test-structure-arrange-act-assert-with-setup-factories

a test that does not read as arrange, act, assert with its arrangement in a `setup()` factory

Agent checkadvisory by defaultbasetests

The argument

Test Structure — Arrange-Act-Assert with Setup Factories

Every test follows Arrange-Act-Assert, with arrangement extracted into a named setup() factory. The test body stays small: call setup, act, assert.

describe('getAvatarUrl', () => {
	test('returns the profile avatar when one exists', () => {
		const { userProfile, appSettings } = setupAvatar({ profile: 'p.png' });

		const avatarUrl = getAvatarUrl({ userProfile, appSettings });

		expect(avatarUrl).toBe('p.png');
	});
});

Rules:

The proof

failsrc/billing/getTotal.unit.test.ts

import { expect, describe, test } from '@jest/globals';
import { getTotal } from './getTotal';

describe('getTotal', () => {
	test('multiplies the quantity by the unit price', () => {
		// arrange
		const quantity = 2;
		const unitPrice = 50;
		// act and assert in one breath, with the call nested in the matcher
		expect(getTotal({ quantity, unitPrice })).toBe(100);
	});
});

passsrc/billing/getTotal.unit.test.ts

import { expect, describe, test } from '@jest/globals';
import { getTotal } from './getTotal';

const setupOrder = ({ quantity = 2, unitPrice = 50 }: { quantity?: number; unitPrice?: number } = {}) => {
	return { quantity, unitPrice };
};

describe('getTotal', () => {
	test('multiplies the quantity by the unit price', () => {
		const { quantity, unitPrice } = setupOrder();

		const total = getTotal({ quantity, unitPrice });

		expect(total).toBe(100);
	});
});

Turn it down

Both lines go in your lightsout.config.json.

"standards-checks": { "test-structure-arrange-act-assert-with-setup-factories": "advisory" }

"standards-checks": { "test-structure-arrange-act-assert-with-setup-factories": "off" }