Allow asynchronous tests to explicitly register exceptions along with stack traces.

lib/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, specify the relative path to
  * lib/unittest/unittest.dart.
  *
@@ skipping 651 matching lines @@
   });
 }
 
 /**
  * Run [tryBody] guarded in a try-catch block. If an exception is thrown, update
  * the [_currentTest] status accordingly.
  */
 guardAsync(tryBody, [finallyBody]) {
   try {
     return tryBody();
-  } catch (ExpectException e, var trace) {
+  } catch (var e, var trace) {
+    registerException(e, trace);
+  } finally {
+    _state = _READY;
+    if (finallyBody != null) finallyBody();
+  }
+}
+
+/**
+ * Registers that an exception was caught for the current test.
+ */
+registerException(e, [trace]) {
+  if (e is ExpectException) {
     Expect.isTrue(_currentTest < _tests.length);
     if (_state != _UNCAUGHT_ERROR) {
       _tests[_currentTest].fail(e.message,
           trace == null ? '' : trace.toString());
     }
-  } catch (var e, var trace) {
+  } else {
     if (_state == _RUNNING_TEST) {
       // If a random exception is thrown from within a test, we consider that
       // a test failure too. A test case implicitly has an expectation that it
       // will run to completion without an uncaught exception being thrown.
       _tests[_currentTest].fail('Caught $e',
           trace == null ? '' : trace.toString());
     } else if (_state != _UNCAUGHT_ERROR) {
       _tests[_currentTest].error('Caught $e',
           trace == null ? '' : trace.toString());
     }
-  } finally {
-    _state = _READY;
-    if (finallyBody != null) finallyBody();
   }
 }
 
 /**
  * Runs a batch of tests, yielding whenever an asynchronous test starts
  * running. Tests will resume executing when such asynchronous test calls
  * [done] or if it fails with an exception.
  */
 _nextBatch() {
   while (_currentTest < _tests.length) {
@@ skipping 66 matching lines @@
   _config.onInit();
 
   // Immediately queue the suite up. It will run after a timeout (i.e. after
   // main() has returned).
   _defer(_runTests);
 }
 
 /** Signature for a test function. */
 typedef void TestFunction();