Refactor LTI parameters and add study group

* This change also requires that submissions in our test need to have a valid study group.

spec/concerns/lti_spec.rb

@@ -108,7 +108,7 @@ describe Lti do
     let(:submission) { create(:submission) }
 
     before do
-      create(:lti_parameter, consumers_id: consumer.id, external_users_id: submission.contributor_id, exercises_id: submission.exercise_id)
+      create(:lti_parameter, external_user: submission.contributor, exercise: submission.exercise)
     end
 
     context 'with an invalid score' do
@@ -173,15 +173,15 @@ describe Lti do
       controller.instance_variable_set(:@current_user, create(:external_user))
       controller.instance_variable_set(:@exercise, create(:fibonacci))
       expect(controller.session).to receive(:[]=).with(:external_user_id, anything)
-      controller.send(:store_lti_session_data, consumer: build(:consumer), parameters:)
+      controller.send(:store_lti_session_data, parameters)
     end
 
     it 'creates an LtiParameter Object' do
-      before_count = LtiParameter.count
-      controller.instance_variable_set(:@current_user, create(:external_user))
-      controller.instance_variable_set(:@exercise, create(:fibonacci))
-      controller.send(:store_lti_session_data, consumer: build(:consumer), parameters:)
-      expect(LtiParameter.count).to eq(before_count + 1)
+      expect do
+        controller.instance_variable_set(:@current_user, create(:external_user))
+        controller.instance_variable_set(:@exercise, create(:fibonacci))
+        controller.send(:store_lti_session_data, parameters)
+      end.to change(LtiParameter, :count).by(1)
     end
   end
 

spec/controllers/sessions_controller_spec.rb

@@ -101,7 +101,6 @@ describe SessionsController do
       end
 
       it 'stores LTI parameters in the session' do
-        # Todo replace session with lti_parameter /should be done already
         expect(controller).to receive(:store_lti_session_data)
         perform_request
       end
@@ -191,7 +190,6 @@ describe SessionsController do
       end
 
       it 'clears the session' do
-        # Todo replace session with lti_parameter /should be done already
         expect(controller).to receive(:clear_lti_session_data)
         delete :destroy
       end
@@ -207,15 +205,12 @@ describe SessionsController do
     let(:submission) { create(:submission, exercise: create(:dummy)) }
 
     before do
-      # Todo replace session with lti_parameter
-      # Todo create LtiParameter Object
-      # session[:lti_parameters] = {}
+      create(:lti_parameter, external_user: submission.contributor)
       allow(controller).to receive(:current_user).and_return(submission.contributor)
       perform_request.call
     end
 
     it 'clears the session' do
-      # Todo replace session with lti_parameter /should be done already
       expect(controller).to receive(:clear_lti_session_data)
       perform_request.call
     end

spec/factories/lti_parameter.rb

@@ -8,12 +8,18 @@ FactoryBot.define do
   }.freeze
 
   factory :lti_parameter do
-    consumer
     exercise factory: :math
     external_user
 
     lti_parameters { lti_params }
 
+    after(:create) do |lti_parameter|
+      # Do not change anything if a study group was provided explicitly or user has no study groups
+      next if lti_parameter.study_group.present? || lti_parameter.external_user.study_groups.blank?
+
+      lti_parameter.update!(study_group: lti_parameter.external_user.study_groups.first)
+    end
+
     trait :without_outcome_service_url do
       lti_parameters { lti_params.except(:lis_outcome_service_url) }
     end