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: introspect_schema.rs
    path of file: ./repos/graphql-client/graphql_client_cli/src
    
    the code of the file until where you have to start completion: use crate::error::Error;
use crate::CliResult;
use graphql_client::GraphQLQuery;
use reqwest::
    
    fn it_parses_valid_headers() {
        // https://tools.ietf.org/html/rfc7230#section-3.2

        let expected1 = Header {
            name: "X-Name".to_string(),
            value: "Value".to_string(),
        };
        let expected2 = Header {
            name: "X-Name".to_string(),
            value: "Value:".to_string(),
        };

        for (input, expected) in [
            ("X-Name: Value", &expected1),  // ideal
            ("X-Name:Value", &expected1),   // no optional whitespace
            ("X-Name: Value ", &expected1), // with optional whitespace
            ("X-Name:\tValue", &expected1), // with optional whitespace (tab)
            ("X-Name: Value:", &expected2), // with colon in value
            // not allowed per RFC, but we'll forgive
            ("X-Name : Value", &expected1),
            (" X-Name: Value", &expected1),
        ]
        .iter()
        {
            let header = Header::from_str(input);

            assert!(header.is_ok(), "Expected ok: [{}]", input);
            assert_eq!(
                header.unwrap(),
                **expected,
                "Expected equality: [{}]",
                input
            );
        }
    }