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/rust-analyzer/crates/mbe/src/syntax_bridge
    
    the code of the file until where you have to start completion: use rustc_hash::FxHashMap;
use syntax::{ast, AstNode};
use test_utils::extract_annotations;
use tt::{
    buffer::{TokenBuffer, TokenTreeRef},
    Leaf, Punct, Spacing,
};

use crate::{syntax_node_to_token_tree, DummyTestSpanData, DummyTestSpanMap, DUMMY};

fn check_punct_spacing(fixture: &str) {
    let source_file = ast::SourceFile::parse(fixture).ok().unwrap();
    let subtree = syntax_node_to_token_tree(source_file.syntax(), DummyTestSpanMap, DUMMY);
    let mut annotations: FxHashMap<_, _> = extract_annotations(fixture)
        .into_iter()
        .map(|(range, annotation)| {
            let spacing = match annotation.as_str() {
                "Alone" => Spacing::Alone,
                "Joint" => Spacing::Joint,
                a => panic!("unknown annotation: {a}"),
            };
            (range, spacing)
        })
        .collect();

    let buf = TokenBuffer::from_subtree(&subtree);
    let mut cursor = buf.begin();
   
    
fn check_punct_spacing(fixture: &str) {
    let source_file = ast::SourceFile::parse(fixture).ok().unwrap();
    let subtree = syntax_node_to_token_tree(source_file.syntax(), DummyTestSpanMap, DUMMY);
    let mut annotations: FxHashMap<_, _> = extract_annotations(fixture)
        .into_iter()
        .map(|(range, annotation)| {
            let spacing = match annotation.as_str() {
                "Alone" => Spacing::Alone,
                "Joint" => Spacing::Joint,
                a => panic!("unknown annotation: {a}"),
            };
            (range, spacing)
        })
        .collect();

    let buf = TokenBuffer::from_subtree(&subtree);
    let mut cursor = buf.begin();
    while !cursor.eof() {
        while let Some(token_tree) = cursor.token_tree() {
            if let TokenTreeRef::Leaf(
                Leaf::Punct(Punct { spacing, span: DummyTestSpanData { range, .. }, .. }),
                _,
            ) = token_tree
            {
                if let Some(expected) = annotations.remove(range) {
                    assert_eq!(expected, *spacing);
                }
            }
            cursor = cursor.bump_subtree();
        }
        cursor = cursor.bump();
    }

    assert!(annotations.is_empty(), "unchecked annotations: {annotations:?}");
}