@farbenmeer/prisma-migrate-test

Factory functions for creating isolated test databases using the template-clone pattern: migrations run once to build a template, then each test gets a cheap clone — no repeated migration overhead.

Installation

npm install @farbenmeer/prisma-migrate-test

SQLite

Peer dependencies

npm install better-sqlite3 @prisma/adapter-better-sqlite3
npm install -D @types/better-sqlite3

Usage

import { createSqliteTestDb } from "@farbenmeer/prisma-migrate-test/sqlite";
import { PrismaClient } from "@prisma/client";
import { afterAll, afterEach, beforeAll, beforeEach } from "vitest";

let testDb: SqliteTestDb;
let prisma: PrismaClient;

beforeAll(() => {
  testDb = createSqliteTestDb({ migrationsPath: "prisma/migrations" });
});

afterAll(() => {
  testDb.cleanup();
});

beforeEach(async () => {
  prisma = new PrismaClient({ adapter: await testDb.getAdapter() });
});

afterEach(async () => {
  await prisma.$disconnect();
});

API

createSqliteTestDb(options?): SqliteTestDb

Runs all migrations once into an in-memory template, then provides cheap per-test clones written to a temp directory.

Parameters:

• options.migrationsPath — path to the Prisma migrations folder (default: "prisma/migrations")

Returns: SqliteTestDb

• getAdapter(): Promise<PrismaBetterSqlite3> — writes a clone of the template to disk and returns a new adapter backed by it
• cleanup(): void — deletes the temp directory

PGlite

Peer dependencies

npm install @electric-sql/pglite pglite-prisma-adapter

Usage

Configure your Prisma schema to use the postgresql provider and generate the client with the pglite previewFeature.

import { createPgliteTestDb } from "@farbenmeer/prisma-migrate-test/pglite";
import { PrismaClient } from "@prisma/client";
import { afterAll, afterEach, beforeAll, beforeEach } from "vitest";

let testDb: PgliteTestDb;
let prisma: PrismaClient;

beforeAll(() => {
  testDb = createPgliteTestDb({ migrationsPath: "prisma/migrations" });
});

afterAll(async () => {
  await testDb.cleanup();
});

beforeEach(async () => {
  prisma = new PrismaClient({ adapter: await testDb.getAdapter() });
});

afterEach(async () => {
  await prisma.$disconnect();
});

API

createPgliteTestDb(options?): PgliteTestDb

Runs all migrations once into an in-memory PGlite instance and dumps the result, then provides cheap per-test clones restored from that dump.

Parameters:

• options.migrationsPath — path to the Prisma migrations folder (default: "prisma/migrations")
• options.extensions — PGlite extensions to pass to each instance (default: {})
• options.seed — optional seed data applied after migrations. Pass a SQL string or an async function (adapter: PrismaPGlite) => Promise<void> to seed via Prisma. The seed runs once when the template is built, so every clone includes the seeded data.

Returns: PgliteTestDb

• getAdapter(): Promise<PrismaPGlite & { reset(): Promise<void> }> — restores a clone from the dump and returns a new adapter with a reset() method that truncates all public tables
• cleanup(): Promise<void> — closes all open PGlite instances

Seeding

// Seed with raw SQL
const testDb = createPgliteTestDb({
  seed: `INSERT INTO "User" (email, name) VALUES ('[email protected]', 'Alice')`,
});

// Seed with a function (uses the Prisma adapter)
const testDb = createPgliteTestDb({
  seed: async (adapter) => {
    const prisma = new PrismaClient({ adapter });
    await prisma.user.create({ data: { email: "[email protected]", name: "Alice" } });
    await prisma.$disconnect();
  },
});

Resetting between tests

The adapter returned by getAdapter() includes a reset() method that truncates all public tables (except _prisma_migrations):

const adapter = await testDb.getAdapter();
const prisma = new PrismaClient({ adapter });

// ... run test ...

await adapter.reset(); // truncates all tables

License

MIT