Run test tearDowns and clean up temporary directories when a signal is caught.

lib/src/utils.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 test.utils;
 
 import 'dart:async';
 
 import 'package:path/path.dart' as p;
 import 'package:stack_trace/stack_trace.dart';
 
 import 'backend/operating_system.dart';
 
 /// A typedef for a possibly-asynchronous function.
 ///
 /// The return type should only ever by [Future] or void.
 typedef AsyncFunction();
 
+/// A typedef for a zero-argument callback function.
+typedef void Callback();
+
 /// A regular expression to match the exception prefix that some exceptions'
 /// [Object.toString] values contain.
 final _exceptionPrefix = new RegExp(r'^([A-Z][a-zA-Z]*)?(Exception|Error): ');
 
 /// Directories that are specific to OS X.
 ///
 /// This is used to try to distinguish OS X and Linux in [currentOSGuess].
 final _macOSDirectories = new Set<String>.from([
   "/Applications",
   "/Library",
@@ skipping 105 matching lines @@
 
   // Otherwise truncate to return the trailing text, but attempt to start at
   // the beginning of a word.
   var result = text.substring(text.length - maxLength + 4);
   var firstSpace = result.indexOf(' ');
   if (firstSpace > 0) {
     result = result.substring(firstSpace);
   }
   return '...$result';
 }
+
+/// Merges [streams] into a single stream that emits events from all sources.
+Stream mergeStreams(Iterable<Stream> streamIter) {
+  var streams = streamIter.toList();
+
+  var subscriptions = new Set();
+  var controller;
+  controller = new StreamController(sync: true, onListen: () {
+    for (var stream in streams) {
+      var subscription;
+      subscription = stream.listen(
+          controller.add,
+          onError: controller.addError,
+          onDone: () {
+        subscriptions.remove(subscription);
+        if (subscriptions.isEmpty) controller.close();
+      });
+      subscriptions.add(subscription);
+    }
+  }, onPause: () {
+    for (var subscription in subscriptions) {
+      subscription.pause();
+    }
+  }, onResume: () {
+    for (var subscription in subscriptions) {
+      subscription.resume();
+    }
+  }, onCancel: () {
+    for (var subscription in subscriptions) {
+      subscription.cancel();
+    }
+  });
+
+  return controller.stream;
+}