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: mod.rs
    path of file: ./repos/surrealdb/core/src/fnc/script/fetch
    
    the code of the file until where you have to start completion: use std::{error::Error, fmt, sync::Arc};

use js::{Class, Ctx, Result};

mod body;
mod classes;
mod func;
mod stream;
mod util;

use classes::{Blob, FormData, Headers, Request, Response};
use func::js_fetch;

// Anoyingly errors aren't clone,
// But with how we implement streams RequestError must be clone.
/// Error returned by the request.
#[derive(Debug, Clone)]
pub enum RequestError {
	Reqwest(Arc<reqwest::Error>),
}

impl fmt::Display for RequestError {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		match *self {
			RequestError::Reqwest(ref e) => writeln!(f, "request error: {e}"
    
	async fn test_tests() {
		create_test_context!(ctx => {
			assert!(ctx.eval::<(),_>("assert(false)").is_err());
			assert!(ctx.eval::<(),_>("assert(true)").is_ok());
			assert!(ctx.eval::<(),_>("assert.eq(1,2)").is_err());
			assert!(ctx.eval::<(),_>("assert.eq(1,1)").is_ok());
			assert!(ctx.eval::<(),_>("assert.eq(1,'1')").is_ok());
			assert!(ctx.eval::<(),_>("assert.seq(1,1)").is_ok());
			assert!(ctx.eval::<(),_>("assert.seq(1,2)").is_err());
			assert!(ctx.eval::<(),_>("assert.seq(1,'1')").is_err());
			assert!(ctx.eval::<(),_>("assert.mustThrow(() => {
				// don't throw
			})").is_err());
			assert!(ctx.eval::<(),_>("assert.mustThrow(() => {
				throw new Error('an error')
			})").is_ok());
		})
		.await;
	}