use strict; use File::Temp qw( tempfile ); BEGIN { if($ENV{INTERNAL_DEBUG}) { require Log::Log4perl::InternalDebug; Log::Log4perl::InternalDebug->enable(); } } my($tmpfh, $tempfile) = tempfile( UNLINK => 1 ); use Test::More; BEGIN { plan tests => 1 }; use Log::Log4perl qw( :easy ); Log::Log4perl->easy_init( { level => $DEBUG, file => $tempfile } ); my $warnings = ""; $SIG{__WARN__} = sub { $warnings .= $_[0]; }; DEBUG "foo", undef, "bar"; like $warnings, qr/Log message argument #2/, "warning for undef element issued";