diff --git a/t/combineinfill.t b/t/combineinfill.t
new file mode 100644
index 000000000..8c1ba9e77
--- /dev/null
+++ b/t/combineinfill.t
@@ -0,0 +1,71 @@
+use Test::More tests => 3;
+use strict;
+use warnings;
+
+BEGIN {
+    use FindBin;
+    use lib "$FindBin::Bin/../lib";
+}
+
+use List::Util qw(first);
+use Slic3r;
+use Slic3r::Test;
+
+{
+    my $config = Slic3r::Config->new_from_defaults;
+    $config->set('skirts', 0);
+    $config->set('solid_layers', 0);
+    $config->set('bottom_solid_layers', 0);
+    $config->set('top_solid_layers', 0);
+    $config->set('infill_every_layers', 6);
+    $config->set('layer_height', 0.06);
+    
+    my $test = sub {
+        my ($shift) = @_;
+        
+        my $self = Slic3r::Test::init_print('20mm_cube', config => $config);
+        
+        $shift /= &Slic3r::SCALING_FACTOR;
+
+        # Put a slope on the box's sides by shifting x and y coords by $tilt * (z / boxheight).
+        # The test here is to put such a slight slope on the walls that it should
+        # not trigger any extra fill on fill layers that should be empty when 
+        # combine infill is enabled.
+        $_->[0] += $shift * ($_->[2] / (20 / &Slic3r::SCALING_FACTOR)), for @{$self->objects->[0]->meshes->[0]->vertices};
+        $_->[1] += $shift * ($_->[2] / (20 / &Slic3r::SCALING_FACTOR)), for @{$self->objects->[0]->meshes->[0]->vertices};
+            
+        # copy of Print::export_gcode() up to the point 
+        # after fill surfaces are combined
+        $self->init_extruders;
+        $_->slice(keep_meshes => 1) for @{$self->objects};
+        $_->make_perimeters for @{$self->objects};
+        foreach my $layer (map @{$_->layers}, @{$self->objects}) {
+            $_->simplify(&Slic3r::SCALED_RESOLUTION)
+                for @{$layer->slices}, (map $_->expolygon, map @{$_->slices}, @{$layer->regions});
+        }
+        $_->detect_surfaces_type for @{$self->objects};
+        $_->prepare_fill_surfaces for map @{$_->regions}, map @{$_->layers}, @{$self->objects};
+        $_->process_bridges for map @{$_->regions}, map @{$_->layers}, @{$self->objects};
+        $_->discover_horizontal_shells for @{$self->objects};
+        $_->combine_infill for @{$self->objects};
+
+        # Only layers with id % 6 == 0 should have fill.
+        my $spurious_infill = 0;
+        foreach my $layer (map @{$_->layers}, @{$self->objects}) {
+            ++$spurious_infill if ($layer->id % 6 && grep @{$_->fill_surfaces} > 0, @{$layer->regions});
+        }
+
+        $spurious_infill -= scalar(@{$self->objects->[0]->layers} - 1) % 6;
+        
+        fail "spurious fill surfaces found on layers that should have none (walls " . sprintf("%.4f", Slic3r::Geometry::rad2deg(atan2($shift, 20/&Slic3r::SCALING_FACTOR))) . " degrees off vertical)"
+            unless $spurious_infill == 0;
+        1;
+    };
+    
+    # Test with mm skew offsets for the top of the 20mm-high box
+    for my $shift (0, 0.0001, 1) {
+        ok $test->($shift), "no spurious fill surfaces with box walls " . sprintf("%.4f",Slic3r::Geometry::rad2deg(atan2($shift, 20))) . " degrees off of vertical";
+    }
+}
+
+__END__