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: schema_resolution.rs
    path of file: ./repos/avrow/tests
    
    the code of the file until where you have to start completion: /// Tests for schema resolution
mod common;

use serde::{Deserialize, Serialize};

use avrow::{from_value, Codec, Read
    
fn writer_is_a_union_but_reader_is_not() {
    let writer_schema = Schema::from_str(r##"["null", "int"]"##).unwrap();
    let mut writer = writer_from_schema(&writer_schema, Codec::Deflate);
    writer.serialize(()).unwrap();
    writer.serialize(3).unwrap();

    let buf = writer.into_inner().unwrap();

    let schema_str = r##""int""##;
    let reader_schema = Schema::from_str(schema_str).unwrap();
    let mut reader = reader_with_schema(&reader_schema, buf);
    assert!(reader.next().unwrap().is_err());
    assert!(reader.next().unwrap().is_ok());
}