starting to work on unit test config interface

pkg/unittest/lib/src/simple_configuration.dart

-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// 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.
 
 part of unittest;
 
 // A custom failure handler for [expect] that routes expect failures
 // to the config.
 class _ExpectFailureHandler extends DefaultFailureHandler {
-  Configuration _config;
+  final SimpleConfiguration _config;
 
-  _ExpectFailureHandler(this._config) : super();
+  _ExpectFailureHandler(this._config);
 
   void fail(String reason) {
     _config.onExpectFailure(reason);
   }
 }
 
 /**
  * Hooks to configure the unittest library for different platforms. This class
  * implements the API in a platform-independent way. Tests that want to take
  * advantage of the platform can create a subclass and override methods from
  * this class.
  */
-
-class Configuration {
+class SimpleConfiguration implements Configuration {
   // The VM won't shut down if a receive port is open. Use this to make sure
   // we correctly wait for asynchronous tests.
   ReceivePort _receivePort;
 
   /**
    * Subclasses can override this with something useful for diagnostics.
    * Particularly useful in cases where we have parent/child configurations
    * such as layout tests.
    */
   final String name = 'Configuration';
 
-  /**
-   * If true, then tests are started automatically (otherwise [runTests]
-   * must be called explicitly after the tests are set up.
-   */
-  final bool autoStart = true;
+  bool get autoStart => true;
 
   /**
    * If true (the default), throw an exception at the end if any tests failed.
    */
   bool throwOnTestFailures = true;
 
   /**
    * If true (the default), then tests will stop after the first failed
    * [expect]. If false, failed [expect]s will not cause the test
    * to stop (other exceptions will still terminate the test).
    */
   bool stopTestOnExpectFailure = true;
 
   // If stopTestOnExpectFailure is false, we need to capture failures, which
   // we do with this List.
   final _testLogBuffer = <Pair<String, Trace>>[];
 
   /**
    * The constructor sets up a failure handler for [expect] that redirects
    * [expect] failures to [onExpectFailure].
    */
-  Configuration() {
+  SimpleConfiguration() {
     configureExpectFailureHandler(new _ExpectFailureHandler(this));
   }
-  /**
-   * Called as soon as the unittest framework becomes initialized. This is done
-   * even before tests are added to the test framework. It might be used to
-   * determine/debug errors that occur before the test harness starts executing.
-   * It is also used to tell the vm or browser that tests are going to be run
-   * asynchronously and that the process should wait until they are done.
-   */
+
   void onInit() {
     _receivePort = new ReceivePort();
     _postMessage('unittest-suite-wait-for-done');
   }
 
-  /** Called as soon as the unittest framework starts running. */
   void onStart() {}
 
   /**
    * Called when each test starts. Useful to show intermediate progress on
    * a test suite. Derived classes should call this first before their own
    * override code.
    */
   void onTestStart(TestCase testCase) {
     assert(testCase != null);
     _testLogBuffer.clear();
   }
 
   /**
    * Called when each test is first completed. Useful to show intermediate
-   * progress on a test suite. Derived classes should call this first 
+   * progress on a test suite. Derived classes should call this first
    * before their own override code.
    */
   void onTestResult(TestCase testCase) {
     assert(testCase != null);
     if (!stopTestOnExpectFailure && _testLogBuffer.length > 0) {
       // Write the message/stack pairs up to the last pairs.
       var reason = new StringBuffer();
       for (var reasonAndTrace in
              _testLogBuffer.take(_testLogBuffer.length - 1)) {
         reason.write(reasonAndTrace.first);
         reason.write('\n');
         reason.write(reasonAndTrace.last);
         reason.write('\n');
       }
       var lastReasonAndTrace = _testLogBuffer.last;
       // Write the last message.
       reason.write(lastReasonAndTrace.first);
       if (testCase.result == PASS) {
         testCase._result = FAIL;
         testCase._message = reason.toString();
-        // Use the last stack as the overall failure stack.    
+        // Use the last stack as the overall failure stack.
         testCase._stackTrace = lastReasonAndTrace.last;
       } else {
         // Add the last stack to the message; we have a further stack
         // caused by some other failure.
         reason.write(lastReasonAndTrace.last);
         reason.write('\n');
-        // Add the existing reason to the end of the expect log to 
+        // Add the existing reason to the end of the expect log to
         // create the final message.
         testCase._message = '${reason.toString()}\n${testCase._message}';
       }
     }
   }
 
-  /**
-   * Called when an already completed test changes state; for example a test
-   * that was marked as passing may later be marked as being in error because
-   * it still had callbacks being invoked.
-   */
   void onTestResultChanged(TestCase testCase) {
     assert(testCase != null);
   }
 
   /**
    * Handles the logging of messages by a test case. The default in
    * this base configuration is to call print();
    */
   void onLogMessage(TestCase testCase, String message) {
     print(message);
   }
 
   /**
    * Handles failures from expect(). The default in
    * this base configuration is to throw an exception;
    */
   void onExpectFailure(String reason) {
     if (stopTestOnExpectFailure) {
       throw new TestFailure(reason);
     } else {
       try {
         throw '';
       } catch (_, stack) {
         _testLogBuffer.add(
             new Pair<String, Trace>(reason, new Trace.from(stack)));
       }
     }
   }
-  
+
   /**
    * Format a test result.
    */
   String formatResult(TestCase testCase) {
     var result = new StringBuffer();
     result.write(testCase.result.toUpperCase());
     result.write(": ");
     result.write(testCase.description);
     result.write("\n");
 
@@ skipping 33 matching lines @@
     } else if (failed == 0 && errors == 0 && uncaughtError == null) {
       print('All $passed tests passed.');
     } else {
       if (uncaughtError != null) {
         print('Top-level uncaught error: $uncaughtError');
       }
       print('$passed PASSED, $failed FAILED, $errors ERRORS');
     }
   }
 
-  /**
-   * Called when the unittest framework is done running. [success] indicates
-   * whether all tests passed successfully.
-   */
   void onDone(bool success) {
     if (success) {
       _postMessage('unittest-suite-success');
       _receivePort.close();
     } else {
       _receivePort.close();
       if (throwOnTestFailures) {
         throw new Exception('Some tests failed.');
       }
     }
   }
 
-  /** Handle errors that happen outside the tests. */
-  // TODO(vsm): figure out how to expose the stack trace here
-  // Currently e.message works in dartium, but not in dartc.
-  void handleExternalError(e, String message, [stack]) =>
-      _reportTestError('$message\nCaught $e', stack);
-
-  _postMessage(String message) {
+  void _postMessage(String message) {
     // In dart2js browser tests, the JavaScript-based test controller
     // intercepts calls to print and listens for "secret" messages.
     print(message);
   }
 }