100 lines
2.0 KiB
Markdown
100 lines
2.0 KiB
Markdown
# Suggest using `expect.assertions()` OR `expect.hasAssertions()` (`prefer-expect-assertions`)
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Ensure every test to have either `expect.assertions(<number of assertions>)` OR
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`expect.hasAssertions()` as its first expression.
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## Rule details
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This rule triggers a warning if,
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- `expect.assertions(<number of assertions>)` OR `expect.hasAssertions()` is not
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present as first statement in a test, e.g.:
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```js
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test('my test', () => {
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expect(someThing()).toEqual('foo');
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});
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```
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- `expect.assertions(<number of assertions>)` is the first statement in a test
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where argument passed to `expect.assertions(<number of assertions>)` is not a
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valid number, e.g.:
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```js
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test('my test', () => {
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expect.assertions('1');
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expect(someThing()).toEqual('foo');
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});
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```
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### Default configuration
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The following patterns are considered warnings:
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```js
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test('my test', () => {
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expect.assertions('1');
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expect(someThing()).toEqual('foo');
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});
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test('my test', () => {
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expect(someThing()).toEqual('foo');
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});
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```
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The following patterns would not be considered warnings:
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```js
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test('my test', () => {
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expect.assertions(1);
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expect(someThing()).toEqual('foo');
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});
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test('my test', () => {
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expect.hasAssertions();
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expect(someThing()).toEqual('foo');
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});
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```
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## Options
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#### `onlyFunctionsWithAsyncKeyword`
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When `true`, this rule will only warn for tests that use the `async` keyword.
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```json
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{
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"rules": {
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"jest/prefer-expect-assertions": [
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"warn",
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{ "onlyFunctionsWithAsyncKeyword": true }
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]
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}
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}
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```
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When `onlyFunctionsWithAsyncKeyword` option is set to `true`, the following
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pattern would be a warning:
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```js
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test('my test', async () => {
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const result = await someAsyncFunc();
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expect(result).toBe('foo');
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});
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```
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While the following patterns would not be considered warnings:
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```js
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test('my test', () => {
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const result = someFunction();
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expect(result).toBe('foo');
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});
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test('my test', async () => {
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expect.assertions(1);
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const result = await someAsyncFunc();
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expect(result).toBe('foo');
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});
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```
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