# Require setup and teardown code to be within a hook (`require-hook`)

It's common when writing tests to need to perform setup work that has to happen
before tests run, and finishing work after tests run.

Because Playwright executes all `describe` handlers in a test file _before_ it
executes any of the actual tests, it's important to ensure setup and teardown
work is done inside `before*` and `after*` handlers respectively, rather than
inside the `describe` blocks.

## Rule details

This rule flags any expression that is either at the toplevel of a test file or
directly within the body of a `describe`, _except_ for the following:

- `import` statements
- `const` variables
- `let` _declarations_, and initializations to `null` or `undefined`
- Classes
- Types
- Calls to the standard Playwright globals

This rule flags any function calls within test files that are directly within
the body of a `describe`, and suggests wrapping them in one of the four
lifecycle hooks.

Here is a slightly contrived test file showcasing some common cases that would
be flagged:

```js
const initializeCityDatabase = () => {
  database.addCity('Vienna')
  database.addCity('San Juan')
  database.addCity('Wellington')
}

const clearCityDatabase = () => {
  database.clear()
}

initializeCityDatabase()

test('that persists cities', () => {
  expect(database.cities.length).toHaveLength(3)
})

test('city database has Vienna', () => {
  expect(isCity('Vienna')).toBeTruthy()
})

test('city database has San Juan', () => {
  expect(isCity('San Juan')).toBeTruthy()
})

test.describe('when loading cities from the api', () => {
  clearCityDatabase()

  test('does not duplicate cities', async () => {
    await database.loadCities()
    expect(database.cities).toHaveLength(4)
  })
})

clearCityDatabase()
```

Here is the same slightly contrived test file showcasing the same common cases
but in ways that would be **not** flagged:

```js
const initializeCityDatabase = () => {
  database.addCity('Vienna')
  database.addCity('San Juan')
  database.addCity('Wellington')
}

const clearCityDatabase = () => {
  database.clear()
}

test.beforeEach(() => {
  initializeCityDatabase()
})

test('that persists cities', () => {
  expect(database.cities.length).toHaveLength(3)
})

test('city database has Vienna', () => {
  expect(isCity('Vienna')).toBeTruthy()
})

test('city database has San Juan', () => {
  expect(isCity('San Juan')).toBeTruthy()
})

test.describe('when loading cities from the api', () => {
  test.beforeEach(() => {
    clearCityDatabase()
  })

  test('does not duplicate cities', async () => {
    await database.loadCities()
    expect(database.cities).toHaveLength(4)
  })
})

test.afterEach(() => {
  clearCityDatabase()
})
```

## Options

If there are methods that you want to call outside of hooks and tests, you can
mark them as allowed using the `allowedFunctionCalls` option.

```json
{
  "playwright/require-hook": [
    "error",
    {
      "allowedFunctionCalls": ["enableAutoDestroy"]
    }
  ]
}
```

Examples of **correct** code when using
`{ "allowedFunctionCalls": ["enableAutoDestroy"] }` option:

```js
/* eslint playwright/require-hook: ["error", { "allowedFunctionCalls": ["enableAutoDestroy"] }] */

enableAutoDestroy(test.afterEach)

test.beforeEach(initDatabase)
test.afterEach(tearDownDatabase)

test.describe('Foo', () => {
  test('always returns 42', () => {
    expect(global.getAnswer()).toBe(42)
  })
})
```