Implement GroupsController

app/controllers/groups_controller.rb

@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+class GroupsController < ApplicationController
+  before_action :set_group, only: %i[show]
+
+  # GET /groups/1
+  def show
+    render json: @group, include: '**'
+  end
+
+  private
+
+  def set_group
+    @group = Group.find(params[:id])
+  end
+end

config/routes.rb

@@ -12,4 +12,5 @@ Rails.application.routes.draw do
     resources :statistics, only: %i[index]
   end
   resources :match_scores, only: %i[show update]
+  resources :groups, only: %i[show]
 end

spec/controllers/groups_controller_spec.rb

@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe GroupsController, type: :controller do
+  before do
+    @group = create(:group)
+  end
+
+  describe 'GET #show' do
+    it 'returns a success response' do
+      get :show, params: { id: @group.to_param }
+      expect(response).to be_successful
+    end
+
+    it 'should return the correct group' do
+      get :show, params: { id: @group.to_param }
+      body = deserialize_response response
+      expect(Group.find_by(id: body[:id])).to eq(@group)
+      expect(body[:number]).to eq(@group.number)
+      expect(body[:matches].size).to eq(@group.matches.size)
+      expect(body[:group_scores].size).to eq(@group.group_scores.size)
+    end
+  end
+end