api_request_helper.rb

# Gemfile
# gem "bootic_client"
# group :test do
#  gem "rack-test"
# end

# spec/support/api_request_helper.rb
# Usage in your API tests
# it "loads the root resource" do
#  authorize!(user_id: 1)
#
#  expect(root.title).to eq "Hi!"
# end
#
# it "follows links" do
#  users = root.users
#
#  expect(users.total_items).to eq 2
#  expect(users.map(&:name)).to eq ["jane", "joe"]
# end

module ApiRequestHelper
  # this is your Rack app
  def app
    MyApplication
  end
  
  def authorize!(claims)
    @access_token = generate_a_token_somehow(claims)
  end

  require "bootic_client"
  BooticClient.configure do |c|
    c.api_root = "http://example.org"
  end

  def client
    @client ||= BooticClient.client(
      :bearer,
      access_token: @access_token,
      faraday_adapter: [:rack, app]
    )
  end

  def root
    @root ||= client.root
  end
end

I'm using the "bearer token" strategy for the client, but you can use any or no auth strategy depending on your API.