Prevent matches from being stopped without a winner in playoffs

app/controllers/matches_controller.rb

@@ -13,6 +13,11 @@ class MatchesController < ApplicationController
   # PATCH/PUT /matches/1
   def update
     new_state = match_params['state']
+    if new_state == 'finished' && @match.current_leading_team.nil?
+      render json: { error: 'Stopping undecided Matches isn\'t allowed in playoff stage' },
+             status: :unprocessable_entity
+      return
+    end
     if @match.update(match_params)
       if new_state == 'finished'
         result = PopulateMatchBelowAndSave.call(match: @match) unless @match.group_match?

spec/controllers/matches_controller_spec.rb

@@ -70,6 +70,7 @@ RSpec.describe MatchesController, type: :controller do
             apply_authentication_headers_for @running_playoff_match.owner
           end
 
+          context 'on a decided match' do
             before do
               @running_playoff_match.match_scores.each_with_index do |ms, i|
                 ms.points = i
@@ -100,6 +101,38 @@ RSpec.describe MatchesController, type: :controller do
               end
             end
           end
+
+          context 'on a undecided match' do
+            before do
+              @running_playoff_match.match_scores.each do |ms|
+                ms.points = 42
+                ms.save!
+              end
+              put :update, params: { id: @running_playoff_match.to_param }.merge(finished)
+              @running_playoff_match.reload
+            end
+
+            it 'returns unprocessable entity' do
+              expect(response).to have_http_status(:unprocessable_entity)
+              expect(@running_playoff_match.state).to eq('in_progress')
+            end
+
+            describe 'doesn\'t update the match below' do
+              before do
+                @match_below = @tournament.stages.find_by(level: @amount_of_stages - 1).matches
+                                          .find_by(position: @running_playoff_match.position / 2).reload
+              end
+
+              it 'teams' do
+                expect(@match_below.teams.empty?).to be(true)
+              end
+
+              it 'status' do
+                expect(@match_below.state).to eq('not_ready')
+              end
+            end
+          end
+        end
       end
 
       context 'with invalid params' do