Split out a RunnerSuite class.

lib/src/runner/runner_suite.dart

Index: lib/src/runner/runner_suite.dart
diff --git a/lib/src/runner/runner_suite.dart b/lib/src/runner/runner_suite.dart
new file mode 100644
index 0000000000000000000000000000000000000000..589178ff7b3d3ebe6994ae76293e392b6b3a22b6
--- /dev/null
+++ b/lib/src/runner/runner_suite.dart
@@ -0,0 +1,59 @@
+// Copyright (c) 2015, 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 test.runner.runner_suite;
+
+import 'dart:async';
+
+import '../backend/metadata.dart';
+import '../backend/operating_system.dart';
+import '../backend/suite.dart';
+import '../backend/test.dart';
+import '../backend/test_platform.dart';
+import '../util/async_thunk.dart';
+import '../utils.dart';
+
+/// A suite produced and consumed by the test runner that has runner-specific
+/// logic and lifecycle management.
+///
+/// This is separated from [Suite] because the backend library (which will
+/// eventually become its own package) is primarily for test code itself to use,
+/// for which the [RunnerSuite] APIs don't make sense.
+class RunnerSuite extends Suite {
+  /// The thunk for running [close] exactly once.
+  final _closeThunk = new AsyncThunk();
+
+  /// The function to call when the suite is closed.
+  final AsyncFunction _onClose;
+
+  RunnerSuite(Iterable<Test> tests, {String path, TestPlatform platform,
+          OperatingSystem os, Metadata metadata, AsyncFunction onClose})
+      : super(tests,
+          path: path, platform: platform, os: os, metadata: metadata),
+        _onClose = onClose;
+
+  /// Creates a new [RunnerSuite] with the same properties as [suite].
+  RunnerSuite.fromSuite(Suite suite)
+      : super(suite.tests,
+          path: suite.path,
+          platform: suite.platform,
+          os: suite.os,
+          metadata: suite.metadata),
+        _onClose = null;
+
+  RunnerSuite change({String path, Metadata metadata, Iterable<Test> tests}) {
+    if (path == null) path = this.path;
+    if (metadata == null) metadata = this.metadata;
+    if (tests == null) tests = this.tests;
+    return new RunnerSuite(tests, platform: platform, os: os, path: path,
+        metadata: metadata, onClose: this.close);
+  }
+
+  /// Closes the suite and releases any resources associated with it.
+  Future close() {
+    return _closeThunk.run(() async {
+      if (_onClose != null) await _onClose();
+    });
+  }
+}