[PATCH 7/7] t/mwrap: don't dump unless we check the output

[Eric Wong <e@80x24.org>]

No point in putting data into the FS cache that we won't read.
---
 t/mwrap.t | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/t/mwrap.t b/t/mwrap.t
index 3dd3d57..8806847 100644
--- a/t/mwrap.t
+++ b/t/mwrap.t
@@ -18,6 +18,7 @@ my $src = slurp('blib/script/mwrap-perl');
 	mwrap_run('dump test', $env, '-e', '$x = "hello world" x '.$nr);
 	ok(-s $dump, "dump file written to");
 	my $s = slurp($dump);
+	truncate($dump, 0);
 	my $re = qr/([0-9]+)[ \t]+([0-9]+)[ \t]+-e:1[ \t]*\n/sm;
 	my ($bytes, $n);
 	if ($s =~ $re) {
@@ -34,18 +35,13 @@ SKIP: { # C++ program which uses malloc via "new"
 	my $exp = `cmake -h`;
 	skip 'cmake missing', 2 if $?;
 	skip "`cmake -h' gave no output", 2 unless $exp =~ /\S/s;
-	open my $truncate, '>', $dump or die;
-	close $truncate or die;
-	my $env = { MWRAP => "dump_path:$dump" };
-	mwrap_run('cmake (C++ new)', $env, '-e',
-		'system(qw(cmake -h)); exit $?');
+	mwrap_run('cmake (C++ new)', {}, '-e', 'system(qw(cmake -h)); exit $?');
 	my $res = slurp($out);
 	is($res, $exp, "`cmake -h' works");
 };
 
 {
-	my $env = { MWRAP => "dump_path:$dump" };
-	mwrap_run('total_bytes*', $env, '-e', <<'E1');
+	mwrap_run('total_bytes*', {}, '-e', <<'E1');
 my $A = Devel::Mwrap::total_bytes_allocated();
 my $f = Devel::Mwrap::total_bytes_freed();
 print("$A - $f\n");
@@ -55,9 +51,8 @@ E1
 }
 
 {
-	my $env = { MWRAP => "dump_path:$dump" };
-	mwrap_run('source location', $env, 't/source_location.perl');
-	mwrap_run('source location via -d:', $env,
+	mwrap_run('source location', {}, 't/source_location.perl');
+	mwrap_run('source location via -d:', {},
 		'-d:Mwrap', 't/source_location.perl');
 }