diff --git a/test/unit/datasource/geojson.cpp b/test/unit/datasource/geojson.cpp
index 05cd55d03..6d513bd02 100644
--- a/test/unit/datasource/geojson.cpp
+++ b/test/unit/datasource/geojson.cpp
@@ -29,9 +29,10 @@
 #include <mapnik/geometry.hpp>
 #include <mapnik/geometry/geometry_type.hpp>
 #include <mapnik/json/geometry_parser.hpp>
+#include <mapnik/util/geometry_to_geojson.hpp>
 #include <mapnik/util/fs.hpp>
 #include <cstdlib>
-
+#include <algorithm>
 #include <boost/optional/optional_io.hpp>
 
 /*
@@ -128,10 +129,19 @@ TEST_CASE("geojson") {
                     "{ \"type\": \"MultiPolygon\", \"coordinates\": [[ []] ] }"
                 };
 
-            for (auto const& json  : valid_empty_geometries)
+            for (auto const& in  : valid_empty_geometries)
             {
+                std::string json(in);
                 mapnik::geometry::geometry<double> geom;
                 CHECK(mapnik::json::from_geojson(json, geom));
+                // round trip
+                std::string json_out;
+                CHECK(mapnik::util::to_geojson(json_out, geom));
+                json.erase(std::remove_if(
+                               std::begin(json), std::end(json),
+                               [l = std::locale{}](auto ch) { return std::isspace(ch, l); }
+                               ), std::end(json));
+                REQUIRE(json == json_out);
             }
 
             auto invalid_empty_geometries =