Add observatory_pub_packages snapshot to third_party

observatory_pub_packages/unittest/src/test_environment.dart

Index: observatory_pub_packages/unittest/src/test_environment.dart
===================================================================
--- observatory_pub_packages/unittest/src/test_environment.dart	(revision 0)
+++ observatory_pub_packages/unittest/src/test_environment.dart	(working copy)
@@ -0,0 +1,54 @@
+// 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.
+
+part of unittest;
+
+/// Class for encapsulating test environment state.
+///
+/// This is used by the [withTestEnvironment] method to support multiple
+/// invocations of the unittest library within the same application
+/// instance.
+class _TestEnvironment {
+  Configuration config;
+
+  // We use a 'dummy' context for the top level to eliminate null
+  // checks when querying the context. This allows us to easily
+  //  support top-level [setUp]/[tearDown] functions as well.
+  final rootContext = new _GroupContext();
+  _GroupContext currentContext;
+
+  /// The [currentTestCaseIndex] represents the index of the currently running
+  /// test case.
+  ///
+  /// If this is -1 it implies the test system is not running.
+  /// It will be set to [number of test cases] as a short-lived state flagging
+  /// that the last test has completed.
+  int currentTestCaseIndex = -1;
+
+  /// The [initialized] variable specifies whether the framework
+  /// has been initialized.
+  bool initialized = false;
+
+  /// The time since we last gave asynchronous code a chance to be scheduled.
+  int lastBreath = new DateTime.now().millisecondsSinceEpoch;
+
+  /// The set of tests to run can be restricted by using [solo_test] and
+  /// [solo_group].
+  ///
+  /// As groups can be nested we use a counter to keep track of the nesting
+  /// level of soloing, and a flag to tell if we have seen any solo tests.
+  int soloNestingLevel = 0;
+  bool soloTestSeen = false;
+
+  /// The list of test cases to run.
+  final List<TestCase> testCases = new List<TestCase>();
+
+  /// The [uncaughtErrorMessage] holds the error messages that are printed
+  /// in the test summary.
+  String uncaughtErrorMessage;
+
+  _TestEnvironment() {
+    currentContext = rootContext;
+  }
+}