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: bridge_pool_vext.rs
    path of file: ./repos/namada/crates/apps/src/lib/node/ledger/shell/vote_extensions
    
    the code of the file until where you have to start completion: //! Extend Tendermint votes with signatures of the Ethereum
//! bridge pool root and nonce seen by a quorum of validators.
use itertools::Itertools;

use super::*;

impl<D, H> Shell<D, H>
where
    D: DB + for<'iter> DBIter<'iter> + Sync + 'static,
    H: StorageHasher + Sync + 'static,
{
    /// Takes an iterator over Bridge pool root vote extension instances,
    /// and returns another iterator. The latter yields
    /// valid Bridge pool root vote extensions, or the
    
    fn test_wrong_height_for_root() {
        let (mut shell, _recv, _, _oracle_control_recv) = setup_at_height(1u64);
        let address = shell.mode.get_validator_address().unwrap().clone();
        shell.state.in_mem_mut().block.height = 2.into();
        let key = get_key_from_hash(&KeccakHash([1; 32]));
        let height = shell.state.in_mem().block.height;
        shell.state.write(&key, height).expect("Test failed");
        shell.commit();
        assert_eq!(
            shell
                .state
                .ethbridge_queries()
                .get_bridge_pool_root_at_height(2.into())
                .unwrap(),
            KeccakHash([1; 32])
        );
        shell.state.in_mem_mut().block.height = 3.into();
        shell.state.delete(&key).expect("Test failed");
        let key = get_key_from_hash(&KeccakHash([2; 32]));
        let height = shell.state.in_mem().block.height;
        shell.state.write(&key, height).expect("Test failed");
        shell.commit();
        assert_eq!(
            shell
                .state
                .ethbridge_queries()
                .get_bridge_pool_root_at_height(3.into())
                .unwrap(),
            KeccakHash([2; 32])
        );
        let to_sign = keccak_hash([[1; 32], Uint::from(0).to_bytes()].concat());
        let sig = Signed::<_, SignableEthMessage>::new(
            shell.mode.get_eth_bridge_keypair().expect("Test failed"),
            to_sign,
        )
        .sig;
        let bp_root = bridge_pool_roots::Vext {
            block_height: 3.into(),
            validator_addr: address,
            sig,
        }
        .sign(shell.mode.get_protocol_key().expect("Test failed"));
        assert!(
            validate_bp_roots_vext(
                &shell.state,
                &bp_root.0,
                shell.get_current_decision_height()
            )
            .is_err()
        );
    }