Test returning unprocessable entity response

We now test sending a senseless state and also what happens when the
match.update method fails for some reason.

spec/controllers/matches_controller_spec.rb

@@ -27,6 +27,7 @@ RSpec.describe MatchesController, type: :controller do
   end
 
   describe 'POST #update' do
+    context 'on a running playoff match' do
       let(:valid_update) do
         {
           state: 'in_progress'
@@ -39,6 +40,12 @@ RSpec.describe MatchesController, type: :controller do
         }
       end
 
+      let(:senseless_update) do
+        {
+          state: 'not_ready'
+        }
+      end
+
       context 'as owner' do
         before(:each) do
           apply_authentication_headers_for @match.owner
@@ -70,6 +77,7 @@ RSpec.describe MatchesController, type: :controller do
               apply_authentication_headers_for @running_playoff_match.owner
             end
 
+            context 'match update succeeds' do
               context 'on a decided match' do
                 before do
                   @running_playoff_match.match_scores.each_with_index do |ms, i|
@@ -136,6 +144,20 @@ RSpec.describe MatchesController, type: :controller do
                 end
               end
             end
+
+            context 'match update fails' do
+              before do
+                allow_any_instance_of(Match)
+                  .to receive(:update)
+                  .and_return(false)
+              end
+
+              it 'returns unprocessable entity' do
+                put :update, params: { id: @running_playoff_match.to_param }.merge(finished)
+                expect(response).to have_http_status(:unprocessable_entity)
+              end
+            end
+          end
         end
 
         context 'with invalid params' do
@@ -144,6 +166,13 @@ RSpec.describe MatchesController, type: :controller do
             expect(response).to have_http_status(:unprocessable_entity)
           end
         end
+
+        context 'with senseless params' do
+          it 'renders an unprocessable entity response' do
+            put :update, params: { id: @match.to_param }.merge(senseless_update)
+            expect(response).to have_http_status(:unprocessable_entity)
+          end
+        end
       end
 
       context 'as another user' do
@@ -160,3 +189,4 @@ RSpec.describe MatchesController, type: :controller do
       end
     end
   end
+end