diff --git a/test/bug.calc.t b/test/bug.calc.t
index 47fd837a3..50587462c 100755
--- a/test/bug.calc.t
+++ b/test/bug.calc.t
@@ -29,13 +29,15 @@ use strict;
 use warnings;
 use Test::More tests => 5;
 
+my $ut = 'bug.calc.t';
+
 # '15min' is seen as '15', 'min', not '15min' duration.
 my $output = qx{../src/calc --debug --noambiguous 15min};
-unlike ($output, qr/token infix '15' Date/,           'Misinterpretation: 15min -> 15');
-unlike ($output, qr/token infix 'min' Identifier/,    'Misinterpretation: 15min -> m');
-unlike ($output, qr/Error: Unexpected stack size: 2/, 'Unexpected stack size');
-like ($output, qr/\[0\] eval push 'PT15M'/,           '15min -> push PT15M');
-like ($output, qr/^PT15M$/ms,                         '15min -> PT15M');
+unlike ($output, qr/token infix '15' Date/,           "$ut: Misinterpretation: 15min -> 15");
+unlike ($output, qr/token infix 'min' Identifier/,    "$ut: Misinterpretation: 15min -> m");
+unlike ($output, qr/Error: Unexpected stack size: 2/, "$ut: Unexpected stack size");
+like ($output, qr/\[0\] eval push 'PT15M'/,           "$ut: 15min -> push PT15M");
+like ($output, qr/^PT15M$/ms,                         "$ut: 15min -> PT15M");
 
 exit 0;