart';
@@ skipping 81 matching lines @@
         isCached(cache.otherImportedSuggestions, completion)) {
       fail('expected $completion NOT to be cached');
     }
   }
 
   bool isCached(List<CompletionSuggestion> suggestions, String completion) =>
       suggestions.any((CompletionSuggestion s) => s.completion == completion);
 
   @override
   void setUpComputer() {
-    computer = new ImportedComputer();
+    computer = new ImportedComputer(shouldWaitForLowPrioritySuggestions: true);
   }
 
   @override
   test_ArgumentList() {
     return super.test_ArgumentList().then((_) {
       expect(request.cache.importKey, "import '/libA.dart';");
     });
   }
 
   @override
@@ skipping 25 matching lines @@
   test_Block_inherited_imported() {
     return super.test_Block_inherited_imported().then((_) {
       assertCached('E');
       assertCached('F');
       assertNotCached('e1');
       assertNotCached('i2');
       assertNotCached('m1');
     });
   }
 }