db: add TestDB module

packages/db/adapters/TestDB.test.ts

@@ -0,0 +1,25 @@
+import { DittoConf } from '@ditto/conf';
+import { NPostgres } from '@nostrify/db';
+import { genEvent } from '@nostrify/nostrify/test';
+import { assertEquals } from '@std/assert';
+
+import { DittoPolyPg } from './DittoPolyPg.ts';
+import { TestDB } from './TestDB.ts';
+
+Deno.test('TestDB', async () => {
+  const conf = new DittoConf(Deno.env);
+  const orig = new DittoPolyPg(conf.databaseUrl);
+
+  await using db = new TestDB(orig);
+  await db.migrate();
+  await db.clear();
+
+  const store = new NPostgres(orig.kysely);
+  await store.event(genEvent());
+
+  assertEquals((await store.count([{}])).count, 1);
+
+  await db.clear();
+
+  assertEquals((await store.count([{}])).count, 0);
+});

packages/db/adapters/TestDB.ts

@@ -0,0 +1,49 @@
+import { type Kysely, sql } from 'kysely';
+
+import type { DittoDB } from '../DittoDB.ts';
+import type { DittoTables } from '../DittoTables.ts';
+
+/** Wraps another DittoDB implementation to clear all data when disposed. */
+export class TestDB implements DittoDB {
+  constructor(private db: DittoDB) {}
+
+  get kysely(): Kysely<DittoTables> {
+    return this.db.kysely;
+  }
+
+  get poolSize(): number {
+    return this.db.poolSize;
+  }
+
+  get availableConnections(): number {
+    return this.db.availableConnections;
+  }
+
+  migrate(): Promise<void> {
+    return this.db.migrate();
+  }
+
+  listen(channel: string, callback: (payload: string) => void): void {
+    return this.db.listen(channel, callback);
+  }
+
+  /** Truncate all tables. */
+  async clear(): Promise<void> {
+    const query = sql<{ tablename: string }>`select tablename from pg_tables where schemaname = current_schema()`;
+
+    const { rows } = await query.execute(this.db.kysely);
+
+    for (const { tablename } of rows) {
+      if (tablename.startsWith('kysely_')) {
+        continue; // Skip Kysely's internal tables
+      } else {
+        await sql`truncate table ${sql.ref(tablename)} cascade`.execute(this.db.kysely);
+      }
+    }
+  }
+
+  async [Symbol.asyncDispose](): Promise<void> {
+    await this.clear();
+    await this.db[Symbol.asyncDispose]();
+  }
+}

packages/db/mod.ts

@@ -2,6 +2,7 @@ export { DittoPglite } from './adapters/DittoPglite.ts';
 export { DittoPolyPg } from './adapters/DittoPolyPg.ts';
 export { DittoPostgres } from './adapters/DittoPostgres.ts';
 export { DummyDB } from './adapters/DummyDB.ts';
+export { TestDB } from './adapters/TestDB.ts';
 
 export type { DittoDB } from './DittoDB.ts';
 export type { DittoTables } from './DittoTables.ts';