This example demonstrates a straightforward event-sourced application.
The BankAccounts application has command and query methods for interacting with the domain model. New accounts can be opened. Existing accounts can be closed. Deposits and withdraws can be made on open accounts. Transfers can be made between open accounts, if there are sufficient funds on the debited account. All actions are atomic, including transfers between accounts.
../../../eventsourcing/examples/bankaccounts/application.py
The BankAccount aggregate class is defined using the declarative syntax <Declarative syntax>. It has a balance and an overdraft limit. Accounts can be opened and closed. Accounts can be credited and debited, which affects the balance. Neither credits nor debits are allowed if the account has been closed. Debits are not allowed if the balance would go below the overdraft limit. The overdraft limit can be adjusted.
../../../eventsourcing/examples/bankaccounts/domainmodel.py
For the purpose of showing how the application object might be used, the test runs through a scenario that exercises all the methods of the application in one test method.
../../../eventsourcing/examples/bankaccounts/test.py