Test Isolation

Each test must be independent.

Principles

1. Fresh database: Each test gets clean database state
2. No shared state: Tests don't depend on execution order
3. Setup/teardown: Use beforeAll/afterEach appropriately

Example

describe("FundService", () => {
  let services: DomainServices;

  beforeAll(async () => {
    const db = await getTestDB(); // Fresh DB
    services = createDomainServices({ db, env: {} as Env });
  });

  it("test 1", async () => {
    // Independent test
  });

  it("test 2", async () => {
    // Another independent test
  });
});