Support Dart 1.8.0.

lib/src/io.dart

 // 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 unittest.io;
 
 import 'dart:async';
 import 'dart:io';
 
+import 'package:path/path.dart' as p;
+
+/// Returns whether the current Dart version supports [Isolate.kill].
+final bool supportsIsolateKill = _supportsIsolateKill;
+bool get _supportsIsolateKill {
+  // This isn't 100% accurate, since early 1.9 dev releases didn't support
+  // Isolate.kill(), but it's very unlikely anyone will be using them.
+  // TODO(nweiz): remove this when we no longer support older Dart versions.
+  var path = p.join(p.dirname(p.dirname(Platform.executable)), 'version');
+  return new File(path).readAsStringSync().startsWith('1.9');
+}
+
 // TODO(nweiz): Make this check [stdioType] once that works within "pub run".
 /// Whether "special" strings such as Unicode characters or color escapes are
 /// safe to use.
 ///
 /// On Windows or when not printing to a terminal, only printable ASCII
 /// characters should be used.
 bool get canUseSpecialChars =>
     Platform.operatingSystem != 'windows' &&
     Platform.environment["_UNITTEST_USE_COLOR"] != "false";
 
@@ skipping 14 matching lines @@
 /// [fn] completes to.
 Future withTempDir(Future fn(String path)) {
   return new Future.sync(() {
     // TODO(nweiz): Empirically test whether sync or async functions perform
     // better here when starting a bunch of isolates.
     var tempDir = Directory.systemTemp.createTempSync('unittest_');
     return new Future.sync(() => fn(tempDir.path))
         .whenComplete(() => tempDir.deleteSync(recursive: true));
   });
 }