diff -up Slic3r-1.3.0/t/gcode.t.fixtest Slic3r-1.3.0/t/gcode.t
--- Slic3r-1.3.0/t/gcode.t.fixtest	2018-06-25 11:59:06.226705956 -0400
+++ Slic3r-1.3.0/t/gcode.t	2018-06-25 11:59:42.289840358 -0400
@@ -186,6 +186,7 @@ use Slic3r::Test;
     {
         my $config = Slic3r::Config->new_from_defaults;
         $config->set('gcode_flavor', 'sailfish');
+        $config->set('layer_height', '0.4');
         my $print = Slic3r::Test::init_print('20mm_cube', config => $config, scale_xyz => [1,1, 1/(20/$config->layer_height) ]);
         $test->($print, 'one layer object');
     }