SQLite engine: transactional seam — begin_tx, writer-slot lease, all eleven *_tx methods (task sqlite-engine-seam-tx)

alkstore-sqlite/src/store.rs

@@ -112,7 +112,12 @@ impl Store for SqliteStore {
     fn begin_tx(
         &self,
     ) -> alkstore::BoxedFuture<'_, alkstore::Result<Box<dyn alkstore::TxHandle + Send>>> {
-        Box::pin(async { Err(database_error("begin_tx wiring lands with the seam task")) })
+        let writer = self.writer.clone();
+        let db_path = self.db_path.to_string_lossy().into_owned();
+        let reopen: std::sync::Arc<
+            dyn Fn() -> alkstore::Result<rusqlite::Connection> + Send + Sync,
+        > = std::sync::Arc::new(move || crate::substrate::open_writer_connection(&db_path));
+        crate::tx::SqliteTxHandle::begin(writer, reopen)
     }
 
     fn notify<'a>(
@@ -218,3 +223,5 @@ impl Store for SqliteStore {
 
 #[cfg(test)]
 mod open_tests;
+#[cfg(test)]
+mod tx_tests;