refactor code completion to allow for multiple suggestion computers

pkg/analysis_services/test/completion/completion_test_util.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;
+library test.services.completion.util;
 
+import 'dart:async';
+
+import 'package:analysis_services/completion/completion_computer.dart';
 import 'package:analysis_services/completion/completion_suggestion.dart';
-import 'package:analysis_services/completion/top_level_computer.dart';
 import 'package:analysis_services/index/index.dart';
 import 'package:analysis_services/index/local_memory_index.dart';
 import 'package:analysis_services/src/search/search_engine.dart';
 import 'package:analysis_testing/abstract_single_unit.dart';
-import 'package:analysis_testing/reflective_tests.dart';
 import 'package:unittest/unittest.dart';
-import 'dart:async';
 
-main() {
-  groupSep = ' | ';
-  runReflectiveTests(TopLevelComputerTest);
-}
-
-@ReflectiveTestCase()
-class TopLevelComputerTest extends AbstractSingleUnitTest {
+class AbstractCompletionTest extends AbstractSingleUnitTest {
   Index index;
   SearchEngineImpl searchEngine;
-  TopLevelComputer computer;
+  CompletionComputer computer;
   List<CompletionSuggestion> suggestions;
 
-  test_class() {
-    addTestUnit('class B {boolean v;}');
-    return compute().then((_) {
-      assertHasResult(CompletionSuggestionKind.CLASS, 'B');
-      assertNoResult('v');
-    });
-  }
-
   void addTestUnit(String code) {
     resolveTestUnit(code);
     index.indexUnit(context, testUnit);
   }
 
   void assertHasResult(CompletionSuggestionKind kind, String completion,
       [CompletionRelevance relevance = CompletionRelevance.DEFAULT,
       bool isDeprecated = false, bool isPotential = false]) {
     var cs = suggestions.firstWhere((cs) => cs.completion == completion, orElse: () {
       var completions = suggestions.map((s) => s.completion).toList();
@@ skipping 17 matching lines @@
     return computer.compute().then((List<CompletionSuggestion> results) {
       this.suggestions = results;
     });
   }
 
   @override
   void setUp() {
     super.setUp();
     index = createLocalMemoryIndex();
     searchEngine = new SearchEngineImpl(index);
-    computer = new TopLevelComputer(searchEngine);
     verifyNoTestUnitErrors = false;
   }
 }