Fix issue 6389; Asynchronous test failures cause cascading bugs in asynchronous tests.

pkg/unittest/unittest.dart

 // Copyright (c) 2011, 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 library for writing dart unit tests.
  *
  * To import this library, use the pub package manager.
  * Create a pubspec.yaml file in your project and add
  * a dependency on unittest with the following lines:
@@ skipping 359 matching lines @@
   _SpreadArgsHelper.variableCallCount(callback, isDone) {
     _init(callback, _always, isDone, 1);
    }
 
   _SpreadArgsHelper.optionalCalls(callback) {
     _init(callback, _always, () => false, 0);
    }
 
   _after() {
     if (_isDone()) {
-      _handleCallbackFunctionComplete();
+      _handleCallbackFunctionComplete(_testNum);
     }
   }
 
   _allCallsDone() => _actualCalls == _expectedCalls;
 
   _always() {
     // Always run except if the test is done.
     if (_testCase.isComplete) {
       _testCase.error(
           'Callback called after already being marked as done ($_actualCalls).',
@@ skipping 248 matching lines @@
  * calls to [test].
  */
 void tearDown(Function teardownTest) {
   _testTeardown = teardownTest;
 }
 
 /**
  * Called when one of the callback functions is done with all expected
  * calls.
  */
-void _handleCallbackFunctionComplete() {
+void _handleCallbackFunctionComplete(testNum) {
   // TODO (gram): we defer this to give the nextBatch recursive
   // stack a chance to unwind. This is a temporary hack but
   // really a bunch of code here needs to be fixed. We have a
   // single array that is being iterated through by nextBatch(),
   // which is recursively invoked in the case of async tests that
   // run synchronously. Bad things can then happen.
   _defer(() {
+    if (_currentTest != testNum) {
+      if (_tests[testNum].result == PASS) {
+        _tests[testNum].error("Unexpected extra callbacks");
+      }
+      return; // Extraneous callback.
+    }
     if (_currentTest < _tests.length) {
       final testCase = _tests[_currentTest];
       --testCase.callbackFunctionsOutstanding;
       if (testCase.callbackFunctionsOutstanding < 0) {
         // TODO(gram): Check: Can this even happen?
         testCase.error(
             'More calls to _handleCallbackFunctionComplete() than expected.',
              '');
       } else if (testCase.callbackFunctionsOutstanding == 0) {
         if (!testCase.isComplete) {
           testCase.pass();
         }
         _nextTestCase();
       }
     }
   });
 }
 
 /** Advance to the next test case. */
 void _nextTestCase() {
   _currentTest++;
   _testRunner();
 }
 
 /**
  * Temporary hack: expose old API.
  * TODO(gram) remove this when WebKit tests are working with new framework
  */
 void callbackDone() {
-  _handleCallbackFunctionComplete();
+  _handleCallbackFunctionComplete(_currentTest);
 }
 
 /**
  * Utility function that can be used to notify the test framework that an
  *  error was caught outside of this library.
  */
 void _reportTestError(String msg, String trace) {
  if (_currentTest < _tests.length) {
     final testCase = _tests[_currentTest];
     testCase.error(msg, trace);
@@ skipping 200 matching lines @@
 }
 
 /** Enable a test by ID. */
 void enableTest(int testId) => _setTestEnabledState(testId, true);
 
 /** Disable a test by ID. */
 void disableTest(int testId) => _setTestEnabledState(testId, false);
 
 /** Signature for a test function. */
 typedef void TestFunction();