Extract constants into separate libarary.

pkg/analysis_server/test/socket_server_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.socket.server;
 
 import 'dart:async';
 
 import 'mocks.dart';
 
-import 'package:analysis_server/src/analysis_server.dart';
-import 'package:analysis_server/src/domain_server.dart';
+import 'package:analysis_server/src/constants.dart';
 import 'package:analysis_server/src/protocol.dart';
 import 'package:analysis_server/src/socket_server.dart';
 import 'package:unittest/unittest.dart';
 
 main() {
   group('SocketServer', () {
     test('createAnalysisServer_successful',
         SocketServerTest.createAnalysisServer_successful);
     test('createAnalysisServer_alreadyStarted',
         SocketServerTest.createAnalysisServer_alreadyStarted);
   });
 }
 
 class SocketServerTest {
   static Future createAnalysisServer_successful() {
     SocketServer server = new SocketServer();
     MockServerChannel channel = new MockServerChannel();
     server.createAnalysisServer(channel);
     channel.expectMsgCount(notificationCount: 1);
-    expect(channel.notificationsReceived[0].event, equals(
-        AnalysisServer.CONNECTED_NOTIFICATION));
+    expect(channel.notificationsReceived[0].event, NOTIFICATION_CONNECTED);
     expect(channel.notificationsReceived[0].params, isEmpty);
-    return channel.sendRequest(new Request('0',
-        ServerDomainHandler.SHUTDOWN_METHOD)).then((Response response) {
+    return channel.sendRequest(
+        new Request('0', METHOD_SHUTDOWN)
+    ).then((Response response) {
       expect(response.id, equals('0'));
       expect(response.error, isNull);
       channel.expectMsgCount(responseCount: 1, notificationCount: 1);
     });
   }
 
   static void createAnalysisServer_alreadyStarted() {
     SocketServer server = new SocketServer();
     MockServerChannel channel1 = new MockServerChannel();
     MockServerChannel channel2 = new MockServerChannel();
     server.createAnalysisServer(channel1);
-    expect(channel1.notificationsReceived[0].event, equals(
-        AnalysisServer.CONNECTED_NOTIFICATION));
+    expect(channel1.notificationsReceived[0].event, NOTIFICATION_CONNECTED);
     expect(channel1.notificationsReceived[0].params, isEmpty);
     server.createAnalysisServer(channel2);
     channel1.expectMsgCount(notificationCount: 1);
     channel2.expectMsgCount(responseCount: 1);
     expect(channel2.responsesReceived[0].id, equals(''));
     expect(channel2.responsesReceived[0].error, isNotNull);
     expect(channel2.responsesReceived[0].error.code, equals(
         RequestError.CODE_SERVER_ALREADY_STARTED));
-    channel2.sendRequest(new Request('0', ServerDomainHandler.SHUTDOWN_METHOD)
-        ).then((Response response) {
+    channel2.sendRequest(new Request('0', METHOD_SHUTDOWN)).then((Response response) {
       expect(response.id, equals('0'));
       expect(response.error, isNotNull);
       expect(response.error.code, equals(
           RequestError.CODE_SERVER_ALREADY_STARTED));
       channel2.expectMsgCount(responseCount: 2);
     });
   }
 }