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: block_store_test.rs
    path of file: ./repos/diem/consensus/src/block_storage
    
    the code of the file until where you have to start completion: // Copyright (c) The Diem Core Contributors
// SPDX-License-Identifier: Apache-2.0

use crate::{
    block_storage::{block_store::sync_manager::NeedFetchResult, Block
    
fn test_illegal_timestamp() {
    let signer = ValidatorSigner::random(None);
    let block_store = build_empty_tree();
    let genesis = block_store.ordered_root();
    let block_with_illegal_timestamp = Block::new_proposal(
        vec![],
        0,
        // This timestamp is illegal, it is the same as genesis
        genesis.timestamp_usecs(),
        certificate_for_genesis(),
        &signer,
    );
    let result = block_store.execute_and_insert_block(block_with_illegal_timestamp);
    assert!(result.is_err());
}