feat(db): Bun.SQL Kysely dialect for sqlite and postgres

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

packages/db/src/testing.ts

@@ -0,0 +1,63 @@
+import { SQL } from "bun";
+import { afterAll, afterEach, beforeEach, describe } from "bun:test";
+import { createDb, type Db } from "./db.ts";
+import type { Dialect } from "./dialect.ts";
+import { migrateToLatest } from "./migrate.ts";
+
+/**
+ * Register `describe("<name> [<dialect>]")` for SQLite, and for Postgres when
+ * `TEST_POSTGRES_URL` is set. Every test gets a fresh, migrated database:
+ * SQLite `:memory:`, or a new `st_<random>` database on the Postgres server.
+ */
+export function forEachDialect(name: string, fn: (getDb: () => Db) => void): void {
+  const dialects: Dialect[] = ["sqlite"];
+  const pgUrl = process.env.TEST_POSTGRES_URL;
+  if (pgUrl) dialects.push("postgres");
+
+  for (const dialect of dialects) {
+    describe(`${name} [${dialect}]`, () => {
+      let current: Db | undefined;
+      const created: string[] = [];
+
+      beforeEach(async () => {
+        let url = "sqlite://:memory:";
+        if (dialect === "postgres") {
+          const dbName = `st_${crypto.randomUUID().replaceAll("-", "")}`;
+          await withAdmin(pgUrl!, (admin) => admin.unsafe(`create database "${dbName}"`));
+          created.push(dbName);
+          const u = new URL(pgUrl!);
+          u.pathname = `/${dbName}`;
+          url = u.toString();
+        }
+        current = await createDb(url);
+        await migrateToLatest(current);
+      });
+
+      afterEach(async () => {
+        await current?.close();
+        current = undefined;
+      });
+
+      afterAll(async () => {
+        if (created.length === 0) return;
+        await withAdmin(pgUrl!, async (admin) => {
+          for (const dbName of created) await admin.unsafe(`drop database if exists "${dbName}" with (force)`);
+        });
+      });
+
+      fn(() => {
+        if (!current) throw new Error("getDb() called outside a test");
+        return current;
+      });
+    });
+  }
+}
+
+async function withAdmin<T>(url: string, f: (admin: SQL) => Promise<T>): Promise<T> {
+  const admin = new SQL(url);
+  try {
+    return await f(admin);
+  } finally {
+    await admin.close();
+  }
+}