private void registerMultiPositionDocumentType() {
        DocumentType x = new DocumentType("testmultipos");
        DataType d = new ArrayDataType(PositionDataType.INSTANCE);
        x.addField(new Field("multipos", d));
        x.addField(new Field("geopos", new ArrayDataType(new GeoPosType(8))));
        types.registerDocumentType(x);
    }
Functional tests for com.yahoo.document.json.JsonWriter.

@author Steinar Knutsen
document/src/test/java/com/yahoo/document/json/JsonWriterTestCase.java