diff --git a/include/mapnik/featureset.hpp b/include/mapnik/featureset.hpp
index e528d7de0..a6ad4e85d 100644
--- a/include/mapnik/featureset.hpp
+++ b/include/mapnik/featureset.hpp
@@ -59,7 +59,7 @@ inline featureset_ptr make_invalid_featureset()
 
 inline bool is_valid(featureset_ptr const& ptr)
 {
-    return (dynamic_cast<invalid_featureset*>(ptr.get()) == nullptr) ? false : true;
+    return (dynamic_cast<invalid_featureset*>(ptr.get()) == nullptr) ? true : false;
 }
 
 }
diff --git a/test/unit/datasource/geojson.cpp b/test/unit/datasource/geojson.cpp
index cf3214862..6d953c8bd 100644
--- a/test/unit/datasource/geojson.cpp
+++ b/test/unit/datasource/geojson.cpp
@@ -107,7 +107,7 @@ TEST_CASE("geojson") {
                 auto ds = mapnik::datasource_cache::instance().create(params);
                 CHECK(ds != nullptr);
                 auto fs = all_features(ds);
-                REQUIRE(mapnik::is_valid(fs));
+                REQUIRE(!mapnik::is_valid(fs));
                 while (auto f = fs->next())
                 {
                     CHECK(false); // shouldn't get here