Add a dedicated Result for skipped tests.

lib/src/backend/invoker.dart

 // Copyright (c) 2015, 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.
 
 import 'dart:async';
 
 import 'package:stack_trace/stack_trace.dart';
 
 import '../backend/group.dart';
 import '../frontend/expect.dart';
@@ skipping 216 matching lines @@
             new TimeoutException(
                 "Test timed out after ${niceDuration(timeout)}.", timeout));
       });
     });
   }
 
   /// Notifies the invoker of an asynchronous error.
   void _handleError(error, [StackTrace stackTrace]) {
     if (stackTrace == null) stackTrace = new Chain.current();
 
-    var afterSuccess = liveTest.isComplete &&
-        liveTest.state.result == Result.success;
+    // Store this here because it'll change when we set the state below.
+    var shouldBeDone = liveTest.state.shouldBeDone;
 
     if (error is! TestFailure) {
       _controller.setState(const State(Status.complete, Result.error));
     } else if (liveTest.state.result != Result.error) {
       _controller.setState(const State(Status.complete, Result.failure));
     }
 
     _controller.addError(error, stackTrace);
     removeAllOutstandingCallbacks();
 
-    // If a test was marked as success but then had an error, that indicates
+    // If a test was supposed to be done but then had an error, that indicates
     // that it was poorly-written and could be flaky.
-    if (!afterSuccess) return;
+    if (!shouldBeDone) return;
 
     // However, users don't think of load tests as "tests", so the error isn't
     // helpful for them.
     //
     // TODO(nweiz): Find a way of avoiding this error that doesn't require
     // Invoker to refer to a class from the runner.
     if (liveTest.suite is LoadSuite) return;
 
     _handleError(
         "This test failed after it had already completed. Make sure to use "
@@ skipping 38 matching lines @@
         // outstanding callback counters at once.
         _counterKey: outstandingCallbacksForBody,
         _closableKey: true
       },
           zoneSpecification: new ZoneSpecification(
               print: (self, parent, zone, line) => _controller.print(line)),
           onError: _handleError);
     });
   }
 }