@SuppressWarnings("unchecked")
@Test
public void testFilter8()
                        throws XMLStreamException, FactoryConfigurationError, IOException {

    Filter result = parse( "v100/testfilter8.xml" );
    OperatorFilter opFilter = (OperatorFilter) result;
    PropertyIsEqualTo prop = (PropertyIsEqualTo) opFilter.getOperator();
    Function func = (Function) prop.getParameter1();
    assertEquals( "SIN", func.getName() );
    List<Expression> params = func.getParameters();
    ValueReference propName = (ValueReference) params.get( 0 );
    assertEquals( "DISPERSION_ANGLE", propName.getAsText() );
    Literal<PrimitiveValue> lit = (Literal<PrimitiveValue>) prop.getParameter2();
    assertEquals( "1", lit.getValue().toString() );
}