librustzcash/zcash_client_sqlite/src/wallet.rs

//! Functions for querying information in the wdb database.

use ff::PrimeField;
use rusqlite::{params, OptionalExtension, ToSql, NO_PARAMS};
use std::collections::HashMap;

use zcash_primitives::{
    block::BlockHash,
    consensus::{self, BlockHeight, NetworkUpgrade},
    memo::Memo,
    merkle_tree::{CommitmentTree, IncrementalWitness},
    primitives::{Note, Nullifier, PaymentAddress},
    sapling::Node,
    transaction::{components::Amount, Transaction, TxId},
    zip32::ExtendedFullViewingKey,
};

use zcash_client_backend::{
    address::RecipientAddress,
    data_api::error::Error,
    encoding::{
        decode_extended_full_viewing_key, decode_payment_address, encode_extended_full_viewing_key,
        encode_payment_address,
    },
    wallet::{AccountId, WalletShieldedOutput, WalletTx},
    DecryptedOutput,
};

use crate::{error::SqliteClientError, DataConnStmtCache, NoteId, WalletDB};

pub mod init;
pub mod transact;

/// This trait provides a generalization over shielded output representations
/// that allows a wallet to avoid coupling to a specific one.
// TODO: it'd probably be better not to unify the definitions of
// `WalletShieldedOutput` and `DecryptedOutput` via a compositional
// approach, if possible.
pub trait ShieldedOutput {
    fn index(&self) -> usize;
    fn account(&self) -> AccountId;
    fn to(&self) -> &PaymentAddress;
    fn note(&self) -> &Note;
    fn memo(&self) -> Option<&Memo>;
    fn is_change(&self) -> Option<bool>;
    fn nullifier(&self) -> Option<Nullifier>;
}

impl ShieldedOutput for WalletShieldedOutput<Nullifier> {
    fn index(&self) -> usize {
        self.index
    }
    fn account(&self) -> AccountId {
        self.account
    }
    fn to(&self) -> &PaymentAddress {
        &self.to
    }
    fn note(&self) -> &Note {
        &self.note
    }
    fn memo(&self) -> Option<&Memo> {
        None
    }
    fn is_change(&self) -> Option<bool> {
        Some(self.is_change)
    }

    fn nullifier(&self) -> Option<Nullifier> {
        Some(self.nf)
    }
}

impl ShieldedOutput for DecryptedOutput {
    fn index(&self) -> usize {
        self.index
    }
    fn account(&self) -> AccountId {
        self.account
    }
    fn to(&self) -> &PaymentAddress {
        &self.to
    }
    fn note(&self) -> &Note {
        &self.note
    }
    fn memo(&self) -> Option<&Memo> {
        Some(&self.memo)
    }
    fn is_change(&self) -> Option<bool> {
        None
    }
    fn nullifier(&self) -> Option<Nullifier> {
        None
    }
}

/// Returns the address for the account.
///
/// # Examples
///
/// ```
/// use tempfile::NamedTempFile;
/// use zcash_primitives::{
///     consensus::{self, Network},
/// };
/// use zcash_client_backend::wallet::AccountId;
/// use zcash_client_sqlite::{
///     WalletDB,
///     wallet::get_address,
/// };
///
/// let data_file = NamedTempFile::new().unwrap();
/// let db = WalletDB::for_path(data_file, Network::TestNetwork).unwrap();
/// let addr = get_address(&db, AccountId(0));
/// ```
pub fn get_address<P: consensus::Parameters>(
    wdb: &WalletDB<P>,
    account: AccountId,
) -> Result<Option<PaymentAddress>, SqliteClientError> {
    let addr: String = wdb.conn.query_row(
        "SELECT address FROM accounts
        WHERE account = ?",
        &[account.0],
        |row| row.get(0),
    )?;

    decode_payment_address(wdb.params.hrp_sapling_payment_address(), &addr)
        .map_err(SqliteClientError::Bech32)
}

pub fn get_extended_full_viewing_keys<P: consensus::Parameters>(
    wdb: &WalletDB<P>,
) -> Result<HashMap<AccountId, ExtendedFullViewingKey>, SqliteClientError> {
    // Fetch the ExtendedFullViewingKeys we are tracking
    let mut stmt_fetch_accounts = wdb
        .conn
        .prepare("SELECT account, extfvk FROM accounts ORDER BY account ASC")?;

    let rows = stmt_fetch_accounts
        .query_map(NO_PARAMS, |row| {
            let acct = row.get(0).map(AccountId)?;
            let extfvk = row.get(1).map(|extfvk: String| {
                decode_extended_full_viewing_key(
                    wdb.params.hrp_sapling_extended_full_viewing_key(),
                    &extfvk,
                )
                .map_err(SqliteClientError::Bech32)
                .and_then(|k| k.ok_or(SqliteClientError::IncorrectHRPExtFVK))
            })?;

            Ok((acct, extfvk))
        })
        .map_err(SqliteClientError::from)?;

    let mut res: HashMap<AccountId, ExtendedFullViewingKey> = HashMap::new();
    for row in rows {
        let (account_id, efvkr) = row?;
        res.insert(account_id, efvkr?);
    }

    Ok(res)
}

pub fn is_valid_account_extfvk<P: consensus::Parameters>(
    wdb: &WalletDB<P>,
    account: AccountId,
    extfvk: &ExtendedFullViewingKey,
) -> Result<bool, SqliteClientError> {
    wdb.conn
        .prepare("SELECT * FROM accounts WHERE account = ? AND extfvk = ?")?
        .exists(&[
            account.0.to_sql()?,
            encode_extended_full_viewing_key(
                wdb.params.hrp_sapling_extended_full_viewing_key(),
                extfvk,
            )
            .to_sql()?,
        ])
        .map_err(SqliteClientError::from)
}

/// Returns the balance for the account, including all mined unspent notes that we know
/// about.
///
/// WARNING: This balance is potentially unreliable, as mined notes may become unmined due
/// to chain reorgs. You should generally not show this balance to users without some
/// caveat. Use [`get_balance_at`] where you need a more reliable indication of the
/// wallet balance.
///
/// # Examples
///
/// ```
/// use tempfile::NamedTempFile;
/// use zcash_primitives::consensus::Network;
/// use zcash_client_backend::wallet::AccountId;
/// use zcash_client_sqlite::{
///     WalletDB,
///     wallet::get_balance,
/// };
///
/// let data_file = NamedTempFile::new().unwrap();
/// let db = WalletDB::for_path(data_file, Network::TestNetwork).unwrap();
/// let addr = get_balance(&db, AccountId(0));
/// ```
pub fn get_balance<P>(wdb: &WalletDB<P>, account: AccountId) -> Result<Amount, SqliteClientError> {
    let balance = wdb.conn.query_row(
        "SELECT SUM(value) FROM received_notes
        INNER JOIN transactions ON transactions.id_tx = received_notes.tx
        WHERE account = ? AND spent IS NULL AND transactions.block IS NOT NULL",
        &[account.0],
        |row| row.get(0).or(Ok(0)),
    )?;

    match Amount::from_i64(balance) {
        Ok(amount) if !amount.is_negative() => Ok(amount),
        _ => Err(SqliteClientError::CorruptedData(
            "Sum of values in received_notes is out of range".to_string(),
        )),
    }
}

/// Returns the verified balance for the account at the specified height,
/// This may be used to obtain a balance that ignores notes that have been
/// received so recently that they are not yet deemed spendable.
///
/// # Examples
///
/// ```
/// use tempfile::NamedTempFile;
/// use zcash_primitives::consensus::{BlockHeight, Network};
/// use zcash_client_backend::wallet::AccountId;
/// use zcash_client_sqlite::{
///     WalletDB,
///     wallet::get_balance_at,
/// };
///
/// let data_file = NamedTempFile::new().unwrap();
/// let db = WalletDB::for_path(data_file, Network::TestNetwork).unwrap();
/// let addr = get_balance_at(&db, AccountId(0), BlockHeight::from_u32(0));
/// ```
pub fn get_balance_at<P>(
    wdb: &WalletDB<P>,
    account: AccountId,
    anchor_height: BlockHeight,
) -> Result<Amount, SqliteClientError> {
    let balance = wdb.conn.query_row(
        "SELECT SUM(value) FROM received_notes
        INNER JOIN transactions ON transactions.id_tx = received_notes.tx
        WHERE account = ? AND spent IS NULL AND transactions.block <= ?",
        &[account.0, u32::from(anchor_height)],
        |row| row.get(0).or(Ok(0)),
    )?;

    match Amount::from_i64(balance) {
        Ok(amount) if !amount.is_negative() => Ok(amount),
        _ => Err(SqliteClientError::CorruptedData(
            "Sum of values in received_notes is out of range".to_string(),
        )),
    }
}

/// Returns the memo for a received note, if it is known and a valid UTF-8 string.
///
/// The note is identified by its row index in the `received_notes` table within the wdb
/// database.
///
/// # Examples
///
/// ```
/// use tempfile::NamedTempFile;
/// use zcash_primitives::consensus::Network;
/// use zcash_client_sqlite::{
///     NoteId,
///     WalletDB,
///     wallet::get_received_memo_as_utf8,
/// };
///
/// let data_file = NamedTempFile::new().unwrap();
/// let db = WalletDB::for_path(data_file, Network::TestNetwork).unwrap();
/// let memo = get_received_memo_as_utf8(&db, 27);
/// ```
pub fn get_received_memo_as_utf8<P>(
    wdb: &WalletDB<P>,
    id_note: i64,
) -> Result<Option<String>, SqliteClientError> {
    let memo: Vec<_> = wdb.conn.query_row(
        "SELECT memo FROM received_notes
        WHERE id_note = ?",
        &[id_note],
        |row| row.get(0),
    )?;

    match Memo::from_bytes(&memo) {
        Some(memo) => match memo.to_utf8() {
            Some(Ok(res)) => Ok(Some(res)),
            Some(Err(e)) => Err(SqliteClientError::InvalidMemo(e)),
            None => Ok(None),
        },
        None => Ok(None),
    }
}

/// Returns the memo for a sent note, if it is known and a valid UTF-8 string.
///
/// The note is identified by its row index in the `sent_notes` table within the wdb
/// database.
///
/// # Examples
///
/// ```
/// use tempfile::NamedTempFile;
/// use zcash_primitives::consensus::Network;
/// use zcash_client_sqlite::{
///     NoteId,
///     WalletDB,
///     wallet::get_sent_memo_as_utf8,
/// };
///
/// let data_file = NamedTempFile::new().unwrap();
/// let db = WalletDB::for_path(data_file, Network::TestNetwork).unwrap();
/// let memo = get_sent_memo_as_utf8(&db, 12);
/// ```
pub fn get_sent_memo_as_utf8<P>(
    wdb: &WalletDB<P>,
    id_note: i64,
) -> Result<Option<String>, SqliteClientError> {
    let memo: Vec<_> = wdb.conn.query_row(
        "SELECT memo FROM sent_notes
        WHERE id_note = ?",
        &[id_note],
        |row| row.get(0),
    )?;

    match Memo::from_bytes(&memo) {
        Some(memo) => match memo.to_utf8() {
            Some(Ok(res)) => Ok(Some(res)),
            Some(Err(e)) => Err(SqliteClientError::InvalidMemo(e)),
            None => Ok(None),
        },
        None => Ok(None),
    }
}

pub fn block_height_extrema<P>(
    wdb: &WalletDB<P>,
) -> Result<Option<(BlockHeight, BlockHeight)>, rusqlite::Error> {
    wdb.conn
        .query_row(
            "SELECT MIN(height), MAX(height) FROM blocks",
            NO_PARAMS,
            |row| {
                let min_height: u32 = row.get(0)?;
                let max_height: u32 = row.get(1)?;
                Ok(Some((
                    BlockHeight::from(min_height),
                    BlockHeight::from(max_height),
                )))
            },
        )
        //.optional() doesn't work here because a failed aggregate function
        //produces a runtime error, not an empty set of rows.
        .or(Ok(None))
}

pub fn get_tx_height<P>(
    wdb: &WalletDB<P>,
    txid: TxId,
) -> Result<Option<BlockHeight>, rusqlite::Error> {
    wdb.conn
        .query_row(
            "SELECT block FROM transactions WHERE txid = ?",
            &[txid.0.to_vec()],
            |row| row.get(0).map(u32::into),
        )
        .optional()
}

pub fn get_block_hash<P>(
    wdb: &WalletDB<P>,
    block_height: BlockHeight,
) -> Result<Option<BlockHash>, rusqlite::Error> {
    wdb.conn
        .query_row(
            "SELECT hash FROM blocks WHERE height = ?",
            &[u32::from(block_height)],
            |row| {
                let row_data = row.get::<_, Vec<_>>(0)?;
                Ok(BlockHash::from_slice(&row_data))
            },
        )
        .optional()
}

/// Rewinds the database to the given height.
///
/// If the requested height is greater than or equal to the height of the last scanned
/// block, this function does nothing.
///
/// This should only be executed inside a transactional context.
pub fn rewind_to_height<P: consensus::Parameters>(
    wdb: &WalletDB<P>,
    block_height: BlockHeight,
) -> Result<(), SqliteClientError> {
    let sapling_activation_height = wdb
        .params
        .activation_height(NetworkUpgrade::Sapling)
        .ok_or(SqliteClientError::BackendError(Error::SaplingNotActive))?;

    // Recall where we synced up to previously.
    let last_scanned_height =
        wdb.conn
            .query_row("SELECT MAX(height) FROM blocks", NO_PARAMS, |row| {
                row.get(0)
                    .map(|h: u32| h.into())
                    .or(Ok(sapling_activation_height - 1))
            })?;

    // nothing to do if we're deleting back down to the max height
    if block_height >= last_scanned_height {
        Ok(())
    } else {
        // Decrement witnesses.
        wdb.conn.execute(
            "DELETE FROM sapling_witnesses WHERE block > ?",
            &[u32::from(block_height)],
        )?;

        // Un-mine transactions.
        wdb.conn.execute(
            "UPDATE transactions SET block = NULL, tx_index = NULL WHERE block > ?",
            &[u32::from(block_height)],
        )?;

        // Now that they aren't depended on, delete scanned blocks.
        wdb.conn.execute(
            "DELETE FROM blocks WHERE height > ?",
            &[u32::from(block_height)],
        )?;

        Ok(())
    }
}

pub fn get_commitment_tree<P>(
    wdb: &WalletDB<P>,
    block_height: BlockHeight,
) -> Result<Option<CommitmentTree<Node>>, SqliteClientError> {
    wdb.conn
        .query_row_and_then(
            "SELECT sapling_tree FROM blocks WHERE height = ?",
            &[u32::from(block_height)],
            |row| {
                let row_data: Vec<u8> = row.get(0)?;
                CommitmentTree::read(&row_data[..]).map_err(|e| {
                    rusqlite::Error::FromSqlConversionFailure(
                        row_data.len(),
                        rusqlite::types::Type::Blob,
                        Box::new(e),
                    )
                })
            },
        )
        .optional()
        .map_err(SqliteClientError::from)
}

pub fn get_witnesses<P>(
    wdb: &WalletDB<P>,
    block_height: BlockHeight,
) -> Result<Vec<(NoteId, IncrementalWitness<Node>)>, SqliteClientError> {
    let mut stmt_fetch_witnesses = wdb
        .conn
        .prepare("SELECT note, witness FROM sapling_witnesses WHERE block = ?")?;
    let witnesses = stmt_fetch_witnesses
        .query_map(&[u32::from(block_height)], |row| {
            let id_note = NoteId::ReceivedNoteId(row.get(0)?);
            let wdb: Vec<u8> = row.get(1)?;
            Ok(IncrementalWitness::read(&wdb[..]).map(|witness| (id_note, witness)))
        })
        .map_err(SqliteClientError::from)?;

    // unwrap database error & IO error from IncrementalWitness::read
    let res: Vec<_> = witnesses.collect::<Result<Result<_, _>, _>>()??;
    Ok(res)
}

pub fn get_nullifiers<P>(
    wdb: &WalletDB<P>,
) -> Result<Vec<(AccountId, Nullifier)>, SqliteClientError> {
    // Get the nullifiers for the notes we are tracking
    let mut stmt_fetch_nullifiers = wdb
        .conn
        .prepare("SELECT id_note, account, nf FROM received_notes WHERE spent IS NULL")?;
    let nullifiers = stmt_fetch_nullifiers.query_map(NO_PARAMS, |row| {
        let account = AccountId(row.get(1)?);
        let nf_bytes: Vec<u8> = row.get(2)?;
        Ok((account, Nullifier::from_slice(&nf_bytes).unwrap()))
    })?;

    let res: Vec<_> = nullifiers.collect::<Result<_, _>>()?;
    Ok(res)
}

pub fn insert_block<'a, P>(
    stmts: &mut DataConnStmtCache<'a, P>,
    block_height: BlockHeight,
    block_hash: BlockHash,
    block_time: u32,
    commitment_tree: &CommitmentTree<Node>,
) -> Result<(), SqliteClientError> {
    let mut encoded_tree = Vec::new();
    commitment_tree.write(&mut encoded_tree).unwrap();

    stmts.stmt_insert_block.execute(params![
        u32::from(block_height),
        &block_hash.0[..],
        block_time,
        encoded_tree
    ])?;

    Ok(())
}

pub fn put_tx_meta<'a, P, N>(
    stmts: &mut DataConnStmtCache<'a, P>,
    tx: &WalletTx<N>,
    height: BlockHeight,
) -> Result<i64, SqliteClientError> {
    let txid = tx.txid.0.to_vec();
    if stmts
        .stmt_update_tx_meta
        .execute(params![u32::from(height), (tx.index as i64), txid])?
        == 0
    {
        // It isn't there, so insert our transaction into the database.
        stmts
            .stmt_insert_tx_meta
            .execute(params![txid, u32::from(height), (tx.index as i64),])?;

        Ok(stmts.wallet_db.conn.last_insert_rowid())
    } else {
        // It was there, so grab its row number.
        stmts
            .stmt_select_tx_ref
            .query_row(&[txid], |row| row.get(0))
            .map_err(SqliteClientError::from)
    }
}

pub fn put_tx_data<'a, P>(
    stmts: &mut DataConnStmtCache<'a, P>,
    tx: &Transaction,
    created_at: Option<time::OffsetDateTime>,
) -> Result<i64, SqliteClientError> {
    let txid = tx.txid().0.to_vec();

    let mut raw_tx = vec![];
    tx.write(&mut raw_tx)?;

    if stmts
        .stmt_update_tx_data
        .execute(params![u32::from(tx.expiry_height), raw_tx, txid,])?
        == 0
    {
        // It isn't there, so insert our transaction into the database.
        stmts.stmt_insert_tx_data.execute(params![
            txid,
            created_at,
            u32::from(tx.expiry_height),
            raw_tx
        ])?;

        Ok(stmts.wallet_db.conn.last_insert_rowid())
    } else {
        // It was there, so grab its row number.
        stmts
            .stmt_select_tx_ref
            .query_row(&[txid], |row| row.get(0))
            .map_err(SqliteClientError::from)
    }
}

pub fn mark_spent<'a, P>(
    stmts: &mut DataConnStmtCache<'a, P>,
    tx_ref: i64,
    nf: &Nullifier,
) -> Result<(), SqliteClientError> {
    stmts
        .stmt_mark_recived_note_spent
        .execute(&[tx_ref.to_sql()?, nf.0.to_sql()?])?;
    Ok(())
}

// Assumptions:
// - A transaction will not contain more than 2^63 shielded outputs.
// - A note value will never exceed 2^63 zatoshis.
pub fn put_received_note<'a, P, T: ShieldedOutput>(
    stmts: &mut DataConnStmtCache<'a, P>,
    output: &T,
    tx_ref: i64,
) -> Result<NoteId, SqliteClientError> {
    let rcm = output.note().rcm().to_repr();
    let account = output.account().0 as i64;
    let diversifier = output.to().diversifier().0.to_vec();
    let value = output.note().value as i64;
    let rcm = rcm.as_ref();
    let memo = output.memo().map(|m| m.as_bytes());
    let is_change = output.is_change();
    let tx = tx_ref;
    let output_index = output.index() as i64;
    let nf_bytes = output.nullifier().map(|nf| nf.0.to_vec());

    let sql_args: &[(&str, &dyn ToSql)] = &[
        (&":account", &account),
        (&":diversifier", &diversifier),
        (&":value", &value),
        (&":rcm", &rcm),
        (&":nf", &nf_bytes),
        (&":memo", &memo),
        (&":is_change", &is_change),
        (&":tx", &tx),
        (&":output_index", &output_index),
    ];

    // First try updating an existing received note into the database.
    if stmts.stmt_update_received_note.execute_named(&sql_args)? == 0 {
        // It isn't there, so insert our note into the database.
        stmts.stmt_insert_received_note.execute_named(&sql_args)?;

        Ok(NoteId::ReceivedNoteId(
            stmts.wallet_db.conn.last_insert_rowid(),
        ))
    } else {
        // It was there, so grab its row number.
        stmts
            .stmt_select_received_note
            .query_row(params![tx_ref, (output.index() as i64)], |row| {
                row.get(0).map(NoteId::ReceivedNoteId)
            })
            .map_err(SqliteClientError::from)
    }
}

pub fn insert_witness<'a, P>(
    stmts: &mut DataConnStmtCache<'a, P>,
    note_id: i64,
    witness: &IncrementalWitness<Node>,
    height: BlockHeight,
) -> Result<(), SqliteClientError> {
    let mut encoded = Vec::new();
    witness.write(&mut encoded).unwrap();

    stmts
        .stmt_insert_witness
        .execute(params![note_id, u32::from(height), encoded])?;

    Ok(())
}

pub fn prune_witnesses<'a, P>(
    stmts: &mut DataConnStmtCache<'a, P>,
    below_height: BlockHeight,
) -> Result<(), SqliteClientError> {
    stmts
        .stmt_prune_witnesses
        .execute(&[u32::from(below_height)])?;
    Ok(())
}

pub fn update_expired_notes<'a, P>(
    stmts: &mut DataConnStmtCache<'a, P>,
    height: BlockHeight,
) -> Result<(), SqliteClientError> {
    stmts.stmt_update_expired.execute(&[u32::from(height)])?;
    Ok(())
}

pub fn put_sent_note<'a, P: consensus::Parameters>(
    stmts: &mut DataConnStmtCache<'a, P>,
    output: &DecryptedOutput,
    tx_ref: i64,
) -> Result<(), SqliteClientError> {
    let output_index = output.index as i64;
    let account = output.account.0 as i64;
    let value = output.note.value as i64;
    let to_str = encode_payment_address(
        stmts.wallet_db.params.hrp_sapling_payment_address(),
        &output.to,
    );

    // Try updating an existing sent note.
    if stmts.stmt_update_sent_note.execute(params![
        account,
        to_str,
        value,
        &output.memo.as_bytes(),
        tx_ref,
        output_index
    ])? == 0
    {
        // It isn't there, so insert.
        insert_sent_note(
            stmts,
            tx_ref,
            output.index,
            output.account,
            &RecipientAddress::Shielded(output.to.clone()),
            Amount::from_u64(output.note.value)
                .map_err(|_| SqliteClientError::CorruptedData("Note value invalid.".to_string()))?,
            &Some(output.memo.clone()),
        )?
    }

    Ok(())
}

pub fn insert_sent_note<'a, P: consensus::Parameters>(
    stmts: &mut DataConnStmtCache<'a, P>,
    tx_ref: i64,
    output_index: usize,
    account: AccountId,
    to: &RecipientAddress,
    value: Amount,
    memo: &Option<Memo>,
) -> Result<(), SqliteClientError> {
    let to_str = to.encode(&stmts.wallet_db.params);
    let ivalue: i64 = value.into();
    stmts.stmt_insert_sent_note.execute(params![
        tx_ref,
        (output_index as i64),
        account.0,
        to_str,
        ivalue,
        memo.as_ref().map(|m| m.as_bytes().to_vec()),
    ])?;

    Ok(())
}

#[cfg(test)]
mod tests {
    use tempfile::NamedTempFile;

    use zcash_primitives::{
        transaction::components::Amount,
        zip32::{ExtendedFullViewingKey, ExtendedSpendingKey},
    };

    use zcash_client_backend::data_api::WalletRead;

    use crate::{
        tests,
        wallet::init::{init_accounts_table, init_wallet_db},
        AccountId, WalletDB,
    };

    use super::{get_address, get_balance};

    #[test]
    fn empty_database_has_no_balance() {
        let data_file = NamedTempFile::new().unwrap();
        let db_data = WalletDB::for_path(data_file.path(), tests::network()).unwrap();
        init_wallet_db(&db_data).unwrap();

        // Add an account to the wallet
        let extsk = ExtendedSpendingKey::master(&[]);
        let extfvks = [ExtendedFullViewingKey::from(&extsk)];
        init_accounts_table(&db_data, &extfvks).unwrap();

        // The account should be empty
        assert_eq!(get_balance(&db_data, AccountId(0)).unwrap(), Amount::zero());

        // We can't get an anchor height, as we have not scanned any blocks.
        assert_eq!((&db_data).get_target_and_anchor_heights().unwrap(), None);

        // An invalid account has zero balance
        assert!(get_address(&db_data, AccountId(1)).is_err());
        assert_eq!(get_balance(&db_data, AccountId(0)).unwrap(), Amount::zero());
    }
}