Merge pull request #1440 from dougwilson/fix/async-stdio

Fix test running output truncation on async STDIO

bin/_mocha

@@ -391,12 +391,32 @@ if (program.watch) {
 // load
 
 mocha.files = files;
-runner = mocha.run(program.exit ? process.exit : exitLater);
+runner = mocha.run(program.exit ? exit : exitLater);
 
 function exitLater(code) {
   process.on('exit', function() { process.exit(code) })
 }
 
+function exit(code) {
+  // flush output for Node.js Windows pipe bug
+  // https://github.com/joyent/node/issues/6247 is just one bug example
+  // https://github.com/visionmedia/mocha/issues/333 has a good discussion
+  function done() {
+    if (!(draining--)) process.exit(code);
+  }
+
+  var draining = 0;
+  var streams = [process.stdout, process.stderr];
+
+  streams.forEach(function(stream){
+    // submit empty write request and wait for completion
+    draining += 1;
+    stream.write('', done);
+  });
+
+  done();
+}
+
 process.on('SIGINT', function() { runner.abort(); })
 
 // enable growl notifications