diff --git a/iOverlay/src/vector/simplify.rs b/iOverlay/src/vector/simplify.rs
index 2de577b..4576b14 100644
--- a/iOverlay/src/vector/simplify.rs
+++ b/iOverlay/src/vector/simplify.rs
@@ -258,4 +258,79 @@ mod tests {
         debug_assert!(result);
         debug_assert!(contour.len() == 4);
     }
+
+    #[test]
+    fn test_duplicate_points() {
+        #[rustfmt::skip]
+        let mut contour = vec![
+            VectorEdge::new(1, int_pnt!(-1, 3), int_pnt!(-1, 1)),
+            VectorEdge::new(2, int_pnt!(-1, 1), int_pnt!(-1, 1)),
+            VectorEdge::new(3, int_pnt!(-1, 1), int_pnt!(-3, 1)),
+            VectorEdge::new(4, int_pnt!(-3, 1), int_pnt!(-3, -2)),
+            VectorEdge::new(5, int_pnt!(-3, -2), int_pnt!(3, -2)),
+            VectorEdge::new(6, int_pnt!(3, -2), int_pnt!(3, 1)),
+            VectorEdge::new(7, int_pnt!(3, 1), int_pnt!(3, 1)),
+            VectorEdge::new(8, int_pnt!(3, 1), int_pnt!(1, 1)),
+            VectorEdge::new(9, int_pnt!(1, 1), int_pnt!(1, 3)),
+            VectorEdge::new(10, int_pnt!(1, 3), int_pnt!(-1, 3)),
+        ];
+
+        let result = contour.simplify_contour();
+
+        debug_assert!(result);
+        debug_assert!(contour.len() == 8);
+    }
+
+    #[test]
+    fn test_tiny_segments() {
+        #[rustfmt::skip]
+        let mut contour = vec![
+            VectorEdge::new(1, int_pnt!(0, 2), int_pnt!(-1, 1)),
+            VectorEdge::new(2, int_pnt!(-1, 1), int_pnt!(-2, 0)),
+            VectorEdge::new(3, int_pnt!(-2, 0), int_pnt!(0, -1)),
+            VectorEdge::new(4, int_pnt!(0, -1), int_pnt!(2, 0)),
+            VectorEdge::new(5, int_pnt!(2, 0), int_pnt!(1, 1)),
+            VectorEdge::new(6, int_pnt!(1, 1), int_pnt!(0, 2)),
+        ];
+
+        let result = contour.simplify_contour();
+
+        debug_assert!(result);
+        debug_assert!(contour.len() == 4);
+    }
+
+    #[test]
+    fn test_collinear_runs() {
+        #[rustfmt::skip]
+        let mut contour = vec![
+            VectorEdge::new(1, int_pnt!(-2, -2), int_pnt!(0, -2)),
+            VectorEdge::new(2, int_pnt!(0, -2), int_pnt!(2, -2)),
+            VectorEdge::new(3, int_pnt!(2, -2), int_pnt!(2, 0)),
+            VectorEdge::new(4, int_pnt!(2, 0), int_pnt!(2, 2)),
+            VectorEdge::new(5, int_pnt!(2, 2), int_pnt!(0, 2)),
+            VectorEdge::new(6, int_pnt!(0, 2), int_pnt!(-2, 2)),
+            VectorEdge::new(7, int_pnt!(-2, 2), int_pnt!(-2, 0)),
+            VectorEdge::new(8, int_pnt!(-2, 0), int_pnt!(-2, -2)),
+        ];
+
+        let result = contour.simplify_contour();
+
+        debug_assert!(result);
+        debug_assert!(contour.len() == 4);
+    }
+
+    #[test]
+    fn test_zero_area_path() {
+        #[rustfmt::skip]
+        let mut contour = vec![
+            VectorEdge::new(1, int_pnt!(-3, 0), int_pnt!(0, 0)),
+            VectorEdge::new(2, int_pnt!(0, 0), int_pnt!(3, 0)),
+            VectorEdge::new(3, int_pnt!(3, 0), int_pnt!(-3, 0)),
+        ];
+
+        let result = contour.simplify_contour();
+
+        debug_assert!(result);
+        debug_assert!(contour.is_empty());
+    }
 }