@Test(expected = ExprEvalException.class)
public void testExec_pos1_fail() {

    NodeValue v1 = NodeValue.makeNode("<http://www.opengis.net/def/crs/EPSG/0/4326> POINT(10.0 20.0)", WKTDatatype.INSTANCE);
    NodeValue v2 = NodeValue.makeString("<http://www.opengis.net/def/crs/EPSG/0/4326> POINT(10.0 20.0001)");
    NodeValue v3 = NodeValue.makeFloat(50);
    NodeValue v4 = NodeValue.makeNode(NodeFactory.createURI(Unit_URI.KILOMETER_URL));
    NearbyFF instance = new NearbyFF();
    NodeValue expResult = NodeValue.makeBoolean(true);
    NodeValue result = instance.exec(v1, v2, v3, v4);
    //assertEquals(expResult, result);
}