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feat(no-done-callback): support hooks (#656)
BREAKING CHANGE: `no-done-callback` will now report hooks using callbacks as well, not just tests Fixes #649 Resolves #651
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‎README.md

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@@ -138,7 +138,7 @@ installations requiring long-term consistency.
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| [no-conditional-expect](docs/rules/no-conditional-expect.md) | Prevent calling `expect` conditionally | ![recommended][] | |
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| [no-deprecated-functions](docs/rules/no-deprecated-functions.md) | Disallow use of deprecated functions | ![recommended][] | ![fixable][] |
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| [no-disabled-tests](docs/rules/no-disabled-tests.md) | Disallow disabled tests | ![recommended][] | |
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| [no-done-callback](docs/rules/no-done-callback.md) | Avoid using a callback in asynchronous tests | ![recommended][] | ![suggest][] |
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| [no-done-callback](docs/rules/no-done-callback.md) | Avoid using a callback in asynchronous tests and hooks | ![recommended][] | ![suggest][] |
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| [no-duplicate-hooks](docs/rules/no-duplicate-hooks.md) | Disallow duplicate setup and teardown hooks | | |
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| [no-export](docs/rules/no-export.md) | Disallow using `exports` in files containing tests | ![recommended][] | |
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| [no-focused-tests](docs/rules/no-focused-tests.md) | Disallow focused tests | ![recommended][] | ![fixable][] |

‎docs/rules/no-done-callback.md

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# Avoid using a callback in asynchronous tests (`no-done-callback`)
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# Avoid using a callback in asynchronous tests and hooks (`no-done-callback`)
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Jest allows you to pass a callback to test definitions, typically called `done`,
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that is later invoked to indicate that the asynchronous test is complete.
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When calling asynchronous code in hooks and tests, `jest` needs to know when the
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asynchronous work is complete to progress the current run.
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However, that means that if your test throws (e.g. because of a failing
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assertion), `done` will never be called unless you manually use `try-catch`.
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Originally the most common pattern to archive this was to use callbacks:
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```js
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test('some test', done => {
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expect(false).toBe(true);
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done();
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test('the data is peanut butter', done => {
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function callback(data) {
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try {
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expect(data).toBe('peanut butter');
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done();
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} catch (error) {
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done(error);
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}
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}
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fetchData(callback);
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});
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```
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The test above will time out instead of failing the assertions, since `done` is
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never called.
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This can be very error prone however, as it requires careful understanding of
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how assertions work in tests or otherwise tests won't behave as expected.
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Correct way of doing the same thing is to wrap it in `try-catch`.
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For example, if the `try/catch` was left out of the above code, the test would
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timeout rather than fail. Even with the `try/catch`, forgetting to pass the
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caught error to `done` will result in `jest` believing the test has passed.
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A more straightforward way to handle asynchronous code is to use Promises:
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```js
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test('some test', done => {
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try {
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expect(false).toBe(true);
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done();
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} catch (e) {
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done(e);
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}
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test('the data is peanut butter', () => {
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return fetchData().then(data => {
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expect(data).toBe('peanut butter');
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});
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});
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```
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However, Jest supports a second way of having asynchronous tests - using
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promises.
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When a test or hook returns a promise, `jest` waits for that promise to resolve,
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as well as automatically failing should the promise reject.
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If your environment supports `async/await`, this becomes even simpler:
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```js
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test('some test', () => {
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return new Promise(done => {
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expect(false).toBe(true);
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done();
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});
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test('the data is peanut butter', async () => {
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const data = await fetchData();
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expect(data).toBe('peanut butter');
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});
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```
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Even though `done` is never called here, the Promise will still reject, and Jest
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will report the assertion error correctly.
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## Rule details
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This rule triggers a warning if you have a `done` callback in your test.
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This rule checks the function parameter of hooks & tests for use of the `done`
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argument, suggesting you return a promise instead.
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The following patterns are considered warnings:
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```js
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beforeEach(done => {
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// ...
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});
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test('myFunction()', done => {
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// ...
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});
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The following patterns are not considered warnings:
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```js
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beforeEach(async () => {
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await setupUsTheBomb();
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});
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test('myFunction()', () => {
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expect(myFunction()).toBeTruthy();
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});

‎src/rules/__tests__/no-done-callback.test.ts

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@@ -17,13 +17,18 @@ ruleTester.run('no-done-callback', rule, {
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'test("something", function() {})',
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'test("something", async function () {})',
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'test("something", someArg)',
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'beforeEach(() => {})',
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'beforeAll(async () => {})',
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'afterAll(() => {})',
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'afterAll(async function () {})',
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'afterAll(async function () {}, 5)',
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],
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invalid: [
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{
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code: 'test("something", (...args) => {args[0]();})',
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errors: [
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{
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messageId: 'illegalTestCallback',
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messageId: 'noDoneCallback',
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line: 1,
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column: 20,
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},
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code: 'test("something", done => {done();})',
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errors: [
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{
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messageId: 'illegalTestCallback',
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messageId: 'noDoneCallback',
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line: 1,
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column: 19,
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suggestions: [
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code: 'test("something", finished => {finished();})',
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errors: [
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{
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messageId: 'illegalTestCallback',
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messageId: 'noDoneCallback',
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line: 1,
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column: 19,
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suggestions: [
@@ -69,7 +74,7 @@ ruleTester.run('no-done-callback', rule, {
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code: 'test("something", (done) => {done();})',
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errors: [
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{
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messageId: 'illegalTestCallback',
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messageId: 'noDoneCallback',
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line: 1,
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column: 20,
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suggestions: [
@@ -87,7 +92,7 @@ ruleTester.run('no-done-callback', rule, {
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code: 'test("something", done => done())',
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errors: [
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{
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messageId: 'illegalTestCallback',
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messageId: 'noDoneCallback',
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line: 1,
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column: 19,
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suggestions: [
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code: 'test("something", (done) => done())',
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errors: [
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{
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messageId: 'illegalTestCallback',
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messageId: 'noDoneCallback',
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line: 1,
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column: 20,
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suggestions: [
@@ -121,7 +126,7 @@ ruleTester.run('no-done-callback', rule, {
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code: 'test("something", function(done) {done();})',
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errors: [
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{
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messageId: 'illegalTestCallback',
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messageId: 'noDoneCallback',
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line: 1,
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column: 28,
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suggestions: [
@@ -139,7 +144,7 @@ ruleTester.run('no-done-callback', rule, {
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code: 'test("something", function (done) {done();})',
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errors: [
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{
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messageId: 'illegalTestCallback',
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messageId: 'noDoneCallback',
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line: 1,
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column: 29,
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suggestions: [
@@ -183,7 +188,7 @@ ruleTester.run('no-done-callback', rule, {
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`,
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errors: [
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{
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messageId: 'illegalTestCallback',
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messageId: 'noDoneCallback',
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line: 1,
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column: 20,
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suggestions: [
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},
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],
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},
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{
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code: 'afterEach((...args) => {args[0]();})',
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errors: [
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{
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messageId: 'noDoneCallback',
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line: 1,
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column: 12,
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},
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],
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},
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{
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code: 'beforeAll(done => {done();})',
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errors: [
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{
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messageId: 'noDoneCallback',
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line: 1,
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column: 11,
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suggestions: [
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{
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messageId: 'suggestWrappingInPromise',
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data: { callback: 'done' },
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output:
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'beforeAll(() => {return new Promise(done => {done();})})',
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},
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],
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},
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],
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},
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{
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code: 'beforeAll(finished => {finished();})',
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errors: [
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{
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messageId: 'noDoneCallback',
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line: 1,
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column: 11,
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suggestions: [
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{
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messageId: 'suggestWrappingInPromise',
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data: { callback: 'finished' },
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output:
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'beforeAll(() => {return new Promise(finished => {finished();})})',
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},
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],
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},
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],
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},
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{
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code: 'beforeEach((done) => {done();})',
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errors: [
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{
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messageId: 'noDoneCallback',
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line: 1,
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column: 13,
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suggestions: [
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{
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messageId: 'suggestWrappingInPromise',
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data: { callback: 'done' },
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output:
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'beforeEach(() => {return new Promise((done) => {done();})})',
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},
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],
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},
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],
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},
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{
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code: 'afterAll(done => done())',
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errors: [
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{
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messageId: 'noDoneCallback',
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line: 1,
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column: 10,
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suggestions: [
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{
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messageId: 'suggestWrappingInPromise',
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data: { callback: 'done' },
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output: 'afterAll(() => new Promise(done => done()))',
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},
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],
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},
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],
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},
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{
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code: 'afterEach((done) => done())',
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errors: [
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{
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messageId: 'noDoneCallback',
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line: 1,
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column: 12,
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suggestions: [
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{
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messageId: 'suggestWrappingInPromise',
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data: { callback: 'done' },
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output: 'afterEach(() => new Promise((done) => done()))',
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},
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],
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},
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],
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},
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{
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code: 'beforeAll(function(done) {done();})',
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errors: [
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{
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messageId: 'noDoneCallback',
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line: 1,
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column: 20,
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suggestions: [
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{
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messageId: 'suggestWrappingInPromise',
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data: { callback: 'done' },
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output:
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'beforeAll(function() {return new Promise((done) => {done();})})',
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},
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],
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},
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],
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},
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{
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code: 'afterEach(function (done) {done();})',
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errors: [
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{
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messageId: 'noDoneCallback',
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line: 1,
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column: 21,
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suggestions: [
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{
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messageId: 'suggestWrappingInPromise',
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data: { callback: 'done' },
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output:
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'afterEach(function () {return new Promise((done) => {done();})})',
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},
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],
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},
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],
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},
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{
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code: 'beforeAll(async done => {done();})',
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errors: [{ messageId: 'useAwaitInsteadOfCallback', line: 1, column: 17 }],
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},
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{
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code: 'beforeAll(async done => done())',
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errors: [{ messageId: 'useAwaitInsteadOfCallback', line: 1, column: 17 }],
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},
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{
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code: 'beforeAll(async function (done) {done();})',
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errors: [{ messageId: 'useAwaitInsteadOfCallback', line: 1, column: 27 }],
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},
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{
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code: dedent`
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afterAll(async (done) => {
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await myAsyncTask();
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done();
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});
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`,
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errors: [{ messageId: 'useAwaitInsteadOfCallback', line: 1, column: 17 }],
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},
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{
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code: dedent`
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beforeEach((done) => {
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done();
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});
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`,
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errors: [
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{
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messageId: 'noDoneCallback',
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line: 1,
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column: 13,
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suggestions: [
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{
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messageId: 'suggestWrappingInPromise',
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data: { callback: 'done' },
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output: dedent`
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beforeEach(() => {return new Promise((done) => {
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done();
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})});
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`,
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},
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],
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},
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],
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},
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],
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});

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