You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: serialize.rs
    path of file: ./repos/arrow-datafusion/datafusion/proto/tests/cases
    
    the code of the file until where you have to start completion: // Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the Lice
    
fn test_expression_serialization_roundtrip() {
    use datafusion_common::ScalarValue;
    use datafusion_expr::expr::ScalarFunction;
    use datafusion_expr::BuiltinScalarFunction;
    use datafusion_proto::logical_plan::from_proto::parse_expr;
    use strum::IntoEnumIterator;

    let ctx = SessionContext::new();
    let lit = Expr::Literal(ScalarValue::Utf8(None));
    for builtin_fun in BuiltinScalarFunction::iter() {
        // default to 4 args (though some exprs like substr have error checking)
        let num_args = match builtin_fun {
            BuiltinScalarFunction::Substr => 3,
            _ => 4,
        };
        let args: Vec<_> = std::iter::repeat(&lit).take(num_args).cloned().collect();
        let expr = Expr::ScalarFunction(ScalarFunction::new(builtin_fun, args));

        let extension_codec = DefaultLogicalExtensionCodec {};
        let proto = serialize_expr(&expr, &extension_codec).unwrap();
        let deserialize = parse_expr(&proto, &ctx, &extension_codec).unwrap();

        let serialize_name = extract_function_name(&expr);
        let deserialize_name = extract_function_name(&deserialize);

        assert_eq!(serialize_name, deserialize_name);
    }

    /// Extracts the first part of a function name
    /// 'foo(bar)' -> 'foo'
    fn extract_function_name(expr: &Expr) -> String {
        let name = expr.display_name().unwrap();
        name.split('(').next().unwrap().to_string()
    }
}