StateServiceStore Fixture for unit tests

[merl111]

Following our quick discussion on Discord:

It might come very handy if we could use a WorkNet instance in unit tests to test new features and upgrades with the actual data currently on the contract deployed to mainnet.

[devhawk]

WorkNet sits on top of StateServiceStore + PersistentTrackingStore from the Neo Blockchain Toolkit Library. I think for test purposes, we could build an xuint fixture to enable the StateServiceStore to be shared across tests. Then, in a given test you could create a MemoryTrackingStore instance on top of the StateServiceStore provided by the fixture to enable a clean environment for each test.

// assuming a StateServiceStoreFixture injected as fixture test class field 
using var store = new MemoryTrackingStore(fixture.StateServiceStore);
using var snapshot = new SnapshotCache(store.GetSnapshot());

Note, StateServiceStore requires async initialization, and I'm not sure how to do that with xuint off the top of my head