expect-expect)Ensure that there is at least one expect call made in a test.
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'));
});
json
{
"jest/expect-expect": [
"error",
{
"assertFunctionNames": ["expect"],
"additionalTestBlockFunctions": []
}
]
}
assertFunctionNamesThis 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 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); }); }); ```
additionalTestBlockFunctionsThis array can be used to specify the names of functions that should also be treated as test blocks:
json
{
"rules": {
"jest/expect-expect": [
"error",
{ "additionalTestBlockFunctions": ["theoretically"] }
]
}
}
The following is correct when using the above configuration:
```js import theoretically from 'jest-theories';
describe('NumberToLongString', () => { const theories = [ { input: 100, expected: 'One hundred' }, { input: 1000, expected: 'One thousand' }, { input: 10000, expected: 'Ten thousand' }, { input: 100000, expected: 'One hundred thousand' }, ];
theoretically( 'the number {input} is correctly translated to string', theories, theory => { const output = NumberToLongString(theory.input); expect(output).toBe(theory.expected); }, ); }); ```