Convert two tests to use async/await.

pkg/analysis_server/test/edit/fixes_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.edit.fixes;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/domain_analysis.dart';
 import 'package:analysis_server/src/edit/edit_domain.dart';
@@ skipping 16 matching lines @@
   @override
   void setUp() {
     super.setUp();
     createProject();
     ExtensionManager manager = new ExtensionManager();
     ServerPlugin plugin = new ServerPlugin();
     manager.processPlugins([plugin]);
     handler = new EditDomainHandler(server, plugin);
   }
 
-  Future test_fixUndefinedClass() {
+  Future test_fixUndefinedClass() async {
     addTestFile('''
 main() {
   Future<String> x = null;
 }
 ''');
-    return waitForTasksFinished().then((_) {
-      List<AnalysisErrorFixes> errorFixes = _getFixesAt('Future<String>');
-      expect(errorFixes, hasLength(1));
-      AnalysisError error = errorFixes[0].error;
-      expect(error.severity, AnalysisErrorSeverity.WARNING);
-      expect(error.type, AnalysisErrorType.STATIC_WARNING);
-      List<SourceChange> fixes = errorFixes[0].fixes;
-      expect(fixes, hasLength(2));
-      expect(fixes[0].message, matches('Import library'));
-      expect(fixes[1].message, matches('Create class'));
-    });
+    await waitForTasksFinished();
+    List<AnalysisErrorFixes> errorFixes = _getFixesAt('Future<String>');
+    expect(errorFixes, hasLength(1));
+    AnalysisError error = errorFixes[0].error;
+    expect(error.severity, AnalysisErrorSeverity.WARNING);
+    expect(error.type, AnalysisErrorType.STATIC_WARNING);
+    List<SourceChange> fixes = errorFixes[0].fixes;
+    expect(fixes, hasLength(2));
+    expect(fixes[0].message, matches('Import library'));
+    expect(fixes[1].message, matches('Create class'));
   }
 
-  Future test_hasFixes() {
+  Future test_hasFixes() async {
     addTestFile('''
 foo() {
   print(1)
 }
 bar() {
   print(10) print(20)
 }
 ''');
-    return waitForTasksFinished().then((_) {
-      // print(1)
-      {
-        List<AnalysisErrorFixes> errorFixes = _getFixesAt('print(1)');
-        expect(errorFixes, hasLength(1));
-        _isSyntacticErrorWithSingleFix(errorFixes[0]);
-      }
-      // print(10)
-      {
-        List<AnalysisErrorFixes> errorFixes = _getFixesAt('print(10)');
-        expect(errorFixes, hasLength(2));
-        _isSyntacticErrorWithSingleFix(errorFixes[0]);
-        _isSyntacticErrorWithSingleFix(errorFixes[1]);
-      }
-    });
+    await waitForTasksFinished();
+    // print(1)
+    {
+      List<AnalysisErrorFixes> errorFixes = _getFixesAt('print(1)');
+      expect(errorFixes, hasLength(1));
+      _isSyntacticErrorWithSingleFix(errorFixes[0]);
+    }
+    // print(10)
+    {
+      List<AnalysisErrorFixes> errorFixes = _getFixesAt('print(10)');
+      expect(errorFixes, hasLength(2));
+      _isSyntacticErrorWithSingleFix(errorFixes[0]);
+      _isSyntacticErrorWithSingleFix(errorFixes[1]);
+    }
   }
 
-  Future test_overlayOnlyFile() {
+  Future test_overlayOnlyFile() async {
     // add an overlay-only file
     {
       testCode = '''
 main() {
   print(1)
 }
 ''';
       Request request = new AnalysisUpdateContentParams(
           {testFile: new AddContentOverlay(testCode)}).toRequest('0');
       Response response =
           new AnalysisDomainHandler(server).handleRequest(request);
       expect(response, isResponseSuccess('0'));
     }
     // ask for fixes
-    return waitForTasksFinished().then((_) {
-      List<AnalysisErrorFixes> errorFixes = _getFixesAt('print(1)');
-      expect(errorFixes, hasLength(1));
-      _isSyntacticErrorWithSingleFix(errorFixes[0]);
-    });
+    await waitForTasksFinished();
+    List<AnalysisErrorFixes> errorFixes = _getFixesAt('print(1)');
+    expect(errorFixes, hasLength(1));
+    _isSyntacticErrorWithSingleFix(errorFixes[0]);
   }
 
   List<AnalysisErrorFixes> _getFixes(int offset) {
     Request request = new EditGetFixesParams(testFile, offset).toRequest('0');
     Response response = handleSuccessfulRequest(request);
     var result = new EditGetFixesResult.fromResponse(response);
     return result.fixes;
   }
 
   List<AnalysisErrorFixes> _getFixesAt(String search) {
     int offset = findOffset(search);
     return _getFixes(offset);
   }
 
   void _isSyntacticErrorWithSingleFix(AnalysisErrorFixes fixes) {
     AnalysisError error = fixes.error;
     expect(error.severity, AnalysisErrorSeverity.ERROR);
     expect(error.type, AnalysisErrorType.SYNTACTIC_ERROR);
     expect(fixes.fixes, hasLength(1));
   }
 }