bun:test/require-hook

Require setup and teardown code to be inside a hook

Code at the top level of a test file, or directly in the body of a describe, runs once while bun test collects the tests. It runs even if every test in that block is skipped, and the state it builds is shared by all tests, so one test can break the next. Put it in beforeAll, beforeEach, afterEach or afterAll.

Two things are reported in those places:

  • a statement that's only a function call, such as setup();
  • a let or var that starts with a value other than null or undefined

const declarations are allowed. So are calls to describe, test, it and the hooks, setDefaultTimeout(), expectTypeOf(), and calls on mock, expect, jest and vi, such as mock.module() and expect.extend().

Configure#

Off by default. To turn it on:

bunfig.toml
[lint.rules]
"bun:test/require-hook" = "error" # or "warn"

Every option, set to its default:

bunfig.toml
[lint.rules]
"bun:test/require-hook" = ["error", {
  allowedFunctionCalls = [], # list of strings
}]

Examples#

example.ts3 problems
import { describe, expect, test } from "bun:test";

let db = connect();
db.seed(["ada", "grace"]);

describe("users", () => {
  clearCache();

  test("finds a user", () => {
    expect(db.find("ada")).toBeDefined();
  });
});
example.tsNo problems
import { beforeAll, beforeEach, describe, expect, mock, setDefaultTimeout, test } from "bun:test";

setDefaultTimeout(10_000);
mock.module("./mailer", () => ({ send: mock() }));

const names = ["ada", "grace"];
let db;

beforeAll(() => {
  db = connect();
  db.seed(names);
});

describe("users", () => {
  beforeEach(() => {
    clearCache();
  });

  test("finds a user", () => {
    expect(db.find("ada")).toBeDefined();
  });
});

Options#

OptionDefaultWhat it does
allowedFunctionCalls[]Names of functions that you can call outside a hook. Write a method with its object, like "db.seed".
example.tswith { "allowedFunctionCalls": ["installMatchers", "db.seed"] }No problems
import { expect, test } from "bun:test";

installMatchers();
db.seed(["ada"]);

test("finds a user", () => {
  expect(db.find("ada")).toBeUser();
});