#[test]
    // Test that non-simplifiable log() expressions are unchanged after simplification
    fn test_log_simplify_original() {
        let props = ExecutionProps::new();
        let schema = Arc::new(DFSchema::new_with_metadata(vec![], HashMap::new()).unwrap());
        let context = SimplifyContext::new(&props).with_schema(schema);
        // One argument with no simplifications 
        let result = LogFunc::new()
            .simplify(vec![lit(2)], &context)
            .unwrap();
        match result {
            ExprSimplifyResult::Simplified(_) => panic!("Expected ExprSimplifyResult::Original"),
            ExprSimplifyResult::Original(args) => {
                assert_eq!(args.len(), 1);
                assert_eq!(args[0], lit(2));
            }
        }
        // Two arguments with no simplifications
        let result = LogFunc::new()
            .simplify(vec![lit(2), lit(3)], &context)
            .unwrap();
        match result {
            ExprSimplifyResult::Simplified(_) => panic!("Expected ExprSimplifyResult::Original"),
            ExprSimplifyResult::Original(args) => {
                assert_eq!(args.len(), 2);
                assert_eq!(args[0], lit(2));
                assert_eq!(args[1], lit(3));
            }
        }
    }