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: error.rs
    path of file: ./repos/holochain-rust/crates/conductor_lib/src
    
    the code of the file until where you have to start completion: use holochain_core_types::error::HolochainError;
use std::{error::Error, fmt, option::NoneError};

pub type HolochainResult<T> = Result<T, HolochainInstanceError>;

// TODO rename to HolochainError
#[derive(Debug, PartialEq, Clone)]
pub enum HolochainInstanceError {
    InternalFailure(HolochainError),
    InstanceNotActiveYet,
    InstanceAlreadyActive,
    InstanceNotInitialized,
    NoSuchInstance,
    RequiredBridgeMissing(String),
}

impl Error for HolochainInstanceError {
    // not sure how to test t
    
    fn holochain_instance_error_to_string_test() {
        for (i, o) in vec![
            (
                HolochainInstanceError::InstanceNotInitialized,
                "Holochain instance is not initialized.",
            ),
            (
                HolochainInstanceError::InstanceNotActiveYet,
                "Holochain instance is not active yet.",
            ),
            (
                HolochainInstanceError::InstanceAlreadyActive,
                "Holochain instance is already active.",
            ),
            (
                HolochainInstanceError::InternalFailure(HolochainError::DnaMissing),
                "DNA is missing",
            ),
            (
                HolochainInstanceError::NoSuchInstance,
                "Instance does not exist",
            ),
            (
                HolochainInstanceError::RequiredBridgeMissing(String::from("handle")),
                &format!("Required bridge is not present/started: handle"),
            ),
        ] {
            assert_eq!(
                i.to_string(),
                format!("Holochain Instance Error: {}", o).to_string(),
            );
        }
    }