Fix bug in the unittest's withTestEnvironment package and apply more feedback from nweiz.

pkg/unittest/lib/src/test_environment.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.
 
 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.
   ///
-  /// == -1 implies the test system is not running.
-  /// == [number of test cases] is a short-lived state flagging that the last
-  ///    test has completed.
+  /// 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;
   }
 }