use strict;
use warnings;

use Inline C => <<'EOC';

SV * foo( SV * in ) {
   /*  printf("# %s\n", SvPV_nolen(in)); */
   return newSVpv(SvPV_nolen(in), 0);
}

EOC

my $ok = 1;

print "1..1\n";

for(1 .. 1000) {
  my $n = int(rand(10000000));
  $ok = 0 if foo("$n") ne "$n";
}

if($ok) { print "ok 1\n" }
else {
  print "not ok 1\n";
}

__END__
[download]

$ perl -MTAP::Harness -e '$h = TAP::Harness->new(); $h->runtests("./tr
+y.pl");'
./try.pl .. ok
All tests successful.
Files=1, Tests=1,  0 wallclock secs ( 0.04 usr  0.01 sys +  0.06 cusr 
+ 0.01 csys =  0.12 CPU)
Result: PASS
[download]

 $ perl -MTAP::Harness -e '$h = TAP::Harness->new(); $h->runtests("./t
+ry.pl");'
./try.pl .. All 1 subtests passed

Test Summary Report
-------------------
./try.pl (Wstat: 0 Tests: 1 Failed: 0)
  Parse errors: No plan found in TAP output
Files=1, Tests=1,  1 wallclock secs ( 0.11 usr  0.01 sys +  0.05 cusr 
+ 0.02 csys =  0.19 CPU)
Result: FAIL
[download]

Thanks for this example. I have run your code with the printf uncommented and reproduced your findings (on Linux) but only on some runs. The result is inconsistent. Here is the output from 2 runs within a few seconds of each other:

10045 $ perl -MTAP::Harness -e '$h = TAP::Harness->new(); $h->runtests
+("./11138492.pl");'
./11138492.pl .. ok   
All tests successful.
Files=1, Tests=1,  0 wallclock secs ( 0.06 usr  0.00 sys +  0.04 cusr 
+ 0.00 csys =  0.10 CPU)
Result: PASS
10046 $ perl -MTAP::Harness -e '$h = TAP::Harness->new(); $h->runtests
+("./11138492.pl");'
./11138492.pl .. All 1 subtests passed 

Test Summary Report
-------------------
./11138492.pl (Wstat: 0 Tests: 1 Failed: 0)
  Parse errors: No plan found in TAP output
Files=1, Tests=1,  0 wallclock secs ( 0.06 usr  0.01 sys +  0.04 cusr 
+ 0.00 csys =  0.11 CPU)
Result: FAIL
[download]

However, upon inspection the problem is not with TAP::Harness. The output of just running the script shows that the plan can appear in the middle of your data. Again, running a few times gives:

10046 $ perl 11138492.pl | grep -Fn 1..1
830:# 79678951..1
10047 $ perl 11138492.pl | grep -Fn 1..1
830:# 691..1
10047 $ perl 11138492.pl | grep -Fn 1..1
829:# 5056771..1
[download]

So this looks to be a buffering issue. If I simply modify your code to include $|++; before the plan is printed then the script runs fine, the plan is printed at the top and the test harness has no complaints.

Not a bug in Test::Harness after all.

---

🦛

Not a bug in Test::Harness after all.

Cool ... creating bug reports always ends up in being more work than one anticipates.
Thank you !!

If I simply modify your code to include $|++; before the plan is printed then the script runs fine

I thought that print "1..1\n" should flush the buffer immediately (because of the "\n") without any need to increment $|.
And this notion is supported by the following one-liner that prints out a "." followed by a newline every second for 10 seconds:

$ perl -e 'for(1..10) {print ".\n"; sleep 1}'
[download]

whereas this next one-liner (as expected) prints nothing for 10 seconds, and then immediately prints out all 10 dots:

$ perl -e 'for(1..10) {print "."; sleep 1}'
[download]

I don't doubt that I'm missing something pretty basic ... and I shudder to think what the answer might be .... but I'll ask the question "what is it that I'm missing ?", anyway ;-)

Cheers,
Rob

Plan has to go first. This is TAP. http://testanything.org/tap-specification.html

Plan has to go first

Sorry - I'm not clever enough to grasp your point.
AFAICS, the "Plan" is in exactly the same location, irrespective of whether the printf() statement is included or not.

Cheers,
Rob