raise error for role API requests with nonexistent sections

app/controllers/api/roles_controller.rb

@@ -115,14 +115,20 @@ def create_role
       ApplicationRecord.transaction do
         user = User.find_by(user_name: params[:user_name])
         role = Role.new(**role_params, user: user, course: @current_course)
-        role.section = @current_course.sections.find_by(name: params[:section_name]) if params[:section_name]
+        if params[:section_name]
+          if params[:section_name].empty?
+            role.section = nil
+          else
+            role.section = @current_course.sections.find_by!(name: params[:section_name])
+          end
+        end
         role.grace_credits = params[:grace_credits] if params[:grace_credits]
         role.hidden = params[:hidden].to_s.casecmp('true').zero? if params[:hidden]
         role.save!
         render 'shared/http_status', locals: { code: '201', message:
             HttpStatusHelper::ERROR_CODE['message']['201'] }, status: :created
       end
-    rescue ActiveRecord::SubclassNotFound, ActiveRecord::RecordInvalid => e
+    rescue ActiveRecord::SubclassNotFound, ActiveRecord::RecordInvalid, ActiveRecord::RecordNotFound => e
       render 'shared/http_status', locals: { code: '422', message: e.to_s }, status: :unprocessable_entity
     rescue StandardError
       render 'shared/http_status', locals: { code: '500', message:
@@ -131,14 +137,20 @@ def create_role
 
     def update_role(role)
       ApplicationRecord.transaction do
-        role.section = @current_course.sections.find_by(name: params[:section_name]) if params[:section_name]
+        if params[:section_name]
+          if params[:section_name].empty?
+            role.section = nil
+          else
+            role.section = @current_course.sections.find_by!(name: params[:section_name])
+          end
+        end
         role.grace_credits = params[:grace_credits] if params[:grace_credits]
         role.hidden = params[:hidden].to_s.casecmp('true').zero? if params[:hidden]
         role.save!
       end
       render 'shared/http_status', locals: { code: '200', message:
           HttpStatusHelper::ERROR_CODE['message']['200'] }, status: :ok
-    rescue ActiveRecord::SubclassNotFound, ActiveRecord::RecordInvalid => e
+    rescue ActiveRecord::SubclassNotFound, ActiveRecord::RecordInvalid, ActiveRecord::RecordNotFound => e
       render 'shared/http_status', locals: { code: '422', message: e.to_s }, status: :unprocessable_entity
     rescue StandardError
       render 'shared/http_status', locals: { code: '500', message:

spec/controllers/api/roles_controller_spec.rb

@@ -187,6 +187,22 @@
             expect(response).to have_http_status(422)
           end
         end
+        context 'with an invalid section name' do
+          let(:other_params) { { section_name: 'section.name' } }
+          it 'should raise a 422 error' do
+            expect(response).to have_http_status(422)
+          end
+        end
+        context 'with a nil section name' do
+          let(:created_student) { Student.joins(:user).where('users.user_name': student.user_name).first }
+          let(:other_params) { { section_name: nil } }
+          it 'should be successful' do
+            expect(response).to have_http_status(201)
+          end
+          it 'should not set a section' do
+            expect(created_student.section).to be_nil
+          end
+        end
       end
     end
 
@@ -240,6 +256,27 @@
           student.reload
           expect(student.hidden).to eq(true)
         end
+        context 'with an invalid section name' do
+          it 'should raise a 422 error' do
+            put :update, params: { id: student.id, course_id: course.id, section_name: 'section.name' }
+            expect(response).to have_http_status(422)
+          end
+        end
+        context 'with a nil section name' do
+          let(:section) { create :section }
+          before :each do
+            student.update!(section: section)
+          end
+          it 'should be successful' do
+            put :update, params: { id: student.id, course_id: course.id, section_name: nil }
+            expect(response).to have_http_status(200)
+          end
+          it 'should set the section to nil' do
+            put :update, params: { id: student.id, course_id: course.id, section_name: nil }
+            student.reload
+            expect(student.section).to be_nil
+          end
+        end
       end
 
       context 'when updating a user that does not exist' do