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: lexical_class_tests.rs
    path of file: ./repos/rust-unic/unic/ucd/ident/tests
    
    the code of the file until where you have to start completion: // Copyright 2017 The UNIC Project Developers.
//
// See the COPYRIGHT file at the top-level directory of this distribution.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-M
    
fn test_id_derivation() {
    let other_start: BTreeSet<char> = {
        Regex::new(
            r"(?xm)^
              ([[:xdigit:]]{4,6})        # low
              (?:..([[:xdigit:]]{4,6}))? # high
              \s+;\s+
              Other_ID_Start             # property
             ",
        )
        .unwrap()
        .captures_iter(include_str!(
            "../../../../external/unicode/ucd/data/PropList.txt"
        ))
        .flat_map(|cap: regex::Captures<'_>| {
            let low = char::from_u32(u32::from_str_radix(&cap[1], 16).unwrap()).unwrap();
            let high = cap
                .get(2)
                .map(|s| u32::from_str_radix(s.as_str(), 16).unwrap())
                .map(|u| char::from_u32(u).unwrap())
                .unwrap_or(low);
            chars!(low..=high)
        })
        .collect()
    };

    let other_continue: BTreeSet<char> = {
        Regex::new(
            r"(?xm)^
              ([[:xdigit:]]{4,6})        # low
              (?:..([[:xdigit:]]{4,6}))? # high
              \s+;\s+
              Other_ID_Continue          # property
             ",
        )
        .unwrap()
        .captures_iter(include_str!(
            "../../../../external/unicode/ucd/data/PropList.txt"
        ))
        .flat_map(|cap: regex::Captures<'_>| {
            let low = char::from_u32(u32::from_str_radix(&cap[1], 16).unwrap()).unwrap();
            let high = cap
                .get(2)
                .map(|s| u32::from_str_radix(s.as_str(), 16).unwrap())
                .map(|u| char::from_u32(u).unwrap())
                .unwrap_or(low);
            chars!(low..=high)
        })
        .collect()
    };

    let is_id_start_derived = |ch| {
        let class = GeneralCategory::of(ch);
        (class.is_letter() || class == LetterNumber || other_start.contains(&ch))
            && !is_pattern_syntax(ch)
            && !is_pattern_whitespace(ch)
    };

    let is_id_continue_derived = |ch| {
        let class = GeneralCategory::of(ch);
        (matches!(
            class,
            NonspacingMark | SpacingMark | DecimalNumber | ConnectorPunctuation
        ) || is_id_start_derived(ch)
            || other_continue.contains(&ch))
            && !is_pattern_syntax(ch)
            && !is_pattern_whitespace(ch)
    };

    for ch in chars!(..) {
        assert_eq!(is_id_start(ch), is_id_start_derived(ch));
        assert_eq!(is_id_continue(ch), is_id_continue_derived(ch));
    }
}