RSpec.configure do |config|
  # ...

  config.prepend(
    Module.new do
      %i[get post patch put delete head].each do |method|
        params_snippet = method.in?(%i[post patch put]) ? "args[:params] = args[:params].to_json" : ""
        module_eval <<~RUBY, __FILE__, __LINE__ + 1
          def #{method}(path, **args)
            if args.present? && args.values.none? { |v| v.is_a?(Rack::Test::UploadedFile) }
              #{params_snippet}
              args[:headers] = (args[:headers] || {}).merge("CONTENT_TYPE" => "application/json")
            end
            super(path, **args)
          end
        RUBY
      end
    end,
    type: :request,
  )

  # ...
end