Rule proposal: Forbid afterEach etc callback with serial

[novemberborn]

This implies the callback only applies to serial tests, which is not the case. If I'm not mistaken regular test.afterEach hooks still run serially when run after a test.serial() test.

See avajs/ava#1178.

Fail

test.serial.before(fn);
test.serial.beforeEach(fn);
test.serial.afterEach(fn);
test.serial.after(fn);
test.serial.afterEach.always(fn);
test.serial.after.always(fn);

Valid

test.before(fn);
test.beforeEach(fn);
test.afterEach(fn);
test.after(fn);
test.afterEach.always(fn);
test.after.always(fn);

[sindresorhus]

It does have a purpose though:

// This would run first
test.serial.beforeEach(fn);

// Then these would run concurrently
test.beforeEach(fn);
test.beforeEach(fn);

[novemberborn]

No, hooks run in order of registration, and for serial tests they automatically run serially:

import test from 'ava'

test.beforeEach(async () => {
  console.log('1.1', new Date())
  await new Promise(resolve => setTimeout(resolve, 1000))
  console.log('1.2', new Date())
})

test.serial.beforeEach(() => {
  console.log('2', new Date())
})

test.beforeEach(async () => {
  console.log('3.1', new Date())
  await new Promise(resolve => setTimeout(resolve, 1000))
  console.log('3.2', new Date())
})

test.beforeEach(async () => {
  console.log('4.1', new Date())
  await new Promise(resolve => setTimeout(resolve, 1000))
  console.log('4.2', new Date())
})

test.serial('5', t => console.log('5', new Date()))
test('6', t => console.log('6', new Date()))
test('7', t => console.log('7', new Date()))

Gives (note the timestamps):

$ "$(npm bin)"/ava --verbose test.js

1.1 2017-01-12T16:25:58.964Z
1.2 2017-01-12T16:25:59.970Z
2 2017-01-12T16:25:59.975Z
3.1 2017-01-12T16:25:59.976Z
3.2 2017-01-12T16:26:00.981Z
4.1 2017-01-12T16:26:00.982Z
4.2 2017-01-12T16:26:01.986Z
5 2017-01-12T16:26:01.986Z
  ✔ 5
1.1 2017-01-12T16:26:01.988Z
1.1 2017-01-12T16:26:01.989Z
1.2 2017-01-12T16:26:02.994Z
1.2 2017-01-12T16:26:02.994Z
2 2017-01-12T16:26:02.995Z
2 2017-01-12T16:26:02.995Z
3.1 2017-01-12T16:26:02.995Z
3.1 2017-01-12T16:26:02.995Z
3.2 2017-01-12T16:26:04.000Z
3.2 2017-01-12T16:26:04.000Z
4.1 2017-01-12T16:26:04.001Z
4.1 2017-01-12T16:26:04.001Z
4.2 2017-01-12T16:26:05.003Z
4.2 2017-01-12T16:26:05.003Z
6 2017-01-12T16:26:05.003Z
  ✔ 6
  ✔ 7
7 2017-01-12T16:26:05.004Z

  3 tests passed [16:26:05]

[sindresorhus]

Oh, right. Then I think we should disallow that combination in AVA too, at runtime, with a user-friendly message.

[mightyiam]

No need for a rule for something that gets an error thrown, right?

[sindresorhus]

@mightyiam There is. It's useful with an early error that can be caught in the editor even before running the tests.

[novemberborn]

Oh, right. Then I think we should disallow that combination in AVA too, at runtime, with a user-friendly message.

avajs/ava#1182.

[sindresorhus]

@novemberborn I just tried test.serial.before(() => {}); in the latest AVA 1.0.0 beta and it doesn't throw.

[sindresorhus]

@novemberborn Should we close this issue in favor of #186?

[novemberborn]

Yup. test.serial.before() is now a serially-running before hook, and works as expected.