Path: Append unit tests for helix generator

src/Mod/Path/Generators/helix_generator.py

@@ -56,6 +56,11 @@ def generate(
     startPoint = edge.Vertexes[0].Point
     endPoint = edge.Vertexes[1].Point
 
+    # Swap start and end points if edge line is inverted
+    if startPoint.z < endPoint.z:
+        endPoint = edge.Vertexes[0].Point
+        startPoint = edge.Vertexes[1].Point
+
     PathLog.track(
         "(helix: <{}, {}>\n hole radius {}\n inner radius {}\n step over {}\n start point {}\n end point {}\n step_down {}\n tool diameter {}\n direction {}\n startat {})".format(
             startPoint.x,