fix(nbp): specify JSON as a default format for relationship_status

This change is necessary to get proper error messages in case of (unhandled) exceptions. Previously, a `Pundit::NotAuthorizedError` would redirect to an HTML page. Now, such an exception with simply return a JSON with the proper status code of 401.

Since we are using `fetch` with a path not containing any specific format, the previously used default would log `syntax error` messages in the JavaScript console (due to the followed redirect and the attempt to parse the then-received HTML as JSON).

Author: MrSerth

config/routes.rb

@@ -36,7 +36,7 @@
     collection do
       get '/nbp_wallet/connect', to: 'users/nbp_wallet#connect'
       get '/nbp_wallet/qr_code', to: 'users/nbp_wallet#qr_code'
-      get '/nbp_wallet/relationship_status', to: 'users/nbp_wallet#relationship_status'
+      get '/nbp_wallet/relationship_status', to: 'users/nbp_wallet#relationship_status', defaults: {format: :json}
       get '/nbp_wallet/finalize', to: 'users/nbp_wallet#finalize'
     end
   end

spec/requests/users/nbp_wallet/relationship_status_spec.rb

@@ -12,6 +12,15 @@
     set_session(session_params)
   end
 
+  shared_examples 'an unauthorized JSON request' do
+    expect_json
+    expect_http_status(:unauthorized)
+
+    it 'returns a JSON with the error message' do
+      expect(response.parsed_body['error']).to eq I18n.t('common.errors.not_authorized')
+    end
+  end
+
   context 'without errors' do
     context 'with a Relationship' do
       before { allow(Enmeshed::Relationship).to receive(:pending_for).with(uid).and_return(Enmeshed::Relationship) }
@@ -45,7 +54,7 @@
         relationship_status_request
       end
 
-      it_behaves_like 'an unauthorized request'
+      it_behaves_like 'an unauthorized JSON request'
     end
 
     context 'with a session for a completed user' do
@@ -54,7 +63,7 @@
         relationship_status_request
       end
 
-      it_behaves_like 'an unauthorized request'
+      it_behaves_like 'an unauthorized JSON request'
     end
 
     context 'when the connector is down' do