no-assertions-in-hooks

Disallow assertions hidden inside test lifecycle hooks.

Rule details

Assertions in beforeEach, beforeAll, afterEach, or afterAll hide the behavior being verified outside the visible test case. That makes failures harder to connect to a scenario and can make a suite look well asserted even when individual tests only perform setup.

Lifecycle hooks should prepare or clean up state. Put assertions in explicit it(...) or test(...) cases with titles that explain the behavior being proved.

Incorrect

beforeEach(() => {
    expect(console.error).not.toHaveBeenCalled();
});

it("renders the widget", () => {
    renderWidget();
});

afterEach(async () => {
    await expect(closeServer()).resolves.toBeUndefined();
});

Correct

beforeEach(() => {
    vi.clearAllMocks();
});

it("renders the widget without console errors", () => {
    renderWidget();

    expect(console.error).not.toHaveBeenCalled();
});

it("closes the server cleanly", async () => {
    await expect(closeServer()).resolves.toBeUndefined();
});

What this rule reports

This rule reports direct expect(...) and expect.*(...) calls in Jest- and Vitest-style lifecycle hook callbacks:

• beforeEach
• beforeAll
• afterEach
• afterAll

Assertions inside nested helper function definitions are ignored because they do not run when the hook itself executes.

Options

This rule has no options.

When not to use it

Some teams intentionally keep suite-wide invariant checks in teardown hooks, for example verifying that a logger was not called in every test. Keep this rule in strict if that pattern is common and migrate high-value invariants into named tests when failures need clearer ownership.

Rule catalog ID: R014