Refactoring to allow html_individual_config to pass with zero tests executed.

pkg/unittest/lib/html_individual_config.dart

 // Copyright (c) 2013, 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.
 
 /**
  * A unit test library for running groups of tests in a browser, instead of the
  * entire test file. This is especially used for large tests files that have
  * many subtests, so we can mark groups as failing at a finer granularity than
  * the entire test file.
  *
@@ skipping 23 matching lines @@
         }
 
         var testGroupName = groups.single.split('=')[1];
         var startsWith = "$testGroupName${unittest.groupSep}";
         unittest.filterTests((unittest.TestCase tc) =>
             tc.description.startsWith(startsWith));
       }
     }
     super.onStart();
   }
+
+  bool _failedOrErrors = false;
+  void onSummary(int passed, int failed, int errors, List<TestCase> results,
+      String uncaughtError) {
+    super.onSummary(passed, failed, errors, results, uncaughtError);
+
+    _failedOrErrors = failed > 0 || errors > 0;
+  }
+
+  void onDone(bool success) {
+    if (!success) {
+      success = !_failedOrErrors;
+    }
+    super.onDone(success);
+  }
 }
 
 void useHtmlIndividualConfiguration([bool isLayoutTest = false]) {
   unittest.unittestConfiguration = isLayoutTest ? _singletonLayout : _singletonNotLayout;
 }
 
 final _singletonLayout = new HtmlIndividualConfiguration(true);
 final _singletonNotLayout = new HtmlIndividualConfiguration(false);