read-string from standard-input?

[Michael Albinus]

Hi,

these days, I'm writing some ert tests for shadowfile.el. Unfortunately
some of the functions work strictly interactively, like
shadow-define-cluster. It uses read-string for collecting its arguments.

Running regression tests with interactive input is not what I want. Is
there a technique, that read-string takes its input from a stream, like
standard-input?

TIA, and best regards, Michael.