github-pages-deploy-action/node_modules/eslint-plugin-jest/docs/rules/expect-expect.md
2020-03-06 22:45:40 -05:00

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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 whitelists the assertion function names to look for.
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();
);
```