Add handler for Process.onError in test_runner.dart.

tools/testing/dart/test_runner.dart

 // Copyright (c) 2012, 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.
 
 /**
  * Classes and methods for executing tests.
  *
  * This module includes:
  * - Managing parallel execution of tests, including timeout checks.
  * - Evaluating the output of each test as pass/fail/crash/timeout.
@@ skipping 171 matching lines @@
 
   String get result();
 
   bool get unexpectedOutput();
 
   bool get hasCrashed();
 
   bool get hasTimedOut();
 
   bool get didFail();
-  
+
   bool requestRetry;
 
   Duration get time();
 
   int get exitCode();
 
   List<String> get stdout();
 
   List<String> get stderr();
 
@@ skipping 390 matching lines @@
   void runCommand(Command command,
                   void exitHandler(int exitCode)) {
     if (Platform.operatingSystem() == 'windows') {
       // Windows can't handle the first command if it is a .bat file or the like
       // with the slashes going the other direction.
       // TODO(efortuna): Remove this when fixed (Issue 1306).
       command.executable = command.executable.replaceAll('/', '\\');
     }
     process = new Process.start(command.executable, command.arguments);
     process.onExit = exitHandler;
+    process.onError = (e) {
+      print("Error starting process:");
+      print("  Command: $command");
+      print("  Error: $e");
+    };
     startTime = new Date.now();
     InputStream stdoutStream = process.stdout;
     InputStream stderrStream = process.stderr;
     StringInputStream stdoutStringStream = new StringInputStream(stdoutStream);
     StringInputStream stderrStringStream = new StringInputStream(stderrStream);
     stdoutStringStream.onLine =
         makeReadHandler(stdoutStringStream, stdout);
     stderrStringStream.onLine =
         makeReadHandler(stderrStringStream, stderr);
     if (timeoutTimer == null) {
@@ skipping 187 matching lines @@
     _process = new Process.start(_executable, _batchArguments);
     _stdoutStream = new StringInputStream(_process.stdout);
     _stderrStream = new StringInputStream(_process.stderr);
     _testStdout = new List<String>();
     _testStderr = new List<String>();
     _stdoutDrained = false;
     _stderrDrained = false;
     _stdoutStream.onLine = _readStdout(_stdoutStream, _testStdout);
     _stderrStream.onLine = _readStderr(_stderrStream, _testStderr);
     _process.onExit = _exitHandler;
+    _process.onError = (e) {
+      print("Error starting process:");
+      print("  Command: $_executable ${Strings.join(_batchArguments, ' ')}");
+      print("  Error: $e");
+    };
     _process.onStart = then;
   }
 }
 
 /**
  * ProcessQueue is the master control class, responsible for running all
  * the tests in all the TestSuites that have been registered.  It includes
  * a rate-limited queue to run a limited number of tests in parallel,
  * a ProgressIndicator which prints output when tests are started and
  * and completed, and a summary report when all tests are completed,
@@ skipping 159 matching lines @@
       // Check to see if the jar was already running before the program started.
       String cmd = 'ps';
       var arg = ['aux'];
       if (Platform.operatingSystem() == 'windows') {
         cmd = 'tasklist';
         arg.add('/v');
       }
       Process p = new Process.start(cmd, arg);
       final StringInputStream stdoutStringStream =
           new StringInputStream(p.stdout);
+      p.onError = (e) {
+        print("Error starting process:");
+        print("  Command: $cmd ${Strings.join(arg, ' ')}");
+        print("  Error: $e");
+      };
       stdoutStringStream.onLine = () {
         var line = stdoutStringStream.readLine();
         while (null != line) {
           if (const RegExp(@".*selenium-server-standalone.*").hasMatch(line)) {
             _seleniumAlreadyRunning = true;
             resumeTesting();
           }
           line = stdoutStringStream.readLine();
         }
         if (!_isSeleniumAvailable) {
@@ skipping 41 matching lines @@
     // Get the absolute path to the Selenium jar.
     String filePath = new Options().script;
     String pathSep = Platform.pathSeparator();
     int index = filePath.lastIndexOf(pathSep);
     filePath = filePath.substring(0, index) + '${pathSep}testing${pathSep}';
     var dir = new Directory(filePath);
     dir.onFile = (String file) {
       if (const RegExp(@"selenium-server-standalone-.*\.jar").hasMatch(file)
           && _seleniumServer == null) {
         _seleniumServer = new Process.start('java', ['-jar', file]);
+        _seleniumServer.onError = (e) {
+          print("Error starting process:");
+          print("  Command: java -jar $file");
+          print("  Error: $e");
+        };
         // Heads up: there seems to an obscure data race of some form in
         // the VM between launching the server process and launching the test
         // tasks that disappears when you read IO (which is convenient, since
         // that is our condition for knowing that the server is ready).
         StringInputStream stdoutStringStream =
             new StringInputStream(_seleniumServer.stdout);
         StringInputStream stderrStringStream =
             new StringInputStream(_seleniumServer.stderr);
         stdoutStringStream.onLine =
             makeSeleniumServerHandler(stdoutStringStream);
@@ skipping 76 matching lines @@
         // the developer doesn't waste his or her time trying to fix a bunch of
         // tests that appear to be broken but were actually just flakes that
         // didn't get retried because there had already been one failure.
         bool allowRetry = _MAX_FAILED_NO_RETRY > _progress.numFailedTests;
         new RunningProcess(test, allowRetry, this).start();
       }
       _numProcesses++;
     }
   }
 }