Struct FakeLedger 

pub struct FakeLedger { /* private fields */ }

In-memory ledger for local mode execution.

Initialized with a balance derived from nanny.toml → limits.max_cost_units. Every debit reduces the balance. When balance hits zero, the policy stops execution via BudgetExhausted.

No persistence. No network. No real money. The receipts are real records — they just don’t move actual funds.

Implementations

impl FakeLedger

pub fn new(initial_balance: u64) -> Self

Create a new FakeLedger with the given initial balance.

Pass limits.max_cost_units from your nanny.toml here. That makes the budget limit and the ledger balance consistent.

Trait Implementations

impl Ledger for FakeLedger

fn authorize(&self, amount: u64) -> LedgerDecision

Check whether a spend is possible without committing to it.

Called by the executor to build PolicyContext. Does not change the balance.

fn debit(&mut self, amount: u64) -> Result<Receipt, LedgerError>

Spend amount units and return a receipt.

Reduces the balance permanently. Returns an error if the balance is insufficient.

fn balance(&self) -> u64

Current unspent balance.

fn total_debited(&self) -> u64

Total units spent across all debits.