diff --git a/Makefile.am b/Makefile.am
index 9b835e50e..7cd3ffbb9 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -96,7 +96,7 @@ common_tests_SOURCES = common.hpp common.cpp common_tests.cpp boost_unit_test.cp
 backtrack_tests_SOURCES = backtrack.hpp backtrack.cpp backtrack_tests.cpp boost_unit_test.cpp bg_helpers.hpp bg_helpers.cpp eulerian_paths.hpp eulerian_paths.cpp segmentize.hpp segmentize.cpp merge_near_points.hpp merge_near_points.cpp bg_operators.hpp bg_operators.cpp geos_helpers.hpp geos_helpers.cpp
 trim_paths_tests_SOURCES = trim_paths.hpp trim_paths.cpp trim_paths_tests.cpp boost_unit_test.cpp bg_helpers.hpp bg_helpers.cpp eulerian_paths.hpp eulerian_paths.cpp segmentize.hpp segmentize.cpp merge_near_points.hpp merge_near_points.cpp bg_operators.hpp bg_operators.cpp geos_helpers.hpp geos_helpers.cpp
 outline_bridges_tests_SOURCES = outline_bridges_tests.cpp outline_bridges.hpp outline_bridges.cpp bg_operators.hpp bg_operators.cpp bg_helpers.hpp bg_helpers.cpp eulerian_paths.hpp eulerian_paths.cpp segmentize.hpp segmentize.cpp boost_unit_test.cpp merge_near_points.hpp merge_near_points.cpp geos_helpers.hpp geos_helpers.cpp
-geos_helpers_tests_SOURCES = geos_helpers_tests.cpp geos_helpers.cpp geos_helpers.hpp boost_unit_test.cpp
+geos_helpers_tests_SOURCES = geos_helpers_tests.cpp geos_helpers.cpp geos_helpers.hpp boost_unit_test.cpp bg_operators.cpp bg_helpers.cpp eulerian_paths.cpp segmentize.cpp merge_near_points.cpp
 
 TESTS = $(check_PROGRAMS)
 
diff --git a/bg_operators.cpp b/bg_operators.cpp
index 56770d103..2d6687087 100644
--- a/bg_operators.cpp
+++ b/bg_operators.cpp
@@ -25,6 +25,7 @@ bg::model::multi_polygon<polygon_type_t> operator-(
 }
 
 template multi_polygon_type_fp operator-(const multi_polygon_type_fp&, const multi_polygon_type_fp&);
+template multi_polygon_type_fp operator-(const multi_polygon_type_fp&, const box_type_fp&);
 
 template <typename rhs_t>
 multi_polygon_type_fp operator-(const box_type_fp& lhs, const rhs_t& rhs) {
diff --git a/geos_helpers.cpp b/geos_helpers.cpp
index 0a28ff7b7..af2cb3220 100644
--- a/geos_helpers.cpp
+++ b/geos_helpers.cpp
@@ -74,12 +74,12 @@ multi_linestring_type_fp from_geos(const std::unique_ptr<geos::geom::MultiLineSt
 
 template <>
 multi_polygon_type_fp from_geos(const std::unique_ptr<geos::geom::Geometry>& g) {
-  auto mp = boost::dynamic_pointer_cast<geos::geom::MultiPolygon>(g->clone());
-  if (mp) {
+  if (dynamic_cast<geos::geom::MultiPolygon*>(g.get())) {
+    auto mp = boost::dynamic_pointer_cast<geos::geom::MultiPolygon>(g->clone());
     return from_geos(mp);
   }
+  if (dynamic_cast<geos::geom::Polygon*>(g.get())) {
   auto p = boost::dynamic_pointer_cast<geos::geom::Polygon>(g->clone());
-  if (p) {
     return multi_polygon_type_fp{from_geos(p)};
   }
   geos::io::WKTWriter writer;
diff --git a/geos_helpers_tests.cpp b/geos_helpers_tests.cpp
index 5c97feb89..9999078ce 100644
--- a/geos_helpers_tests.cpp
+++ b/geos_helpers_tests.cpp
@@ -7,30 +7,91 @@
 #ifdef GEOS_VERSION
 #include <geos/io/WKTReader.h>
 #endif // GEOS_VERSION
+#include <boost/pointer_cast.hpp>
 
 BOOST_AUTO_TEST_SUITE(geos_helpers_tests)
 
-// Confirm that both geos and boost support clockwise rings.
-BOOST_AUTO_TEST_CASE(direction) {
+BOOST_AUTO_TEST_SUITE(boost_geometry)
+
+// Holes are counter-clockwise
+BOOST_AUTO_TEST_CASE(polygon_with_holes_direction) {
   auto box = bg::return_envelope<box_type_fp>(point_type_fp(0,0));
   bg::expand(box, point_type_fp(10,10));
-  polygon_type_fp poly;
-  bg::convert(box, poly);
-  BOOST_CHECK_EQUAL(poly.outer()[1], point_type_fp(0,10));
-  bg::reverse(poly);
-  bg::correct(poly);
-  BOOST_CHECK_EQUAL(poly.outer()[1], point_type_fp(0,10));
+  auto hole = bg::return_envelope<box_type_fp>(point_type_fp(3,3));
+  bg::expand(hole, point_type_fp(7,7));
+  multi_polygon_type_fp mpoly;
+  bg::convert(box, mpoly);
+  mpoly = mpoly - hole;
+  BOOST_CHECK_EQUAL(mpoly[0].outer()[1], point_type_fp(0,10));
+  BOOST_CHECK_EQUAL(mpoly[0].inners()[0][1], point_type_fp(7,3));
+  bg::reverse(mpoly);
+  BOOST_CHECK_EQUAL(mpoly[0].outer()[1], point_type_fp(10,0));
+  BOOST_CHECK_EQUAL(mpoly[0].inners()[0][1], point_type_fp(3,7));
+  bg::correct(mpoly);
+  BOOST_CHECK_EQUAL(mpoly[0].outer()[1], point_type_fp(0,10));
+  BOOST_CHECK_EQUAL(mpoly[0].inners()[0][1], point_type_fp(7,3));
+}
+
+BOOST_AUTO_TEST_SUITE_END()
+
 #ifdef GEOS_VERSION
+
+BOOST_AUTO_TEST_SUITE(geos_geometry)
+
+BOOST_AUTO_TEST_CASE(polygon_with_holes_direction) {
   // Convert it through well-known text, which is sure to create a
   // valid polygon in geos.
   geos::io::WKTReader reader;
-  std::stringstream ss;
-  ss << bg::wkt(poly);
-  auto geos_geo = reader.read(ss.str());
-  const auto* geos_poly = dynamic_cast<geos::geom::Polygon*>(geos_geo.get());
-  BOOST_CHECK_EQUAL(geos_poly->getExteriorRing()->getPointN(1)->getX(), 0);
-  BOOST_CHECK_EQUAL(geos_poly->getExteriorRing()->getPointN(1)->getY(), 10);
-#endif // GEOS_VERSION
+  auto geos_geo = reader.read("MULTIPOLYGON(((0 0,0 10,10 10,10 0,0 0),(3 3,7 3,7 7,3 7,3 3)))");
+  auto* geos_poly = dynamic_cast<geos::geom::MultiPolygon*>(geos_geo.get());
+  geos_poly->normalize();
+  BOOST_CHECK_EQUAL(geos_poly->getGeometryN(0)->getExteriorRing()->getPointN(1)->getX(), 0);
+  BOOST_CHECK_EQUAL(geos_poly->getGeometryN(0)->getExteriorRing()->getPointN(1)->getY(), 10);
+  BOOST_CHECK_EQUAL(geos_poly->getGeometryN(0)->getInteriorRingN(0)->getPointN(1)->getX(), 7);
+  BOOST_CHECK_EQUAL(geos_poly->getGeometryN(0)->getInteriorRingN(0)->getPointN(1)->getY(), 3);
+
+  // Now convert a reversed version.
+  geos_geo = reader.read("MULTIPOLYGON(((0 0,10 0,10 10,0 10,0 0),(3 3,3 7,7 7,7 3,3 3)))");
+  geos_poly = dynamic_cast<geos::geom::MultiPolygon*>(geos_geo.get());
+  geos_poly->normalize();
+  BOOST_CHECK_EQUAL(geos_poly->getGeometryN(0)->getExteriorRing()->getPointN(1)->getX(), 0);
+  BOOST_CHECK_EQUAL(geos_poly->getGeometryN(0)->getExteriorRing()->getPointN(1)->getY(), 10);
+  BOOST_CHECK_EQUAL(geos_poly->getGeometryN(0)->getInteriorRingN(0)->getPointN(1)->getX(), 7);
+  BOOST_CHECK_EQUAL(geos_poly->getGeometryN(0)->getInteriorRingN(0)->getPointN(1)->getY(), 3);
+}
+
+BOOST_AUTO_TEST_SUITE(roundtrip)
+
+BOOST_AUTO_TEST_CASE(multi_linestring) {
+  multi_linestring_type_fp mls{{{0,0}, {1,1}}, {{2,2},{3,3}}};
+  BOOST_CHECK_EQUAL(from_geos(to_geos(mls)), mls);
+}
+
+BOOST_AUTO_TEST_CASE(linestring) {
+  linestring_type_fp ls{{0,0}, {1,1}};
+  BOOST_CHECK_EQUAL(from_geos(to_geos(ls)), ls);
+}
+
+BOOST_AUTO_TEST_CASE(polygon) {
+  polygon_type_fp poly{{{0,0}, {0,10}, {10,10}, {10,0}, {0,0}}};
+  BOOST_CHECK(bg::equals(from_geos(to_geos(poly)), poly));
 }
 
+BOOST_AUTO_TEST_CASE(ring) {
+  ring_type_fp ring{{0,0}, {0,10}, {10,10}, {10,0}, {0,0}};
+  BOOST_CHECK_EQUAL(from_geos(to_geos(ring)), ring);
+}
+
+BOOST_AUTO_TEST_SUITE_END()
+
+BOOST_AUTO_TEST_CASE(convert_multi_polygon_exception) {
+  linestring_type_fp ls{{0,0}, {1,1}};
+  auto geos_ls = boost::dynamic_pointer_cast<geos::geom::Geometry>(to_geos(ls));
+  BOOST_CHECK_THROW(from_geos<multi_polygon_type_fp>(geos_ls), std::logic_error);
+}
+
+BOOST_AUTO_TEST_SUITE_END()
+
+#endif // GEOS_VERSION
+
 BOOST_AUTO_TEST_SUITE_END()