Add a dedicated db crate with a basic DB trait

It's needed by the processor and tributary (coordinator).

processor/src/tests/addresses.rs

@@ -7,11 +7,13 @@ use frost::{Participant, ThresholdKeys};
 
 use tokio::time::timeout;
 
+use serai_db::MemDb;
+
 use crate::{
   Plan, Db,
   coins::{OutputType, Output, Block, Coin},
   scanner::{ScannerEvent, Scanner, ScannerHandle},
-  tests::{util::db::MemDb, sign},
+  tests::sign,
 };
 
 async fn spend<C: Coin, D: Db>(

processor/src/tests/key_gen.rs

@@ -7,6 +7,8 @@ use rand_core::{RngCore, OsRng};
 use group::GroupEncoding;
 use frost::{Participant, ThresholdParams, tests::clone_without};
 
+use serai_db::MemDb;
+
 use serai_client::{
   primitives::{MONERO_NET_ID, BlockHash},
   validator_sets::primitives::{Session, ValidatorSet},
@@ -16,7 +18,6 @@ use messages::{SubstrateContext, key_gen::*};
 use crate::{
   coins::Coin,
   key_gen::{KeyGenEvent, KeyGen},
-  tests::util::db::MemDb,
 };
 
 const ID: KeyGenId =

processor/src/tests/mod.rs

@@ -1,5 +1,3 @@
-pub(crate) mod util;
-
 mod key_gen;
 pub(crate) use key_gen::test_key_gen;
 

processor/src/tests/scanner.rs

@@ -7,10 +7,11 @@ use frost::Participant;
 
 use tokio::time::timeout;
 
+use serai_db::MemDb;
+
 use crate::{
   coins::{OutputType, Output, Block, Coin},
   scanner::{ScannerEvent, Scanner, ScannerHandle},
-  tests::util::db::MemDb,
 };
 
 pub async fn test_scanner<C: Coin>(coin: C) {

processor/src/tests/signer.rs

@@ -13,12 +13,13 @@ use frost::{
 
 use tokio::time::timeout;
 
+use serai_db::MemDb;
+
 use messages::sign::*;
 use crate::{
   Payment, Plan,
   coins::{Output, Transaction, Coin},
   signer::{SignerEvent, Signer},
-  tests::util::db::MemDb,
 };
 
 #[allow(clippy::type_complexity)]

processor/src/tests/substrate_signer.rs

@@ -17,13 +17,12 @@ use tokio::time::timeout;
 use scale::Encode;
 use sp_application_crypto::{RuntimePublic, sr25519::Public};
 
+use serai_db::MemDb;
+
 use serai_client::{primitives::*, in_instructions::primitives::*};
 
 use messages::{sign::SignId, coordinator::*};
-use crate::{
-  substrate_signer::{SubstrateSignerEvent, SubstrateSigner},
-  tests::util::db::MemDb,
-};
+use crate::substrate_signer::{SubstrateSignerEvent, SubstrateSigner};
 
 #[tokio::test]
 async fn test_substrate_signer() {

processor/src/tests/util/db.rs

@@ -1,42 +0,0 @@
-use std::{
-  sync::{Arc, RwLock},
-  collections::HashMap,
-};
-
-use crate::{DbTxn, Db};
-
-#[derive(Clone, Debug)]
-pub struct MemDb(Arc<RwLock<HashMap<Vec<u8>, Vec<u8>>>>);
-impl MemDb {
-  pub(crate) fn new() -> MemDb {
-    MemDb(Arc::new(RwLock::new(HashMap::new())))
-  }
-}
-impl Default for MemDb {
-  fn default() -> MemDb {
-    MemDb::new()
-  }
-}
-
-impl DbTxn for MemDb {
-  fn put(&mut self, key: impl AsRef<[u8]>, value: impl AsRef<[u8]>) {
-    self.0.write().unwrap().insert(key.as_ref().to_vec(), value.as_ref().to_vec());
-  }
-  fn get(&self, key: impl AsRef<[u8]>) -> Option<Vec<u8>> {
-    self.0.read().unwrap().get(key.as_ref()).cloned()
-  }
-  fn del(&mut self, key: impl AsRef<[u8]>) {
-    self.0.write().unwrap().remove(key.as_ref());
-  }
-  fn commit(self) {}
-}
-
-impl Db for MemDb {
-  type Transaction = MemDb;
-  fn txn(&mut self) -> MemDb {
-    Self(self.0.clone())
-  }
-  fn get(&self, key: impl AsRef<[u8]>) -> Option<Vec<u8>> {
-    self.0.read().unwrap().get(key.as_ref()).cloned()
-  }
-}

processor/src/tests/util/mod.rs

@@ -1 +0,0 @@
-pub(crate) mod db;

processor/src/tests/wallet.rs

@@ -6,12 +6,14 @@ use frost::{Participant, dkg::tests::key_gen};
 
 use tokio::time::timeout;
 
+use serai_db::MemDb;
+
 use crate::{
   Payment, Plan,
   coins::{Output, Transaction, Block, Coin},
   scanner::{ScannerEvent, Scanner},
   scheduler::Scheduler,
-  tests::{util::db::MemDb, sign},
+  tests::sign,
 };
 
 // Tests the Scanner, Scheduler, and Signer together