--- a/debug_connection.t
+++ b/debug_connection.t
@@ -56,27 +56,14 @@ EOF
 
 ###############################################################################
 
-my $d = $t->testdir();
-
 http_get('/');
-is(read_file("$d/debug1.log"), '', 'no debug_connection file 1');
-is(read_file("$d/debug2.log"), '', 'no debug_connection file 1');
+is($t->read_file('debug1.log'), '', 'no debug_connection file 1');
+is($t->read_file('debug2.log'), '', 'no debug_connection file 1');
 
 http_get('/debug');
-like(read_file("$d/debug1.log"), qr/\[debug\]/, 'debug_connection file 1');
-like(read_file("$d/debug2.log"), qr/\[debug\]/, 'debug_connection file 2');
-is(read_file("$d/debug1.log"), read_file("$d/debug2.log"),
+like($t->read_file('debug1.log'), qr/\[debug\]/, 'debug_connection file 1');
+like($t->read_file('debug2.log'), qr/\[debug\]/, 'debug_connection file 2');
+is($t->read_file('debug1.log'), $t->read_file('debug2.log'),
 	'debug_connection file1 file2 match');
 
 ###############################################################################
-
-sub read_file {
-	my ($file) = shift;
-	open my $fh, '<', $file or return "$!";
-	local $/;
-	my $content = <$fh>;
-	close $fh;
-	return $content;
-}
-
-###############################################################################