Index: trunk/test/unit/org/openstreetmap/josm/io/GeoJSONWriterTest.java
===================================================================
--- trunk/test/unit/org/openstreetmap/josm/io/GeoJSONWriterTest.java	(revision 10805)
+++ trunk/test/unit/org/openstreetmap/josm/io/GeoJSONWriterTest.java	(revision 10817)
@@ -3,8 +3,10 @@
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
 
 import org.junit.BeforeClass;
 import org.junit.Test;
 import org.openstreetmap.josm.JOSMFixture;
+import org.openstreetmap.josm.TestUtils;
 import org.openstreetmap.josm.data.coor.LatLon;
 import org.openstreetmap.josm.data.osm.DataSet;
@@ -12,4 +14,6 @@
 import org.openstreetmap.josm.gui.layer.OsmDataLayer;
 import org.openstreetmap.josm.gui.preferences.projection.ProjectionPreference;
+
+import java.io.FileInputStream;
 
 /**
@@ -66,3 +70,16 @@
                 "}").replace("'", "\""), writer.write().trim());
     }
+
+    /**
+     * Unit test for multipolygon
+     */
+    @Test
+    public void testMultipolygon() throws Exception {
+        try (FileInputStream in = new FileInputStream(TestUtils.getTestDataRoot() + "multipolygon.osm")) {
+            DataSet ds = OsmReader.parseDataSet(in, null);
+            final OsmDataLayer layer = new OsmDataLayer(ds, "foo", null);
+            final GeoJSONWriter writer = new GeoJSONWriter(layer, ProjectionPreference.wgs84.getProjection());
+            assertTrue(writer.write().contains("MultiPolygon"));
+        }
+    }
 }