Split unittest tests into separate test files.

pkg/unittest/test/unittest_late_exception_test.dart

+// 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.
+
+library unittestTest;
+import 'dart:isolate';
+import 'dart:async';
+import 'package:unittest/unittest.dart';
+
+part 'unittest_test_utils.dart';
+
+var testName = 'late exception test';
+
+var testFunction = (_) {
+  var f;
+  test('testOne', () {
+    f = expectAsync0(() {});
+    _defer(f);
+  });
+  test('testTwo', () {
+    _defer(expectAsync0(() { f(); }));
+  });
+};
+
+var expected = buildStatusString(1, 0, 1, 'testOne',
+    message: 'Callback called (2) after test case testOne has already '
+        'been marked as pass.:testTwo:');