React-testing-library: toHaveAttribute custom matcher

[gnapse]

I'm finding my self commonly checking if an element has a given attribute or not, and possibly also expecting a certain value off some attribute.

expect(getByTestId('ok-button').hasAttribute('disabled')).toBeTruthy()
expect(getByTestId('dropdown-toggle').getAttribute('aria-expanded')).toEqual('false')

I wonder if it would be acceptable to the goals and intentions of this library to provide certain other custom matchers for common tasks. In this particular case I'd be proposing a .toHaveAttribute custom matcher that could work both to assert that an element has an attribute present or not, but also to assert that the attribute is present and has a certain value:

expect(getByTestId('ok-button')).toHaveAttribute('disabled')
expect(getByTestId('dropdown-toggle')).toHaveAttribute('aria-expanded', 'false')

It could be considered syntactic sugar, but I think it makes tests more readable. Although I'd also understand if these are considered out of the scope of this library.

[kentcdodds]

Yes! This would be super :+1: Thanks for the idea! Would you like to contribute to make it?

[gnapse]

I'd love to. I'm on it!