cities_spec.rb

  it "returns a list of available cities" do
    create(:city, name: "Boston")

    get_index

    expect(json_body).to eq({ cities: %w(Boston) })
  end

  def get_index
    get "/api/cities", {}.to_json, default_headers.merge("HTTP_AUTHORIZATION" => token_header_value, "Authorization" => token_header_value)
  end

  def token_header_value
    ActionController::HttpAuthentication::Token.encode_credentials(token)
  end

  def token
    create(:user).token
  end