diff --git a/test/geos_capi/tc_polygon.rb b/test/geos_capi/tc_polygon.rb
index 9b3454ff..c95cb0fa 100644
--- a/test/geos_capi/tc_polygon.rb
+++ b/test/geos_capi/tc_polygon.rb
@@ -79,6 +79,18 @@ def test_union
         end
 
 
+        def test_simplify
+          xys = [[0, 0], [5, 0], [10, 0], [10, 10], [5, 10.2], [0, 10], [0, 0]]
+          points = xys.collect { |x,y| @factory.point(x, y) }
+          poly = @factory.polygon(@factory.linear_ring(points))
+          simplified = poly.simplify(0.3)
+          new_points = simplified.exterior_ring.points
+          extra = new_points.reject { |p| [0, 10].include?(p.x) and [0, 10].include?(p.y) }
+          assert_equal 5, new_points.length, "Closed ring of the square should have 5 points"
+          assert_equal 0, extra.length , "Should only have x/y's on 0 and 10"
+        end
+
+
       end
 
     end