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# Enforce assertion to be made in a test body (`expect-expect`)
Ensure that there is at least one `expect` call made in a test.
## Rule details
This rule triggers when there is no call made to `expect` in a test, to prevent users from forgetting to add assertions.
Examples of **incorrect** code for this rule:
```js it('should be a test', () => { console.log('no assertion'); }); test('should assert something', () => {}); ```
Examples of **correct** code for this rule:
```js it('should be a test', () => { expect(true).toBeDefined(); }); it('should work with callbacks/async', () => { somePromise().then(res => expect(res).toBe('passed')); }); ```
## Options
```json { "jest/expect-expect": [ "error", { "assertFunctionNames": ["expect"] } ] } ```
### `assertFunctionNames`
This array option specifies the names of functions that should be considered to be asserting functions. Function names can use wildcards i.e `request.*.expect`, `request.**.expect`, `request.*.expect*`
Examples of **incorrect** code for the `{ "assertFunctionNames": ["expect"] }` option:
```js /* eslint jest/expect-expect: ["error", { "assertFunctionNames": ["expect"] }] */
import { expectSaga } from 'redux-saga-test-plan'; import { addSaga } from '../src/sagas';
test('returns sum', () => { expectSaga(addSaga, 1, 1).returns(2).run(); }); ```
Examples of **correct** code for the `{ "assertFunctionNames": ["expect", "expectSaga"] }` option:
```js /* eslint jest/expect-expect: ["error", { "assertFunctionNames": ["expect", "expectSaga"] }] */
import { expectSaga } from 'redux-saga-test-plan'; import { addSaga } from '../src/sagas';
test('returns sum', () => { expectSaga(addSaga, 1, 1).returns(2).run(); }); ```
Since the string is compiled into a regular expression, you'll need to escape special characters such as `$` with a double backslash:
```js /* eslint jest/expect-expect: ["error", { "assertFunctionNames": ["expect\\$"] }] */
it('is money-like', () => { expect$(1.0); }); ```
Examples of **correct** code for working with the HTTP assertions library [SuperTest](https://www.npmjs.com/package/supertest) with the `{ "assertFunctionNames": ["expect", "request.*.expect"] }` option:
```js /* eslint jest/expect-expect: ["error", { "assertFunctionNames": ["expect", "request.*.expect"] }] */ const request = require('supertest'); const express = require('express');
const app = express();
describe('GET /user', function () { it('responds with json', function (done) { request(app).get('/user').expect('Content-Type', /json/).expect(200, done); }); }); ```
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