Switch analysis_server to use 'package:test'.

pkg/analysis_server/test/integration/analysis/error_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.integration.analysis.error;
 
 import 'package:analysis_server/plugin/protocol/protocol.dart';
+import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
-import 'package:unittest/unittest.dart';
 
 import '../../utils.dart';
 import '../integration_tests.dart';
 
 main() {
   initializeTestEnvironment();
-  defineReflectiveTests(AnalysisErrorIntegrationTest);
+  defineReflectiveSuite(() {
+    defineReflectiveTests(AnalysisErrorIntegrationTest);
+  });
 }
 
 @reflectiveTest
 class AnalysisErrorIntegrationTest
     extends AbstractAnalysisServerIntegrationTest {
   test_detect_simple_error() {
     String pathname = sourcePath('test.dart');
     writeFile(
         pathname,
         '''
@@ skipping 62 matching lines @@
 ''');
     await sendAnalysisUpdateOptions(
         new AnalysisOptions()..enableSuperMixins = true);
     standardAnalysisSetup();
     await analysisFinished;
     expect(currentAnalysisErrors[pathname], isList);
     List<AnalysisError> errors = currentAnalysisErrors[pathname];
     expect(errors, isEmpty);
   }
 }