> From: Philipp Stephani <p.stephani2@gmail.com>
> Date: Wed,  4 Apr 2018 14:02:16 +0200
> Cc: Philipp Stephani <phst@google.com>
>
> * doc/lispref/processes.texi (Asynchronous Processes):
> * src/process.c (Fmake_process): Document that standard error is mixed
> with standard output if STDERR is nil.

Thanks.

> +(ert-deftest make-process/mix-stderr ()
> +  "Check that ‘make-process’ mixes the output streams if STDERR is nil."
> +  (skip-unless (executable-find shell-file-name))
> +  (with-temp-buffer
> +    (let ((process (make-process
> +                    :name "mix-stderr"
> +                    :command (list shell-file-name shell-command-switch
> +                                   "echo stdout; echo stderr >&2")
                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
This shell command is non-portable: on Windows you have to use "&"
instead of ";" to chain commands.  You could use "&&", which in this
case will do the same on both Posix and Windows systems.