diff --git a/src/hull_polyline2d.scad b/src/hull_polyline2d.scad
index 65a069e0..b9bfc427 100644
--- a/src/hull_polyline2d.scad
+++ b/src/hull_polyline2d.scad
@@ -24,7 +24,7 @@ module hull_polyline2d(points, width) {
         }
 
         // hook for testing
-        test_line_segment(index, point1, point2, half_width);
+        test_hull_polyline2d_line_segment(index, point1, point2, half_width);
     }
 
     module polyline2d_inner(index) {
@@ -38,6 +38,6 @@ module hull_polyline2d(points, width) {
 }
 
 // override it to test
-module test_line_segment(index, point1, point2, radius) {
+module test_hull_polyline2d_line_segment(index, point1, point2, radius) {
 
 }
\ No newline at end of file
diff --git a/test/test_hull_polyline2d.scad b/test/test_hull_polyline2d.scad
index 961d9f49..df421a1b 100644
--- a/test/test_hull_polyline2d.scad
+++ b/test/test_hull_polyline2d.scad
@@ -9,7 +9,7 @@ module test_hull_polyline2d() {
             
     include <hull_polyline2d.scad>;
     
-    module test_line_segment(index, point1, point2, radius) {
+    module test_hull_polyline2d_line_segment(index, point1, point2, radius) {
         assertEqualPoint(points[index - 1], point1);
         assertEqualPoint(points[index], point2);
         assertEqualNum(line_width, radius * 2);