fn test_type_conversion()

in crates/iceberg/src/arrow/schema.rs [1608:1691]
77 lines of code
1 McCabe index (conditional complexity)

    fn test_type_conversion() {
        // test primitive type
        {
            let arrow_type = DataType::Int32;
            let iceberg_type = Type::Primitive(PrimitiveType::Int);
            assert_eq!(arrow_type, type_to_arrow_type(&iceberg_type).unwrap());
            assert_eq!(iceberg_type, arrow_type_to_type(&arrow_type).unwrap());
        }

        // test struct type
        {
            // no metadata will cause error
            let arrow_type = DataType::Struct(Fields::from(vec![
                Field::new("a", DataType::Int64, false),
                Field::new("b", DataType::Utf8, true),
            ]));
            assert_eq!(
                &arrow_type_to_type(&arrow_type).unwrap_err().to_string(),
                "DataInvalid => Field id not found in metadata"
            );

            let arrow_type = DataType::Struct(Fields::from(vec![
                Field::new("a", DataType::Int64, false).with_metadata(HashMap::from_iter([(
                    PARQUET_FIELD_ID_META_KEY.to_string(),
                    1.to_string(),
                )])),
                Field::new("b", DataType::Utf8, true).with_metadata(HashMap::from_iter([(
                    PARQUET_FIELD_ID_META_KEY.to_string(),
                    2.to_string(),
                )])),
            ]));
            let iceberg_type = Type::Struct(StructType::new(vec![
                NestedField {
                    id: 1,
                    doc: None,
                    name: "a".to_string(),
                    required: true,
                    field_type: Box::new(Type::Primitive(PrimitiveType::Long)),
                    initial_default: None,
                    write_default: None,
                }
                .into(),
                NestedField {
                    id: 2,
                    doc: None,
                    name: "b".to_string(),
                    required: false,
                    field_type: Box::new(Type::Primitive(PrimitiveType::String)),
                    initial_default: None,
                    write_default: None,
                }
                .into(),
            ]));
            assert_eq!(iceberg_type, arrow_type_to_type(&arrow_type).unwrap());
            assert_eq!(arrow_type, type_to_arrow_type(&iceberg_type).unwrap());

            // initial_default and write_default is ignored
            let iceberg_type = Type::Struct(StructType::new(vec![
                NestedField {
                    id: 1,
                    doc: None,
                    name: "a".to_string(),
                    required: true,
                    field_type: Box::new(Type::Primitive(PrimitiveType::Long)),
                    initial_default: Some(Literal::Primitive(PrimitiveLiteral::Int(114514))),
                    write_default: None,
                }
                .into(),
                NestedField {
                    id: 2,
                    doc: None,
                    name: "b".to_string(),
                    required: false,
                    field_type: Box::new(Type::Primitive(PrimitiveType::String)),
                    initial_default: None,
                    write_default: Some(Literal::Primitive(PrimitiveLiteral::String(
                        "514".to_string(),
                    ))),
                }
                .into(),
            ]));
            assert_eq!(arrow_type, type_to_arrow_type(&iceberg_type).unwrap());
        }
    }