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: tools.rs
    path of file: ./repos/cargo/crates/cargo-test-support/src
    
    the code of the file until where you have to start completion: //! Common executables that can be reused by various tests.

use crate::{basic_manifest, paths, project, Project};
use std::path::{Path, PathBuf};
use std::sync::Mutex;
use std::sync::OnceLock;

static ECHO_WRAPPER: OnceLock<Mutex<Option<PathBuf>>> = OnceLock::new();
static ECHO: OnceLock<Mutex<Option<PathBuf>>> = OnceLock::new();
static CLIPPY_DRIVER: OnceLock<Mutex<Option<PathBuf>>> = OnceLock::new();

/// Returns the path to an executable that works as a wrapper around rustc.
///
/// The wrapper will echo the command line it was called with to stderr.
pub fn echo_wrapper() -> PathBuf {
    let mut lock = ECHO_WRAPPER
        .get_or_init(|| Default::default())
        .lock()
        .unwrap();
    if let Some(path) = &*lock {
        return path.clone();
    }
    let p = project()
      
    
pub fn echo() -> PathBuf {
    let mut lock = ECHO.get_or_init(|| Default::default()).lock().unwrap();
    if let Some(path) = &*lock {
        return path.clone();
    }
    if let Ok(path) = cargo_util::paths::resolve_executable(Path::new("echo")) {
        *lock = Some(path.clone());
        return path;
    }
    // Often on Windows, `echo` is not available.
    let p = project()
        .at(paths::global_root().join("basic-echo"))
        .file("Cargo.toml", &basic_manifest("basic-echo", "1.0.0"))
        .file(
            "src/main.rs",
            r#"
                fn main() {
                    let mut s = String::new();
                    let mut it = std::env::args().skip(1).peekable();
                    while let Some(n) = it.next() {
                        s.push_str(&n);
                        if it.peek().is_some() {
                            s.push(' ');
                        }
                    }
                    println!("{}", s);
                }
            "#,
        )
        .build();
    p.cargo("build").run();
    let path = p.bin("basic-echo");
    *lock = Some(path.clone());
    path
}