mirror of
https://github.com/JamesIves/github-pages-deploy-action.git
synced 2023-12-15 20:03:39 +08:00
77 lines
1.5 KiB
Markdown
77 lines
1.5 KiB
Markdown
# Avoid using a callback in asynchronous tests (no-test-callback)
|
|
|
|
Jest allows you to pass a callback to test definitions, typically called `done`,
|
|
that is later invoked to indicate that the asynchronous test is complete.
|
|
|
|
However, that means that if your test throws (e.g. because of a failing
|
|
assertion), `done` will never be called unless you manually use `try-catch`.
|
|
|
|
```js
|
|
test('some test', done => {
|
|
expect(false).toBe(true);
|
|
done();
|
|
});
|
|
```
|
|
|
|
The test above will time out instead of failing the assertions, since `done` is
|
|
never called.
|
|
|
|
Correct way of doing the same thing is to wrap it in `try-catch`.
|
|
|
|
```js
|
|
test('some test', done => {
|
|
try {
|
|
expect(false).toBe(true);
|
|
done();
|
|
} catch (e) {
|
|
done(e);
|
|
}
|
|
});
|
|
```
|
|
|
|
However, Jest supports a second way of having asynchronous tests - using
|
|
promises.
|
|
|
|
```js
|
|
test('some test', () => {
|
|
return new Promise(done => {
|
|
expect(false).toBe(true);
|
|
done();
|
|
});
|
|
});
|
|
```
|
|
|
|
Even though `done` is never called here, the Promise will still reject, and Jest
|
|
will report the assertion error correctly.
|
|
|
|
## Rule details
|
|
|
|
This rule triggers a warning if you have a `done` callback in your test.
|
|
|
|
The following patterns are considered warnings:
|
|
|
|
```js
|
|
test('myFunction()', done => {
|
|
// ...
|
|
});
|
|
|
|
test('myFunction()', function(done) {
|
|
// ...
|
|
});
|
|
```
|
|
|
|
The following patterns are not considered warnings:
|
|
|
|
```js
|
|
test('myFunction()', () => {
|
|
expect(myFunction()).toBeTruthy();
|
|
});
|
|
|
|
test('myFunction()', () => {
|
|
return new Promise(done => {
|
|
expect(myFunction()).toBeTruthy();
|
|
done();
|
|
});
|
|
});
|
|
```
|