Add (failing) source_update_test.dart.

dart/tests/try/test_case.dart

+// Copyright (c) 2014, 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.
+
+library trydart.test_case;
+
+import 'dart:html' show
+    document;
+
+import 'dart:async';
+
+import '../../pkg/async_helper/lib/async_helper.dart';
+
+typedef void VoidFunction();
+
+class TestCase {
+  final String description;
+  final VoidFunction setup;
+  final VoidFunction validate;
+
+  TestCase(this.description, this.setup, this.validate);
+}
+
+/**
+ * Executes [tests] each test in order using the following approach for each
+ * test:
+ *
+ *   1. Run setup synchronously.
+ *
+ *   2. Schedule a new (async) Future which runs validate followed by the next
+ *   test's setup.
+ *
+ *   3. Repeat step 2 until there are no more tests.
+ *
+ * The purpose of this test is to simulate edits (during setup), and then let
+ * the the mutation observer to process the mutations followed by validation.
+ */
+void runTests(List<TestCase> tests) {
+  Completer completer = new Completer();
+  asyncTest(() => completer.future.then((_) {
+    // Clear the DOM to work around a bug in test.dart.
+    document.body.nodes.clear();
+  }));
+
+  void iterateTests(Iterator<TestCase> iterator) {
+    if (iterator.moveNext()) {
+      TestCase test = iterator.current;
+      print('${test.description}\nSetup.');
+      test.setup();
+      new Future(() {
+        test.validate();
+        print('${test.description}\nDone.');
+        iterateTests(iterator);
+      });
+    } else {
+      completer.complete(null);
+    }
+  }
+
+  iterateTests(tests.iterator);
+}