capture the warning in the test using Test::Warn

Changes

@@ -2,6 +2,7 @@ Revision history for Perl extension Syntax::Highlight::Engine::Kate.
 
 
 0.09 
+    - Require Test::Warn for testing.
     - Support case insensitive names. RT #84982 (Jeff Fearn)
     - Replace use of File::Slurp with Path::Tiny (Martin McGrath)
     - Spelling RT #88156 (Debian)

Makefile.PL

@@ -12,7 +12,8 @@ requires       'Path::Tiny'               => '0';
 requires       'Data::Dumper'             => '0';
 requires       'File::Basename'           => '0';
 
-test_requires  'Test::More'               => '0.88';
+test_requires  'Test::More'               => '1.00';
+test_requires  'Test::Warn'               => '0.30';
 test_requires  'Test::Differences'        => '0.61';
 test_requires  'Term::ANSIColor'          => '0';
 

lib/Syntax/Highlight/Engine/Kate.pm

@@ -9,7 +9,7 @@ use 5.006;
 our $VERSION = '0.08';
 use strict;
 use warnings;
-use Carp;
+use Carp qw(carp);
 use Data::Dumper;
 use File::Basename;
 
@@ -623,19 +623,19 @@ sub languagePlug {
 			my $matched = 0;
 			foreach my $key (keys(%{$self->{'syntaxes'}})) {
 				if (lc($key) eq lc($req)) {
-					warn "substituting language $key for $req";
+					carp "substituting language $key for $req";
 					$req = $key;
 					$matched = 1;
 					last;
 				}
 			}
 
 			unless ($matched) {
-				warn "undefined language: $req";
+				carp "undefined language: $req";
 				return undef;
 			}
 		} else {
-			warn "undefined language: $req";
+			carp "undefined language: $req";
 			return undef;
 		}
 	}

t/10-case.t

@@ -2,12 +2,26 @@ use strict;
 use warnings;
 
 use Test::More tests => 4;
+use Test::Warn;
 use Syntax::Highlight::Engine::Kate;
 
 my $hl = new Syntax::Highlight::Engine::Kate();
 
 is($hl->languagePlug( 'HTML'), 'HTML', 'Standard "HTML" should work');
-is($hl->languagePlug( 'html'), undef, 'Standard "html" should not work');
+
+subtest html => sub { 
+	plan tests => 2;
+	my $lang;
+	warning_is { $lang = $hl->languagePlug( 'html') } 'undefined language: html', 'warn';
+	is($lang, undef, 'Standard "html" should not work');
+};
+
 is($hl->languagePlug( 'HTML', 1), 'HTML', 'Insesitive "HTML" should work');
-is($hl->languagePlug( 'html', 1), 'HTML', 'Insesitive "html" should work');
+
+subtest html_1 => sub {
+	plan tests => 2;
+	my $lang;
+	warning_is { $lang = $hl->languagePlug( 'html', 1) } 'substituting language HTML for html', 'warn';
+	is($lang, 'HTML', 'Insesitive "html" should work');
+};