def METHOD_NAME(self):
    out_file = os.path.join(self.obj.engine.artifacts_dir, 'out.txt')
    err_file = os.path.join(self.obj.engine.artifacts_dir, 'err.txt')
    file1 = self.obj.engine.create_artifact('file_1.out', "")
    file2 = self.obj.engine.create_artifact('file_2.out', "")
    command = "echo 1 > {file1} && sleep 1 && echo 2 > {file2}"
    task = {"command": command.format(file1=file1, file2=file2), "out": out_file, "err": err_file}
    self.obj.parameters.merge({"prepare": [task]})
    self.obj.prepare()
    self.assertEqual(open(file1).read().strip(), '1')
    self.assertEqual(open(file2).read().strip(), '2')
    self.assertTrue(os.path.exists(out_file))
    self.assertTrue(os.path.exists(os.path.join(self.obj.engine.artifacts_dir, err_file)))