@Test(expected = ExprEvalException.class)
public void testExec_pos2_fail() {

    NodeValue v1 = NodeValue.makeNode("<http://www.opengis.net/def/crs/EPSG/0/4326> POINT(10.0 20.0)", WKTDatatype.INSTANCE);
    NodeValue v2 = NodeValue.makeNode("<http://www.opengis.net/def/crs/EPSG/0/4326> POINT(10.0 20.0001)", WKTDatatype.INSTANCE);
    NodeValue v3 = NodeValue.makeInteger(20);
    DistanceFF instance = new DistanceFF();
    NodeValue expResult = NodeValue.makeDouble(20);
    NodeValue result = instance.exec(v1, v2, v3);
    assertEquals(expResult, result);
}