RSpec have_attributes example

api_spec.rb

# API
class FakeResponse < Struct.new(:status, :code)
  def success?
    code == 200
  end
end

class FakeAPI
  def call
    FakeResponse.new('Success', 200)    
  end
end

# Test
RSpec.describe FakeAPI do
  subject(:api) { FakeAPI.new }
  
  describe '#call' do
    subject { api.call }
    
    it { is_expected.to be_success }
    it { is_expected.to have_attributes(status: match(/Success/)) }
    it { is_expected.to have_attributes(code: 200) }
  end
end

# Generated `--format document`
# FakeAPI
#  #call
#    is expected to be success
#    is expected to have attributes {status: match(/Success/)}
#    is expected to have attributes {code: 200 }

To test a "nested" result, use describe but not suggested more than 3 levels.

RSpec.describe FakeAPI do
  subject(:api) { FakeAPI.new }
  
  describe '#call' do
    subject(:response) { api.call }
    
    it { is_expected.to be_success }
    it { is_expected.to have_attributes(status: match(/Success/)) }
    it { is_expected.to have_attributes(code: 200) }

    describe "#headers" do
      subject(:headers) { response.headers }

      it { is_expected.to include({ 'Content-Type' => 'application/json' }) }
    end
  end
end