antena-spawn/mock/index.js

Uniformely spawn processes with an antena connection

var Events = require("events");
var Stream = require("stream");
var EmitterMock = require("antena/emitter/mock.js");
var Console = require("../util/console.js");
var Terminate = require("../util/terminate.js");

function noop () {}
function pair () {
  var readable = new Stream.Readable({
    read: noop,
    destroy: function (error, callback) { writable.destroy(error, callback) }
  });
  var writable = new Stream.Writable({
    decodeStrings: false,
    destroy: function (error, callback) { readable.destroy(error, callback) },
    write: function (chunk, encoding, callback) {
      readable.push(chunk, encoding);
      callback();
    }
  });
  return {readable:readable, writable:writable};
}

module.exports = function (receptor) {
  return function (script, argv) {
    var child = new Events();
    var mock = new Events();
    (function (stdin) {
      child.stdin = stdin.writable;
      mock.stdin = stdin.readable;
    } (pair()));
    (function (stdout) {
      child.stdout = stdout.readable;
      mock.stdout = stdout.writable;
    } (pair()));
    (function (stderr) {
      child.stderr = stderr.readable;
      mock.stderr = stderr.writable;
    } (pair()));
    child.send = function (message) { mock.emit("message", JSON.parse(JSON.stringify(message))) };
    mock.send = function (message) { child.emit("message", JSON.parse(JSON.stringify(message))) };
    child.kill = function (signal) { Terminate(child, null, signal) };
    mock.exit = function (code) { Terminate(child, code, null) };
    child.stdio = [child.stdin, child.stdout, child.stderr];
    mock.emitter = EmitterMock(receptor);
    mock.argv = ["mock", "inline"].concat(argv || []);
    setTimeout(function () {
      var main = Function("global", "process", "console", script);
      try {
        main(global, mock, Console(mock.stdout, mock.stderr));
      } catch (error) {
        mock.stderr.write(error && "stack" in error ? error.stack : ""+error+"\n");
      }
    }, 0);
    return child;
  };
};