how to test for input in interactive tests?

[Benjamin Kosnik]

I'm hoping somebody on this list can figure out how to do the last
remaining bit on the 27_io testsuite. I've been beaten.

Here's the deal: some of the io tests require input. These tests, now
clearly identified with the _xin.cc suffix, have a corresponding _xin.in
file that contains input. All of these tests are set up so that 

echo foo_xin.in | foo_xin.exe 

would work, if I could figure out how to automate it. There is even a
separate list of the interactive tests (testsuite_files_interactive).
The thought was to make some magic, and then in the main dejagnu loop do:

dg-runtest [v3-list-tests testsuite_files] "" $DEFAULT_CXXFLAGS
#dg-runtest [v3-list-tests testsuite_files_interactive] "" $DEFAULT_CXXFLAGS
 
Of course, this has to be done in tcl/expect/dejagnu, which I find as much
fun as smoking cigarettes while dosed in gasoline.

I didn't see any prior art in the glibc/libjava testsuites.

-benjamin