Rework the replay test to be more correct

pkg/analysis_server/test/stress/utilities/server.dart

Index: pkg/analysis_server/test/stress/utilities/server.dart
diff --git a/pkg/analysis_server/test/stress/utilities/server.dart b/pkg/analysis_server/test/stress/utilities/server.dart
index ee52fdd6551ecd7369699b19ed6de443218225d6..cc96aca88af5f5aa892ee70b2ba7feb89b65ba3f 100644
--- a/pkg/analysis_server/test/stress/utilities/server.dart
+++ b/pkg/analysis_server/test/stress/utilities/server.dart
@@ -3,18 +3,24 @@
 // BSD-style license that can be found in the LICENSE file.
 
 /**
- * Support for interacting with an analysis server running in a separate
+ * Support for interacting with an analysis server that is running in a separate
  * process.
  */
-library analysis_server.test.stress.utilities.server;
-
 import 'dart:async';
 import 'dart:collection';
+import 'dart:convert' hide JsonDecoder;
+import 'dart:io';
+import 'dart:math' as math;
 
 import 'package:analysis_server/plugin/protocol/protocol.dart';
+import 'package:path/path.dart' as path;
+
+import 'logger.dart';
 
-import '../../integration/integration_test_methods.dart';
-import '../../integration/integration_tests.dart' as base;
+/**
+ * Return the current time expressed as milliseconds since the epoch.
+ */
+int get currentTime => new DateTime.now().millisecondsSinceEpoch;
 
 /**
  * ???
@@ -59,36 +65,222 @@ class ErrorMap {
 }
 
 /**
- * An interface for starting and communicating with an analysis server running
- * in a separate process.
+ * Data that has been collected about a request sent to the server.
+ */
+class RequestData {
+  /**
+   * The unique id of the request.
+   */
+  final String id;
+
+  /**
+   * The method that was requested.
+   */
+  final String method;
+
+  /**
+   * The request parameters.
+   */
+  final Map<String, dynamic> params;
+
+  /**
+   * The time at which the request was sent.
+   */
+  final int requestTime;
+
+  /**
+   * The time at which the response was received, or `null` if no response has
+   * been received.
+   */
+  int responseTime = null;
+
+  /**
+   * The response that was received.
+   */
+  Response _response;
+
+  /**
+   * The completer that will be completed when a response is received.
+   */
+  Completer<Response> _responseCompleter;
+
+  /**
+   * Initialize a newly created set of request data.
+   */
+  RequestData(this.id, this.method, this.params, this.requestTime);
+
+  /**
+   * Return the number of milliseconds that elapsed betwee the request and the
+   * response. This getter assumes that the response was received.
+   */
+  int get elapsedTime => responseTime - requestTime;
+
+  /**
+   * Return a future that will complete when a response is received.
+   */
+  Future<Response> get respondedTo {
+    if (_response != null) {
+      return new Future.value(_response);
+    }
+    if (_responseCompleter == null) {
+      _responseCompleter = new Completer<Response>();
+    }
+    return _responseCompleter.future;
+  }
+
+  /**
+   * Record that the given [response] was received.
+   */
+  void recordResponse(Response response) {
+    if (_response != null) {
+      stdout.writeln(
+          'Received a second response to a $method request (id = $id)');
+      return;
+    }
+    responseTime = currentTime;
+    _response = response;
+    if (_responseCompleter != null) {
+      _responseCompleter.complete(response);
+      _responseCompleter = null;
+    }
+  }
+}
+
+/**
+ * A utility for starting and communicating with an analysis server that is
+ * running in a separate process.
  */
-class Server extends base.Server with IntegrationTestMixin {
+class Server {
+  /**
+   * The label used for communications from the client.
+   */
+  static const String fromClient = 'client';
+
+  /**
+   * The label used for normal communications from the server.
+   */
+  static const String fromServer = 'server';
+
+  /**
+   * The label used for output written by the server on [fromStderr].
+   */
+  static const String fromStderr = 'stderr';
+
+  /**
+   * The logger to which the communications log should be written, or `null` if
+   * the log should not be written.
+   */
+  final Logger logger;
+
+  /**
+   * The process in which the server is running, or `null` if the server hasn't
+   * been started yet.
+   */
+  Process _process = null;
+
+  /**
+   * Number that should be used to compute the 'id' to send in the next command
+   * sent to the server.
+   */
+  int _nextId = 0;
+
+  /**
+   * The analysis roots that are included.
+   */
+  List<String> _analysisRootIncludes = <String>[];
+
+  /**
+   * The analysis roots that are excluded.
+   */
+  List<String> _analysisRootExcludes = <String>[];
+
   /**
    * A list containing the paths of files for which an overlay has been created.
    */
   List<String> filesWithOverlays = <String>[];
 
   /**
+   * The files that the server reported as being analyzed.
+   */
+  List<String> _analyzedFiles = <String>[];
+
+  /**
    * A mapping from the absolute paths of files to the most recent set of errors
    * received for that file.
    */
   ErrorMap _errorMap = new ErrorMap();
 
   /**
+   * The completer that will be completed the next time a 'server.status'
+   * notification is received from the server with 'analyzing' set to false.
+   */
+  Completer<Null> _analysisFinishedCompleter;
+
+  /**
+   * The completer that will be completed the next time a 'server.connected'
+   * notification is received from the server.
+   */
+  Completer<Null> _serverConnectedCompleter;
+
+  /**
+   * A table mapping the ids of requests that have been sent to the server to
+   * data about those requests.
+   */
+  final Map<String, RequestData> _requestDataMap = <String, RequestData>{};
+
+  /**
+   * A table mapping the number of times a request whose 'event' is equal to the
+   * key was sent to the server.
+   */
+  final Map<String, int> _notificationCountMap = <String, int>{};
+
+  /**
    * Initialize a new analysis server. The analysis server is not running and
    * must be started using [start].
+   *
+   * If a [logger] is provided, the communications between the client (this
+   * test) and the server will be written to it.
+   */
+  Server({this.logger = null});
+
+  /**
+   * Return a future that will complete when a 'server.status' notification is
+   * received from the server with 'analyzing' set to false.
+   *
+   * The future will only be completed by 'server.status' notifications that are
+   * received after this function call, so it is safe to use this getter
+   * multiple times in one test; each time it is used it will wait afresh for
+   * analysis to finish.
    */
-  Server() {
-    initializeInttestMixin();
-    onAnalysisErrors.listen(_recordErrors);
+  Future get analysisFinished {
+    if (_analysisFinishedCompleter == null) {
+      _analysisFinishedCompleter = new Completer();
+    }
+    return _analysisFinishedCompleter.future;
   }
 
   /**
    * Return a list of the paths of files that are currently being analyzed.
    */
   List<String> get analyzedDartFiles {
-    // TODO(brianwilkerson) Implement this.
-    return <String>[];
+    bool isAnalyzed(String filePath) {
+      // TODO(brianwilkerson) This should use the path package to determine
+      // inclusion, and needs to take exclusions into account.
+      for (String includedRoot in _analysisRootIncludes) {
+        if (filePath.startsWith(includedRoot)) {
+          return true;
+        }
+      }
+      return false;
+    }
+
+    List<String> analyzedFiles = <String>[];
+    for (String filePath in _analyzedFiles) {
+      if (filePath.endsWith('.dart') && isAnalyzed(filePath)) {
+        analyzedFiles.add(filePath);
+      }
+    }
+    return analyzedFiles;
   }
 
   /**
@@ -98,9 +290,6 @@ class Server extends base.Server with IntegrationTestMixin {
    */
   ErrorMap get errorMap => new ErrorMap.from(_errorMap);
 
-  @override
-  base.Server get server => this;
-
   /**
    * Compute a mapping from each of the file paths in the given list of
    * [filePaths] to the list of errors in the file at that path.
@@ -109,9 +298,13 @@ class Server extends base.Server with IntegrationTestMixin {
     ErrorMap errorMap = new ErrorMap();
     List<Future> futures = <Future>[];
     for (String filePath in filePaths) {
-      futures.add(sendAnalysisGetErrors(filePath)
-          .then((AnalysisGetErrorsResult result) {
-        errorMap[filePath] = result.errors;
+      RequestData requestData = sendAnalysisGetErrors(filePath);
+      futures.add(requestData.respondedTo.then((Response response) {
+        if (response.result != null) {
+          AnalysisGetErrorsResult result =
+              new AnalysisGetErrorsResult.fromResponse(response);
+          errorMap[filePath] = result.errors;
+        }
       }));
     }
     await Future.wait(futures);
@@ -119,19 +312,168 @@ class Server extends base.Server with IntegrationTestMixin {
   }
 
   /**
+   * Print information about the communications with the server.
+   */
+  void printStatistics() {
+    void writeSpaces(int count) {
+      for (int i = 0; i < count; i++) {
+        stdout.write(' ');
+      }
+    }
+
+    //
+    // Print information about the requests that were sent.
+    //
+    stdout.writeln('Request Counts');
+    if (_requestDataMap.isEmpty) {
+      stdout.writeln('  none');
+    } else {
+      Map<String, List<RequestData>> requestsByMethod =
+          <String, List<RequestData>>{};
+      _requestDataMap.values.forEach((RequestData requestData) {
+        requestsByMethod
+            .putIfAbsent(requestData.method, () => <RequestData>[])
+            .add(requestData);
+      });
+      List<String> keys = requestsByMethod.keys.toList();
+      keys.sort();
+      int maxCount = requestsByMethod.values
+          .fold(0, (int count, List<RequestData> list) => count + list.length);
+      int countWidth = maxCount.toString().length;
+      for (String key in keys) {
+        List<RequestData> requests = requestsByMethod[key];
+        int noResponseCount = 0;
+        int responseCount = 0;
+        int minTime = -1;
+        int maxTime = -1;
+        int totalTime = 0;
+        requests.forEach((RequestData data) {
+          if (data.responseTime == null) {
+            noResponseCount++;
+          } else {
+            responseCount++;
+            int time = data.elapsedTime;
+            minTime = minTime < 0 ? time : math.min(minTime, time);
+            maxTime = math.max(maxTime, time);
+            totalTime += time;
+          }
+        });
+        String count = requests.length.toString();
+        writeSpaces(countWidth - count.length);
+        stdout.write('  ');
+        stdout.write(count);
+        stdout.write(' - ');
+        stdout.write(key);
+        if (noResponseCount > 0) {
+          stdout.write(', ');
+          stdout.write(noResponseCount);
+          stdout.write(' with no response');
+        }
+        if (maxTime >= 0) {
+          stdout.write(' (');
+          stdout.write(minTime);
+          stdout.write(', ');
+          stdout.write(totalTime / responseCount);
+          stdout.write(', ');
+          stdout.write(maxTime);
+          stdout.write(')');
+        }
+        stdout.writeln();
+      }
+    }
+    //
+    // Print information about the notifications that were received.
+    //
+    stdout.writeln();
+    stdout.writeln('Notification Counts');
+    if (_notificationCountMap.isEmpty) {
+      stdout.writeln('  none');
+    } else {
+      List<String> keys = _notificationCountMap.keys.toList();
+      keys.sort();
+      int maxCount = _notificationCountMap.values.fold(0, math.max);
+      int countWidth = maxCount.toString().length;
+      for (String key in keys) {
+        String count = _notificationCountMap[key].toString();
+        writeSpaces(countWidth - count.length);
+        stdout.write('  ');
+        stdout.write(count);
+        stdout.write(' - ');
+        stdout.writeln(key);
+      }
+    }
+  }
+
+  /**
    * Remove any existing overlays.
    */
-  Future<AnalysisUpdateContentResult> removeAllOverlays() {
+  void removeAllOverlays() {
     Map<String, dynamic> files = new HashMap<String, dynamic>();
     for (String path in filesWithOverlays) {
       files[path] = new RemoveContentOverlay();
     }
-    return sendAnalysisUpdateContent(files);
+    sendAnalysisUpdateContent(files);
+  }
+
+  RequestData sendAnalysisGetErrors(String file) {
+    var params = new AnalysisGetErrorsParams(file).toJson();
+    return _send("analysis.getErrors", params);
+  }
+
+  RequestData sendAnalysisGetHover(String file, int offset) {
+    var params = new AnalysisGetHoverParams(file, offset).toJson();
+    return _send("analysis.getHover", params);
+  }
+
+  RequestData sendAnalysisGetLibraryDependencies() {
+    return _send("analysis.getLibraryDependencies", null);
+  }
+
+  RequestData sendAnalysisGetNavigation(String file, int offset, int length) {
+    var params = new AnalysisGetNavigationParams(file, offset, length).toJson();
+    return _send("analysis.getNavigation", params);
+  }
+
+  RequestData sendAnalysisGetReachableSources(String file) {
+    var params = new AnalysisGetReachableSourcesParams(file).toJson();
+    return _send("analysis.getReachableSources", params);
+  }
+
+  void sendAnalysisReanalyze({List<String> roots}) {
+    var params = new AnalysisReanalyzeParams(roots: roots).toJson();
+    _send("analysis.reanalyze", params);
+  }
+
+  void sendAnalysisSetAnalysisRoots(
+      List<String> included, List<String> excluded,
+      {Map<String, String> packageRoots}) {
+    _analysisRootIncludes = included;
+    _analysisRootExcludes = excluded;
+    var params = new AnalysisSetAnalysisRootsParams(included, excluded,
+            packageRoots: packageRoots)
+        .toJson();
+    _send("analysis.setAnalysisRoots", params);
+  }
+
+  void sendAnalysisSetGeneralSubscriptions(
+      List<GeneralAnalysisService> subscriptions) {
+    var params =
+        new AnalysisSetGeneralSubscriptionsParams(subscriptions).toJson();
+    _send("analysis.setGeneralSubscriptions", params);
+  }
+
+  void sendAnalysisSetPriorityFiles(List<String> files) {
+    var params = new AnalysisSetPriorityFilesParams(files).toJson();
+    _send("analysis.setPriorityFiles", params);
+  }
+
+  void sendAnalysisSetSubscriptions(
+      Map<AnalysisService, List<String>> subscriptions) {
+    var params = new AnalysisSetSubscriptionsParams(subscriptions).toJson();
+    _send("analysis.setSubscriptions", params);
   }
 
-  @override
-  Future<AnalysisUpdateContentResult> sendAnalysisUpdateContent(
-      Map<String, dynamic> files) {
+  void sendAnalysisUpdateContent(Map<String, dynamic> files) {
     files.forEach((String path, dynamic overlay) {
       if (overlay is AddContentOverlay) {
         filesWithOverlays.add(path);
@@ -139,14 +481,482 @@ class Server extends base.Server with IntegrationTestMixin {
         filesWithOverlays.remove(path);
       }
     });
-    return super.sendAnalysisUpdateContent(files);
+    var params = new AnalysisUpdateContentParams(files).toJson();
+    _send('analysis.updateContent', params);
+  }
+
+  void sendAnalysisUpdateOptions(AnalysisOptions options) {
+    var params = new AnalysisUpdateOptionsParams(options).toJson();
+    _send("analysis.updateOptions", params);
+  }
+
+  void sendCompletionGetSuggestions(String file, int offset) {
+    var params = new CompletionGetSuggestionsParams(file, offset).toJson();
+    _send("completion.getSuggestions", params);
+  }
+
+  RequestData sendDiagnosticGetDiagnostics() {
+    return _send("diagnostic.getDiagnostics", null);
+  }
+
+  RequestData sendEditFormat(
+      String file, int selectionOffset, int selectionLength,
+      {int lineLength}) {
+    var params = new EditFormatParams(file, selectionOffset, selectionLength,
+            lineLength: lineLength)
+        .toJson();
+    return _send("edit.format", params);
+  }
+
+  RequestData sendEditGetAssists(String file, int offset, int length) {
+    var params = new EditGetAssistsParams(file, offset, length).toJson();
+    return _send("edit.getAssists", params);
+  }
+
+  RequestData sendEditGetAvailableRefactorings(
+      String file, int offset, int length) {
+    var params =
+        new EditGetAvailableRefactoringsParams(file, offset, length).toJson();
+    return _send("edit.getAvailableRefactorings", params);
+  }
+
+  RequestData sendEditGetFixes(String file, int offset) {
+    var params = new EditGetFixesParams(file, offset).toJson();
+    return _send("edit.getFixes", params);
+  }
+
+  RequestData sendEditGetRefactoring(RefactoringKind kind, String file,
+      int offset, int length, bool validateOnly,
+      {RefactoringOptions options}) {
+    var params = new EditGetRefactoringParams(
+            kind, file, offset, length, validateOnly,
+            options: options)
+        .toJson();
+    return _send("edit.getRefactoring", params);
+  }
+
+  RequestData sendEditOrganizeDirectives(String file) {
+    var params = new EditOrganizeDirectivesParams(file).toJson();
+    return _send("edit.organizeDirectives", params);
+  }
+
+  RequestData sendEditSortMembers(String file) {
+    var params = new EditSortMembersParams(file).toJson();
+    return _send("edit.sortMembers", params);
+  }
+
+  RequestData sendExecutionCreateContext(String contextRoot) {
+    var params = new ExecutionCreateContextParams(contextRoot).toJson();
+    return _send("execution.createContext", params);
+  }
+
+  RequestData sendExecutionDeleteContext(String id) {
+    var params = new ExecutionDeleteContextParams(id).toJson();
+    return _send("execution.deleteContext", params);
+  }
+
+  RequestData sendExecutionMapUri(String id, {String file, String uri}) {
+    var params = new ExecutionMapUriParams(id, file: file, uri: uri).toJson();
+    return _send("execution.mapUri", params);
+  }
+
+  RequestData sendExecutionSetSubscriptions(
+      List<ExecutionService> subscriptions) {
+    var params = new ExecutionSetSubscriptionsParams(subscriptions).toJson();
+    return _send("execution.setSubscriptions", params);
+  }
+
+  void sendSearchFindElementReferences(
+      String file, int offset, bool includePotential) {
+    var params =
+        new SearchFindElementReferencesParams(file, offset, includePotential)
+            .toJson();
+    _send("search.findElementReferences", params);
+  }
+
+  void sendSearchFindMemberDeclarations(String name) {
+    var params = new SearchFindMemberDeclarationsParams(name).toJson();
+    _send("search.findMemberDeclarations", params);
+  }
+
+  void sendSearchFindMemberReferences(String name) {
+    var params = new SearchFindMemberReferencesParams(name).toJson();
+    _send("search.findMemberReferences", params);
+  }
+
+  void sendSearchFindTopLevelDeclarations(String pattern) {
+    var params = new SearchFindTopLevelDeclarationsParams(pattern).toJson();
+    _send("search.findTopLevelDeclarations", params);
+  }
+
+  void sendSearchGetTypeHierarchy(String file, int offset, {bool superOnly}) {
+    var params =
+        new SearchGetTypeHierarchyParams(file, offset, superOnly: superOnly)
+            .toJson();
+    _send("search.getTypeHierarchy", params);
+  }
+
+  RequestData sendServerGetVersion() {
+    return _send("server.getVersion", null);
+  }
+
+  void sendServerSetSubscriptions(List<ServerService> subscriptions) {
+    var params = new ServerSetSubscriptionsParams(subscriptions).toJson();
+    _send("server.setSubscriptions", params);
+  }
+
+  void sendServerShutdown() {
+    _send("server.shutdown", null);
+  }
+
+  /**
+   * Start the server and listen for communications from it.
+   *
+   * If [checked] is `true`, the server's VM will be running in checked mode.
+   *
+   * If [debugServer] is `true`, the server will be started with "--debug",
+   * allowing a debugger to be attached.
+   *
+   * If [diagnosticPort] is not `null`, the server will serve status pages to
+   * the specified port.
+   *
+   * If [enableNewAnalysisDriver] is `true`, the server will use the new
+   * analysis driver.
+   *
+   * If [profileServer] is `true`, the server will be started with "--observe"
+   * and "--pause-isolates-on-exit", allowing the observatory to be used.
+   *
+   * If [useAnalysisHighlight2] is `true`, the server will use the new highlight
+   * APIs.
+   */
+  Future<Null> start(
+      {bool checked: true,
+      bool debugServer: false,
+      int diagnosticPort,
+      bool enableNewAnalysisDriver: false,
+      bool profileServer: false,
+      String sdkPath,
+      int servicesPort,
+      bool useAnalysisHighlight2: false}) async {
+    if (_process != null) {
+      throw new Exception('Process already started');
+    }
+    String dartBinary = Platform.executable;
+    String rootDir =
+        _findRoot(Platform.script.toFilePath(windows: Platform.isWindows));
+    String serverPath =
+        path.normalize(path.join(rootDir, 'bin', 'server.dart'));
+    List<String> arguments = [];
+    //
+    // Add VM arguments.
+    //
+    if (debugServer) {
+      arguments.add('--debug');
+    }
+    if (profileServer) {
+      if (servicesPort == null) {
+        arguments.add('--observe');
+      } else {
+        arguments.add('--observe=$servicesPort');
+      }
+      arguments.add('--pause-isolates-on-exit');
+    } else if (servicesPort != null) {
+      arguments.add('--enable-vm-service=$servicesPort');
+    }
+    if (Platform.packageRoot != null) {
+      arguments.add('--package-root=${Platform.packageRoot}');
+    }
+    if (Platform.packageConfig != null) {
+      arguments.add('--packages=${Platform.packageConfig}');
+    }
+    if (checked) {
+      arguments.add('--checked');
+    }
+    //
+    // Add the server executable.
+    //
+    arguments.add(serverPath);
+    //
+    // Add server arguments.
+    //
+    if (diagnosticPort != null) {
+      arguments.add('--port');
+      arguments.add(diagnosticPort.toString());
+    }
+    if (sdkPath != null) {
+      arguments.add('--sdk=$sdkPath');
+    }
+    if (useAnalysisHighlight2) {
+      arguments.add('--useAnalysisHighlight2');
+    }
+    if (enableNewAnalysisDriver) {
+      arguments.add('--enable-new-analysis-driver');
+    }
+//    stdout.writeln('Launching $serverPath');
+//    stdout.writeln('$dartBinary ${arguments.join(' ')}');
+    _process = await Process.start(dartBinary, arguments);
+    _process.exitCode.then((int code) {
+      if (code != 0) {
+        throw new StateError('Server terminated with exit code $code');
+      }
+    });
+    _listenToOutput();
+    _serverConnectedCompleter = new Completer();
+    return _serverConnectedCompleter.future;
+  }
+
+  /**
+   * Find the root directory of the analysis_server package by proceeding
+   * upward to the 'test' dir, and then going up one more directory.
+   */
+  String _findRoot(String pathname) {
+    while (!['benchmark', 'test'].contains(path.basename(pathname))) {
+      String parent = path.dirname(pathname);
+      if (parent.length >= pathname.length) {
+        throw new Exception("Can't find root directory");
+      }
+      pathname = parent;
+    }
+    return path.dirname(pathname);
   }
 
   /**
-   * Record the errors in the given [params].
+   * Handle a [notification] received from the server.
    */
-  void _recordErrors(AnalysisErrorsParams params) {
-    _errorMap[params.file] = params.errors;
+  void _handleNotification(Notification notification) {
+    switch (notification.event) {
+      case "server.connected":
+//        new ServerConnectedParams.fromNotification(notification);
+        _serverConnectedCompleter.complete(null);
+        break;
+      case "server.error":
+//        new ServerErrorParams.fromNotification(notification);
+        throw new StateError('Server error: ${notification.toJson()}');
+        break;
+      case "server.status":
+        if (_analysisFinishedCompleter != null) {
+          ServerStatusParams params =
+              new ServerStatusParams.fromNotification(notification);
+          var analysis = params.analysis;
+          if (analysis != null && !analysis.isAnalyzing) {
+            _analysisFinishedCompleter.complete(null);
+          }
+        }
+        break;
+      case "analysis.analyzedFiles":
+        AnalysisAnalyzedFilesParams params =
+            new AnalysisAnalyzedFilesParams.fromNotification(notification);
+        _analyzedFiles = params.directories;
+        break;
+      case "analysis.errors":
+        AnalysisErrorsParams params =
+            new AnalysisErrorsParams.fromNotification(notification);
+        _errorMap.pathMap[params.file] = params.errors;
+        break;
+      case "analysis.flushResults":
+//        new AnalysisFlushResultsParams.fromNotification(notification);
+        _errorMap.pathMap.clear();
+        break;
+      case "analysis.folding":
+//        new AnalysisFoldingParams.fromNotification(notification);
+        break;
+      case "analysis.highlights":
+//        new AnalysisHighlightsParams.fromNotification(notification);
+        break;
+      case "analysis.implemented":
+//        new AnalysisImplementedParams.fromNotification(notification);
+        break;
+      case "analysis.invalidate":
+//        new AnalysisInvalidateParams.fromNotification(notification);
+        break;
+      case "analysis.navigation":
+//        new AnalysisNavigationParams.fromNotification(notification);
+        break;
+      case "analysis.occurrences":
+//        new AnalysisOccurrencesParams.fromNotification(notification);
+        break;
+      case "analysis.outline":
+//        new AnalysisOutlineParams.fromNotification(notification);
+        break;
+      case "analysis.overrides":
+//        new AnalysisOverridesParams.fromNotification(notification);
+        break;
+      case "completion.results":
+//        new CompletionResultsParams.fromNotification(notification);
+        break;
+      case "search.results":
+//        new SearchResultsParams.fromNotification(notification);
+        break;
+      case "execution.launchData":
+//        new ExecutionLaunchDataParams.fromNotification(notification);
+        break;
+      default:
+        throw new StateError(
+            'Unhandled notification: ${notification.toJson()}');
+    }
+  }
+
+  /**
+   * Handle a [response] received from the server.
+   */
+  void _handleResponse(Response response) {
+    String id = response.id.toString();
+    RequestData requestData = _requestDataMap[id];
+    requestData.recordResponse(response);
+//    switch (requestData.method) {
+//      case "analysis.getErrors":
+//        break;
+//      case "analysis.getHover":
+//        break;
+//      case "analysis.getLibraryDependencies":
+//        break;
+//      case "analysis.getNavigation":
+//        break;
+//      case "analysis.getReachableSources":
+//        break;
+//      case "analysis.reanalyze":
+//        break;
+//      case "analysis.setAnalysisRoots":
+//        break;
+//      case "analysis.setGeneralSubscriptions":
+//        break;
+//      case "analysis.setPriorityFiles":
+//        break;
+//      case "analysis.setSubscriptions":
+//        break;
+//      case 'analysis.updateContent':
+//        break;
+//      case "analysis.updateOptions":
+//        break;
+//      case "completion.getSuggestions":
+//        break;
+//      case "diagnostic.getDiagnostics":
+//        break;
+//      case "edit.format":
+//        break;
+//      case "edit.getAssists":
+//        break;
+//      case "edit.getAvailableRefactorings":
+//        break;
+//      case "edit.getFixes":
+//        break;
+//      case "edit.getRefactoring":
+//        break;
+//      case "edit.organizeDirectives":
+//        break;
+//      case "edit.sortMembers":
+//        break;
+//      case "execution.createContext":
+//        break;
+//      case "execution.deleteContext":
+//        break;
+//      case "execution.mapUri":
+//        break;
+//      case "execution.setSubscriptions":
+//        break;
+//      case "search.findElementReferences":
+//        break;
+//      case "search.findMemberDeclarations":
+//        break;
+//      case "search.findMemberReferences":
+//        break;
+//      case "search.findTopLevelDeclarations":
+//        break;
+//      case "search.getTypeHierarchy":
+//        break;
+//      case "server.getVersion":
+//        break;
+//      case "server.setSubscriptions":
+//        break;
+//      case "server.shutdown":
+//        break;
+//      default:
+//        throw new StateError('Unhandled response: ${response.toJson()}');
+//    }
+  }
+
+  /**
+   * Handle a [line] of input read from stderr.
+   */
+  void _handleStdErr(String line) {
+    String trimmedLine = line.trim();
+    logger?.log(fromStderr, '$trimmedLine');
+    throw new StateError('Message received on stderr: "$trimmedLine"');
+  }
+
+  /**
+   * Handle a [line] of input read from stdout.
+   */
+  void _handleStdOut(String line) {
+    /**
+     * Cast the given [value] to a Map, or throw an [ArgumentError] if the value
+     * cannot be cast.
+     */
+    Map asMap(Object value) {
+      if (value is Map) {
+        return value;
+      }
+      throw new ArgumentError('Expected a Map, found a ${value.runtimeType}');
+    }
+
+    String trimmedLine = line.trim();
+    if (trimmedLine.isEmpty ||
+        trimmedLine.startsWith('Observatory listening on ')) {
+      return;
+    }
+    logger?.log(fromServer, '$trimmedLine');
+    Map message = asMap(JSON.decoder.convert(trimmedLine));
+    if (message.containsKey('id')) {
+      // The message is a response.
+      Response response = new Response.fromJson(message);
+      _handleResponse(response);
+    } else {
+      // The message is a notification.
+      Notification notification = new Notification.fromJson(message);
+      String event = notification.event;
+      _notificationCountMap[event] = (_notificationCountMap[event] ?? 0) + 1;
+      _handleNotification(notification);
+    }
+  }
+
+  /**
+   * Start listening to output from the server.
+   */
+  void _listenToOutput() {
+    /**
+     * Install the given [handler] to listen to transformed output from the
+     * given [stream].
+     */
+    void installHandler(Stream<List<int>> stream, handler(String line)) {
+      stream
+          .transform((new Utf8Codec()).decoder)
+          .transform(new LineSplitter())
+          .listen(handler);
+    }
+
+    installHandler(_process.stdout, _handleStdOut);
+    installHandler(_process.stderr, _handleStdErr);
+  }
+
+  /**
+   * Send a command to the server. An 'id' will be automatically assigned.
+   */
+  RequestData _send(String method, Map<String, dynamic> params,
+      {void onResponse(Response response)}) {
+    String id = '${_nextId++}';
+    RequestData requestData = new RequestData(id, method, params, currentTime);
+    _requestDataMap[id] = requestData;
+    Map<String, dynamic> command = <String, dynamic>{
+      'id': id,
+      'method': method
+    };
+    if (params != null) {
+      command['params'] = params;
+    }
+    String line = JSON.encode(command);
+    _process.stdin.add(UTF8.encoder.convert('$line\n'));
+    logger?.log(fromClient, '$line');
+    return requestData;
   }
 }
 
@@ -284,6 +1094,6 @@ class _ErrorComparator {
     buffer.writeln(filePath);
     _writeErrors('  Expected ', expectedErrors);
     buffer.writeln();
-    _writeErrors('  Found ', expectedErrors);
+    _writeErrors('  Found ', actualErrors);
   }
 }