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: tests.rs
    path of file: ./repos/rustup/src/dist/manifestation
    
    the code of the file until where you have to start completion: // Tests of installation and updates from a v2 Rust distribution
// server (mocked on the file system)
#![allow(clippy::type_complexity)]

use std::cell::Cell;
use std::collections::HashMap;
use std::env;
use std::fs;
use std::path::Path;
use std::str::FromStr;
use std::sync::Arc;

use anyhow::{anyhow, Result};
use url::Url;

use rustup_macros::unit_test as test;

use cra
    
fn upgrade() {
    setup(None, GZOnly, &|url,
                          toolchain,
                          prefix,
                          download_cfg,
                          temp_cfg| {
        change_channel_date(url, "nightly", "2016-02-01");
        update_from_dist(
            url,
            toolchain,
            prefix,
            &[],
            &[],
            download_cfg,
            temp_cfg,
            false,
        )
        .unwrap();
        assert_eq!(
            "2016-02-01",
            fs::read_to_string(prefix.path().join("bin/rustc")).unwrap()
        );
        change_channel_date(url, "nightly", "2016-02-02");
        update_from_dist(
            url,
            toolchain,
            prefix,
            &[],
            &[],
            download_cfg,
            temp_cfg,
            false,
        )
        .unwrap();
        assert_eq!(
            "2016-02-02",
            fs::read_to_string(prefix.path().join("bin/rustc")).unwrap()
        );
    });
}