Unit test improvements.

pkg/unittest/lib/src/config.dart

Index: pkg/unittest/lib/src/config.dart
===================================================================
--- pkg/unittest/lib/src/config.dart	(revision 22128)
+++ pkg/unittest/lib/src/config.dart	(working copy)
@@ -4,6 +4,18 @@
 
 part of unittest;
 
+// A custom failure handler for [expect] that routes expect failures
+// to the config.
+class _ExpectFailureHandler extends DefaultFailureHandler {
+  Configuration _config;
+
+  _ExpectFailureHandler(this._config) : super();
+
+  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
@@ -30,6 +42,29 @@
   final bool 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.
+  List _testLogBuffer = new List();
+  
+  /**
+   * The constructor sets up a failure handler for [expect] that redirects
+   * [expect] failures to [onExpectFailure].
+   */
+  Configuration() {
+    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.
@@ -46,18 +81,48 @@
 
   /**
    * Called when each test starts. Useful to show intermediate progress on
-   * a test suite.
+   * 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.
+   * 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 i = 0; i < _testLogBuffer.length - 2; i += 2) {
+        reason.write(_testLogBuffer[i]);
+        reason.write('\n');
+        reason.write(_formatStack(_testLogBuffer[i+1]));
+        reason.write('\n');
+      }
+      // Write the last message.
+      reason.write(_testLogBuffer[_testLogBuffer.length - 2]);
+      if (testCase.result == PASS) {
+        testCase._result = FAIL;
+        testCase._message = reason.toString();
+        // Use the last stack as the overall failure stack.    
+        testCase._stackTrace = 
+            _formatStack(_testLogBuffer[_testLogBuffer.length - 1]);
+      } else {
+        // Add the last stack to the message; we have a further stack
+        // caused by some other failure.
+        reason.write(_formatStack(_testLogBuffer[_testLogBuffer.length - 1]));
+        reason.write('\n');
+        // Add the existing reason to the end of the expect log to 
+        // create the final message.
+        testCase._message = '${reason.toString()}\n${testCase._message}';
+      }
+    }
   }
 
   /**
@@ -78,6 +143,23 @@
   }
 
   /**
+   * 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 {
+      _testLogBuffer.add(reason);
+      try {
+        throw '';
+      } catch (_, stack) {
+        _testLogBuffer.add(stack);
+      }
+    }
+  }
+  
+  /**
    * Called with the result of all test cases. The default implementation prints
    * the result summary using the built-in [print] command. Browser tests
    * commonly override this to reformat the output.
@@ -127,7 +209,9 @@
       _receivePort.close();
     } else {
       _receivePort.close();
-      throw new Exception('Some tests failed.');
+      if (throwOnTestFailures) {
+        throw new Exception('Some tests failed.');
+      }
     }
   }