bun:test/prefer-called-once

toHaveBeenCalledTimes(1) and toHaveBeenCalledOnce() assert the same thing. This rule picks the shorter one, so the whole project writes it the same way. The alias toBeCalledTimes(1) is reported too.

--fix rewrites both to toHaveBeenCalledOnce(), because bun:test has no toBeCalledOnce().

Configure

Off by default. To turn it on:

[lint.rules]
"bun:test/prefer-called-once" = "error" # or "warn"

Examples

Reported:

import { expect, mock, test } from "bun:test";

test("notifies the listener", () => {
  const listener = mock();
  publish("ready", listener);
  expect(listener).toHaveBeenCalledTimes(1);
});

Not reported:

import { expect, mock, test } from "bun:test";

test("notifies the listener", () => {
  const listener = mock();
  publish("ready", listener);
  expect(listener).toHaveBeenCalledOnce();

  publish("done", listener);
  expect(listener).toHaveBeenCalledTimes(2);
});

When not to use it

bun:test/prefer-called-times asks for the opposite. Turn on one of the two, not both.