echo(1) is a Unix command line tool, which writes its command line
arguments to the standard output. This is a simple acceptance test
suite for the
For more information, see [@foo2020].
echo without arguments.
when user runs echo without arguments then exit code is 0 then standard output contains a newline then standard error is empty
This scenario runs
echo to produce the output "hello, world".
when user runs echo with arguments hello, world then exit code is 0 then standard output contains "hello, world" then standard error is empty