github-pages-deploy-action/node_modules/eslint-plugin-jest/docs/rules/no-try-expect.md
2020-03-06 22:45:40 -05:00

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# Prevent catch assertions in tests (no-try-expect)
This rule prevents the use of `expect` inside `catch` blocks.
## Rule Details
Expectations inside a `catch` block can be silently skipped. While Jest provides
an `expect.assertions(number)` helper, it might be cumbersome to add this to
every single test. Using `toThrow` concisely guarantees that an exception was
thrown, and that its contents match expectations.
The following patterns are warnings:
```js
it('foo', () => {
try {
foo(); // `foo` may be refactored to not throw exceptions, yet still appears to be tested here.
} catch (err) {
expect(err).toMatch(/foo error/);
}
});
it('bar', async () => {
try {
await foo();
} catch (err) {
expect(err).toMatch(/foo error/);
}
});
it('baz', async () => {
try {
await foo();
} catch (err) {
expect(err).toMatchObject({ code: 'MODULE_NOT_FOUND' });
}
});
```
The following patterns are not warnings:
```js
it('foo', () => {
expect(() => foo()).toThrow(/foo error/);
});
it('bar', async () => {
await expect(fooPromise).rejects.toThrow(/foo error/);
});
it('baz', async () => {
await expect(() => foo()).rejects.toThrow(
expect.objectContaining({ code: 'MODULE_NOT_FOUND' }),
);
});
```