Improve help output and Windows VM hack.

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 190 matching lines @@
 class TestOutputImpl implements TestOutput {
   TestCase testCase;
   int exitCode;
   bool timedOut;
   bool failed = false;
   List<String> stdout;
   List<String> stderr;
   Duration time;
   List<String> diagnostics;
 
+  /* A flag to indicate we have already printed a warning about ignoring the VM

[Siggi Cherem (dart-lang), 2012/03/30 01:01:24]

nit: use the style from all other comments
/**
 * A flag ...
 * ...
 */

+   * crash, to limit the amount of output produced per test.
+   */
+  bool alreadyPrintedWarning = false;
+
   /**
    * Set to true if we encounter a condition in the output that indicates we
    * need to rerun this test.
    */
   bool requestRetry = false;
 
   // Don't call  this constructor, call TestOutput.fromCase() to
   // get anew TestOutput instance.
   TestOutputImpl(TestCase this.testCase,
                  int this.exitCode,
@@ skipping 43 matching lines @@
     return (exitCode != 0 && !hasCrashed);
   }
 
   // Reverse result of a negative test.
   bool get hasFailed() {
     // TODO(efortuna): This is a total hack to keep our buildbots (more) green
     // while the VM team solves Issue 2124. Remove when issue is fixed.
     if (new Platform().operatingSystem() == 'windows' && exitCode == 253) {
       for (String line in testCase.output.stdout) {
         if (line.startsWith('VM exited with signal 1073741819')) {
-          print("WARNING: VM crashed on this test with signal 1073741819. " + 
-              "This is a fake pass!!");
-          if (testCase.expectedOutcomes.iterator().hasNext()) {
-            return testCase.expectedOutcomes.iterator().next() == FAIL ? false :
-                true;
+          if (!alreadyPrintedWarning) {
+            print("WARNING: VM crashed on this test with signal 1073741819. " + 
+                "This is a fake pass!!");
+            alreadyPrintedWarning = true;
           }
+          return false;

[Siggi Cherem (dart-lang), 2012/03/30 01:01:24]

should we use: return !testCase.isNegative;

         }
       }
     }
     return (testCase.isNegative ? !didFail : didFail);
   }
 
 }
 
 class BrowserTestOutputImpl extends TestOutputImpl {
   BrowserTestOutputImpl(testCase, exitCode, timedOut, stdout, stderr, time) :
@@ skipping 838 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++;
     }
   }
 }