@Test
public void testInstanceOfExpressionFunction() {

    String inputExpression = "duration instance of function";
    BaseNode instanceOfBase = parse( inputExpression );
    assertThat( instanceOfBase, is( instanceOf( InstanceOfNode.class ) ) );
    assertThat( instanceOfBase.getText(), is( inputExpression ) );
    assertThat( instanceOfBase.getResultType(), is( BuiltInType.BOOLEAN ) );
    InstanceOfNode ioExpr = (InstanceOfNode) instanceOfBase;
    assertThat( ioExpr.getExpression(), is( instanceOf( NameRefNode.class ) ) );
    assertThat( ioExpr.getExpression().getText(), is( "duration" ) );
    assertThat( ioExpr.getType(), is( instanceOf( TypeNode.class ) ) );
    assertThat( ioExpr.getType().getText(), is( "function" ) );
}