Rails success? predicate deprecation

I've been running a new Rails project up on the master branch while having a play with the new ActiveStorage module to see if it will be a good fit. Running the test suite this morning though I found that the RSpec output was littered with these deprecation warnings:

The success? predicate is deprecated and will be removed in Rails 6.0. Please use successful? as provided by Rack::Response::Helpers.

It turns out that my use of expect(response).to have_http_status :success is now the old way of doing things. While the error message wasn't particularly clear as to what to do, I worked it out. Here are some of the ways you can update your code and remove the deprecation warning.

# Call the predicate yourself
expect(response).to be successful?

# Use RSpec magic matching
expect(response).to be_successful