Re: Need help adding a test in commands.exp

[Daniel Jacobowitz <drow at mvista dot com>]

On Sat, Jul 27, 2002 at 11:26:21PM -0700, Joel Brobecker wrote:
> I found a bug in GDB, and I have fixed this bug without causing new
> regressions. But I want to add a new test in the commands.exp testcase.
> Here is the output I get from GDB when I run the test manually:
> 
>         (gdb) b factorial
>         Breakpoint 1 at 0x8048506: file ./gdb.base/run.c, line 77.
>         (gdb) commands
>         Type commands for when breakpoint 1 is hit, one per line.
>         End with a line saying just "end".
>         >silent
>         >printf "factorial command-list executed\n"
>         >clear factorial
>         >cont
>         >end
>         (gdb) run 1
>         Starting program: [...]/gdb.base/run 1
>         factorial command-list executed
>         1
>         
>         Program exited normally.
>         (gdb)       
> 
> I am attaching a patch to commands.exp. When I run the test using
> "runtest gdb.base/commands.exp", I get all passes except the last one:
> 
>         PASS: breakpoint in bp_deleted_in_command_test
>         PASS: begin commands in bp_deleted_in_command_test
>         PASS: add silent command
>         PASS: add printf command
>         PASS: add clear command
>         PASS: add cont command
>         PASS: end commands
>         FAIL: run factorial until breakpoint (no output)
>         
> I don't undestand why I don't get any output from the "run 1" command
> that I sent to GDB. I tried running runtest with "-v", but did not find
> any useful information there. It must be something pretty silly, but
> I am not very familiar with dejagnu nor tcl.
> 
> Any idea?

Welcome to the wonderful world of expect.

I recommend using "exp_internal 1" right before the problematic test;
this will tell you what sort of matching expect is doing. 
"exp_internal 0" can turn it off again.

The particular problem here is:

> +     send_gdb "run 1\n"
> +     gdb_expect {
> +         -re ".*factorial command-list executed.*1.*Program exited normally.*" {
> +             pass "run factorial until breakpoint"
> +         }
> +         -re "" { fail "run factorial until breakpoint (no output)" }
> +         timeout { fail "(timeout) run factorial until breakpoint" }
> +     }

"" matches immediately, before the output has been produced.  You
should explicitly match $gdb_prompt (which requires declaring it
global).

There's some other problems here; you can't just send a "run" in the
testsuite, and you can't require that the program accept arguments.
Look for gdb_continue (I think) and a flag in the board description
which describes whether argument passing works.

-- 
Daniel Jacobowitz                           Carnegie Mellon University
MontaVista Software                         Debian GNU/Linux Developer