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

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# Enforce valid `expect()` usage (valid-expect)
Ensure `expect()` is called with a single argument and there is an actual
expectation made.
## Rule details
This rule triggers a warning if `expect()` is called with more than one argument
or without arguments. It would also issue a warning if there is nothing called
on `expect()`, e.g.:
```js
expect();
expect('something');
```
or when a matcher function was not called, e.g.:
```js
expect(true).toBeDefined;
```
or when an async assertion was not `await`ed or returned, e.g.:
```js
expect(Promise.resolve('Hi!')).resolves.toBe('Hi!');
```
This rule is enabled by default.
## Options
```js
{
type: 'object',
properties: {
alwaysAwait: {
type: 'boolean',
default: false,
},
},
additionalProperties: false,
}
```
### `alwaysAwait`
Enforces to use `await` inside block statements. Using `return` will trigger a
warning. Returning one line statements with arrow functions is _always allowed_.
Examples of **incorrect** code for the { "alwaysAwait": **true** } option:
```js
// alwaysAwait: true
test('test1', async () => {
await expect(Promise.resolve(2)).resolves.toBeDefined();
return expect(Promise.resolve(1)).resolves.toBe(1); // `return` statement will trigger a warning
});
```
Examples of **correct** code for the { "alwaysAwait": **true** } option:
```js
// alwaysAwait: true
test('test1', async () => {
await expect(Promise.resolve(2)).resolves.toBeDefined();
await expect(Promise.resolve(1)).resolves.toBe(1);
});
test('test2', () => expect(Promise.resolve(2)).resolves.toBe(2));
```
### Default configuration
The following patterns are considered warnings:
```js
expect();
expect().toEqual('something');
expect('something', 'else');
expect('something');
expect(true).toBeDefined;
expect(Promise.resolve('hello')).resolves;
expect(Promise.resolve('hello')).resolves.toEqual('hello');
Promise.resolve(expect(Promise.resolve('hello')).resolves.toEqual('hello'));
Promise.all([
expect(Promise.resolve('hello')).resolves.toEqual('hello'),
expect(Promise.resolve('hi')).resolves.toEqual('hi'),
]);
```
The following patterns are not warnings:
```js
expect('something').toEqual('something');
expect([1, 2, 3]).toEqual([1, 2, 3]);
expect(true).toBeDefined();
await expect(Promise.resolve('hello')).resolves.toEqual('hello');
await Promise.resolve(
expect(Promise.resolve('hello')).resolves.toEqual('hello'),
);
await Promise.all(
expect(Promise.resolve('hello')).resolves.toEqual('hello'),
expect(Promise.resolve('hi')).resolves.toEqual('hi'),
);
```