Add MatchesController and specs for it

app/controllers/matches_controller.rb

@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+class MatchesController < ApplicationController
+  # GET /matches/1
+  def show
+    render json: Match.find(params[:id]), include: ['scores.score', 'scores.team'], status: status
+  end
+
+  private
+
+  def match_params
+    ActiveModelSerializers::Deserialization.jsonapi_parse(params, only: [:state])
+  end
+end

config/routes.rb

@@ -2,4 +2,6 @@
 
 Rails.application.routes.draw do
   mount_devise_token_auth_for 'User', at: 'users'
+
+  resources :matches, only: %i[show]
 end

spec/controllers/matches_controller_spec.rb

@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe MatchesController, type: :controller do
+  let(:valid_attributes) do
+    skip('Add a hash of attributes valid for your model')
+  end
+
+  let(:invalid_attributes) do
+    skip('Add a hash of attributes invalid for your model')
+  end
+
+  let(:valid_session) { {} }
+
+  before do
+    @match = create(:match)
+    @match.scores = create_pair(:score)
+  end
+
+  describe 'GET #show' do
+    it 'should return success' do
+      get :show, params: { id: @match.to_param }
+      expect(response).to be_successful
+      expect(response.content_type).to eq('application/json')
+    end
+
+    it 'should return the correct state' do
+      get :show, params: { id: @match.to_param }
+      body = ActiveModelSerializers::Deserialization.jsonapi_parse(JSON.parse(response.body))
+      expect(body[:state]).to be(@match.state)
+      expect(body[:score_ids]).to eq(@match.scores.map { |score| score.id.to_s })
+    end
+  end
+end

spec/routing/matches_routing_spec.rb

@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe MatchesController, type: :routing do
+  describe 'routing' do
+    it 'routes to #show' do
+      expect(get: '/matches/1').to route_to('matches#show', id: '1')
+    end
+  end
+end