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: constant_test.rs
    path of file: ./repos/gdext/itest/rust/src/register_tests
    
    the code of the file until where you have to start completion: /*
 * Copyright (c) godot-rust; Bromeon and contributors.
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/.
 */

// Needed for Clippy to accept #[cfg(all())]
#![allow(clippy::non_minimal_cfg)]

use crate::framework::itest;
use godot::engine::ClassDb;
use godot::prelude::*;
use godot::sys::static_assert;

#[derive(GodotClass)]
#[class(no_init)]
struct HasConstants {}

#[godot_api]
impl HasConstants {
    #[constant]
    const A: i64 = 128;

    #[constant]
    const B: i128 = -600;

    #[constant]
    
fn constants_correct_value() {
    const CONSTANTS: [(&str, i64); 5] = [
        ("A", HasConstants::A),
        ("B", HasConstants::B as i64),
        ("C", HasConstants::C as i64),
        ("D", HasConstants::D as i64),
        (
            "CFG_REMOVES_DUPLICATE_CONSTANT_DEF",
            HasConstants::CFG_REMOVES_DUPLICATE_CONSTANT_DEF,
        ),
    ];

    let constants = ClassDb::singleton()
        .class_get_integer_constant_list_ex(HasConstants::class_name().to_string_name())
        .no_inheritance(true)
        .done();

    for (constant_name, constant_value) in CONSTANTS {
        assert!(constants.contains(constant_name.into()));
        assert_eq!(
            ClassDb::singleton().class_get_integer_constant(
                HasConstants::class_name().to_string_name(),
                constant_name.into()
            ),
            constant_value
        );
    }

    // Ensure the constants are still present and are equal to 'true'
    static_assert!(HasConstants::CONSTANT_RECOGNIZED_WITH_SIMPLE_PATH_ATTRIBUTE_ABOVE_CONST_ATTR);
    static_assert!(HasConstants::CONSTANT_RECOGNIZED_WITH_SIMPLE_PATH_ATTRIBUTE_BELOW_CONST_ATTR);
}