* Drop the in-memory database
Fixes#607
This PR drops the implementation of in-memory database traits.
They are useful for testing purposes since the tests should test our codebase
and assume the database works as expected (although a follow-up PR should write
a sanity test suite for all database trait implementors).
As complexity is worth with database requirements to simplify complexity and
add more robustness, for instance, with the following plans to add support for
transactions or buffered writes, it would become more complex and
time-consuming to support a correct database trait. This PR drops the
implementation and replaces it with a SQLite memory instance
* Remove OnceCell<Mint>
Without this change, a single Mint is shared for all tests, and the first tests
to run and shutdown makes the other databases (not-reachable, as dropping the
tokio engine would also drop the database instance).
There is no real reason, other than perhaps performance. The mint should
perhaps run in their own tokio engine and share channels as API interfaces, or
a new instance should be created in each tests
* Fixed bug with foreign keys
[1] https://gist.github.com/crodas/bad00997c63bd5ac58db3c5bd90747ed
* Show more debug on failure
* Remove old code
* Remove old references to WalletMemoryDatabase
The main goal is to add a subscription to CDK Mint updates into the wallet.
This feature will be particularly useful for improving the code whenever loops
hit the mint server to check status changes.
The goal is to add an easy-to-use interface that will hide the fact that we're
connecting to WebSocket and subscribing to events. This will also hide the fact
that the CDK-mint server may not support WebSocket updates.
To be fully backward compatible, the HttpClientMethods traits have a new
method, `subscribe,` which will return an object that implements
`ActiveSubscription.`
In the primary implementation, there is a `SubscriptionClient` that will
attempt to connect through WebSocket and will fall to the HTTP-status pull and
sleep approach (the current approach), but upper stream code will receive
updates as if they come from a stream of updates through WebSocket. This
`SubscriptionClient` struct will also manage reconnections to WebSockets (with
automatic resubscriptions) and all the low-level stuff, providing an
easy-to-use interface and leaving the upper-level code with a nice interface
that is hard to misuse. When `ActiveSubscription` is dropped, it will
automatically unsubscribe.
Fixed bug with Default as described in https://github.com/cashubtc/cdk/pull/473#discussion_r1871032297
