Re: tr/pty-all (Re: What's cooking in git.git (Dec 2011, #04; Tue, 13))

[Jeff King <peff@peff.net>]

On Wed, Dec 14, 2011 at 05:31:19PM -0600, Jonathan Nieder wrote:

> > @@ -469,7 +471,7 @@ test_debug () {
> >  test_eval_ () {
> >  	# This is a separate function because some tests use
> >  	# "return" to end a test_expect_success block early.
> > -	eval >&3 2>&4 "$*"
> > +	eval <"$TEST_DIRECTORY/stdin-garbage" >&3 2>&4 "$*"
> 
> How about /dev/urandom on platforms that support it?  It wouldn't be
> as pleasant to debug as "This is a magic stdin garbage stream", but it
> would be more likely to (despite the name :)) predictably trip errors,
> or at least hangs, in problematic tests.

I'd rather have something deterministic. If you really want to be mean
to accidental readers of stdin, then put binary junk into stdin-garbage
(even the results of a single run of /dev/urandom, if you like). But I
suspect arbitrary text is good enough to throw a monkey wrench into
anything that will care about its input (and those that don't are beyond
our ability to auto-detect anyway[1]). And it's way easier to debug than
seeing random binary bits.

-Peff

[1] Actually, you could abandon the idea of feeding garbage altogether,
and instead open the descriptor outside the test, then check that its
offset is still 0 after the test. You'd have to use a helper program to
do the ftell(), but it should work as the descriptor position will be
shared.