diff --git a/.active_record_doctor.rb b/.active_record_doctor.rb
new file mode 100644
index 0000000000..d113267c7e
--- /dev/null
+++ b/.active_record_doctor.rb
@@ -0,0 +1,10 @@
+ActiveRecordDoctor.configure do
+  # api_key and schema are NOT NULL but are populated by AutotestSetting's
+  # before_create callback (register_autotester), which runs after validation.
+  # A presence validator can never pass on create, so these are exempt.
+  detector :missing_presence_validation,
+           ignore_attributes: [
+             'AutotestSetting.api_key',
+             'AutotestSetting.schema'
+           ]
+end
diff --git a/Changelog.md b/Changelog.md
index 5a725700d4..26a0f7535d 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -30,6 +30,7 @@
 - Fixed `(hidden)` assignment labeling for assignments with `visible_on` and/or `visible_until` set (#7944)
 
 ### 🔧 Internal changes
+- Added `NOT NULL` constraints and presence/inclusion validators flagged by `active_record_doctor` checks `missing_non_null_constraint` and `missing_presence_validation`
 - Added tests for `MarksGradersController` to achieve full test coverage for `randomly_assign` (#7947)
 - Refactored `AuthenticationHelper#sign_in` to set session values directly instead of going through `MainController#login` (#7962)
 - Updated `MainController` specs to dispatch `post :login` directly in tests that assert on login's response, instead of relying on `sign_in`'s internal request (#7962)
diff --git a/app/jobs/split_pdf_job.rb b/app/jobs/split_pdf_job.rb
index b0771fd060..6cfceea0c8 100644
--- a/app/jobs/split_pdf_job.rb
+++ b/app/jobs/split_pdf_job.rb
@@ -145,6 +145,7 @@ def perform(exam_template, _path, split_pdf_log, _original_filename = nil, _role
           m_logger.log(status)
           split_page_updates << {
             id: split_page_id,
+            split_pdf_log_id: split_pdf_log.id,
             status: status,
             group_id: nil,
             exam_page_number: nil
@@ -156,6 +157,7 @@ def perform(exam_template, _path, split_pdf_log, _original_filename = nil, _role
           m_logger.log(status)
           split_page_updates << {
             id: split_page_id,
+            split_pdf_log_id: split_pdf_log.id,
             status: status,
             group_id: nil,
             exam_page_number: nil
@@ -166,6 +168,7 @@ def perform(exam_template, _path, split_pdf_log, _original_filename = nil, _role
           m_logger.log("#{m[:short_id]}: exam number #{m[:exam_num]}, page #{m[:page_num]}")
           split_page_updates << {
             id: split_page_id,
+            split_pdf_log_id: split_pdf_log.id,
             status: status,
             group_id: group_id,
             exam_page_number: m[:page_num].to_i
@@ -173,7 +176,7 @@ def perform(exam_template, _path, split_pdf_log, _original_filename = nil, _role
         end
       end
       SplitPage.upsert_all(split_page_updates, returning: false)
-      num_complete = save_pages(exam_template, partial_exams, on_duplicate)
+      num_complete = save_pages(exam_template, partial_exams, split_pdf_log, on_duplicate)
       num_incomplete = partial_exams.length - num_complete
 
       split_pdf_log.update(
@@ -210,7 +213,7 @@ def perform(exam_template, _path, split_pdf_log, _original_filename = nil, _role
   end
 
   # Save the pages into groups for this assignment
-  def save_pages(exam_template, partial_exams, on_duplicate = nil)
+  def save_pages(exam_template, partial_exams, split_pdf_log, on_duplicate = nil)
     complete_dir = File.join(exam_template.base_path, 'complete')
     incomplete_dir = File.join(exam_template.base_path, 'incomplete')
     error_dir = File.join(exam_template.base_path, 'error')
@@ -258,7 +261,7 @@ def save_pages(exam_template, partial_exams, on_duplicate = nil)
           status = "ERROR: #{exam_template.name}: exam number #{exam_num}, page #{page_num} already exists"
         end
         # update status of page
-        split_page_updates << { id: split_page_id, status: status }
+        split_page_updates << { id: split_page_id, split_pdf_log_id: split_pdf_log.id, status: status }
       end
       SplitPage.upsert_all(split_page_updates, returning: false)
 
diff --git a/app/models/annotation.rb b/app/models/annotation.rb
index 4ea95528bb..e12bb25c71 100644
--- a/app/models/annotation.rb
+++ b/app/models/annotation.rb
@@ -40,7 +40,7 @@
 class Annotation < ApplicationRecord
   belongs_to :submission_file
   belongs_to :annotation_text
-  belongs_to :creator, polymorphic: true
+  belongs_to :creator, polymorphic: true, optional: true
   belongs_to :result
 
   has_one :course, through: :submission_file
diff --git a/app/models/annotation_text.rb b/app/models/annotation_text.rb
index 743bd194f0..01414a8793 100644
--- a/app/models/annotation_text.rb
+++ b/app/models/annotation_text.rb
@@ -22,7 +22,7 @@
 #
 # rubocop:enable Layout/LineLength, Lint/RedundantCopDisableDirective
 class AnnotationText < ApplicationRecord
-  belongs_to :creator, class_name: 'Role'
+  belongs_to :creator, class_name: 'Role', optional: true
   belongs_to :last_editor, class_name: 'Role', optional: true
 
   has_one :course, through: :creator
diff --git a/app/models/assessment.rb b/app/models/assessment.rb
index d905b4af76..39af336166 100644
--- a/app/models/assessment.rb
+++ b/app/models/assessment.rb
@@ -65,6 +65,9 @@ class Assessment < ApplicationRecord
   validate :visible_dates_are_valid
   validates :description, presence: true
   validates :is_hidden, inclusion: { in: [true, false] }
+  validates :show_total, inclusion: { in: [true, false] }
+  validates :type, presence: true
+  validates :message, exclusion: { in: [nil] }
   validates :short_identifier, format: { with: /\A[a-zA-Z0-9\-_]+\z/ }
 
   def self.type
diff --git a/app/models/assignment.rb b/app/models/assignment.rb
index cb420174e9..46f7d5e4b6 100644
--- a/app/models/assignment.rb
+++ b/app/models/assignment.rb
@@ -419,7 +419,7 @@ def all_grouping_data
 
   def add_group(new_group_name = nil)
     if group_name_autogenerated
-      group = self.course.groups.new
+      group = self.course.groups.new(group_name: SecureRandom.uuid)
       group.save(validate: false)
       group.group_name = group.get_autogenerated_group_name
       group.save
@@ -447,7 +447,7 @@ def add_group_api(new_group_name = nil, members = [])
             g.repo_name = student_user_name
           end
         elsif group_name_autogenerated
-          group = course.groups.new
+          group = course.groups.new(group_name: SecureRandom.uuid)
           group.save(validate: false)
           group.group_name = group.get_autogenerated_group_name
         else
diff --git a/app/models/assignment_properties.rb b/app/models/assignment_properties.rb
index f1e31dbd97..bd30658f33 100644
--- a/app/models/assignment_properties.rb
+++ b/app/models/assignment_properties.rb
@@ -110,6 +110,12 @@ class AssignmentProperties < ApplicationRecord
   end
 
   validates :scanned_exam, inclusion: { in: [true, false] }
+  validates :allow_remarks, inclusion: { in: [true, false] }
+  validates :anonymize_groups, inclusion: { in: [true, false] }
+  validates :hide_unassigned_criteria, inclusion: { in: [true, false] }
+  validates :is_timed, inclusion: { in: [true, false] }
+  validates :starter_files_after_due, inclusion: { in: [true, false] }
+  validates :release_with_urls, inclusion: { in: [true, false] }
 
   validate :minimum_number_of_groups
 
diff --git a/app/models/course.rb b/app/models/course.rb
index a1e89ed7b5..d9d68996a3 100644
--- a/app/models/course.rb
+++ b/app/models/course.rb
@@ -48,7 +48,7 @@ class Course < ApplicationRecord
   # Note rails provides built-in sanitization via active record.
   validates :display_name, presence: true
   validates :is_hidden, inclusion: { in: [true, false] }
-  validates :max_file_size, numericality: { greater_than_or_equal_to: 0 }
+  validates :max_file_size, presence: true, numericality: { greater_than_or_equal_to: 0 }
   validate :start_at_before_or_equal_to_end_at
 
   after_save_commit :update_repo_max_file_size
diff --git a/app/models/criterion.rb b/app/models/criterion.rb
index 95c3761c59..ec8c4aab6a 100644
--- a/app/models/criterion.rb
+++ b/app/models/criterion.rb
@@ -50,6 +50,11 @@ class Criterion < ApplicationRecord
   validates :name, uniqueness: { scope: :assessment_id }
 
   validates :bonus, inclusion: { in: [true, false] }
+  validates :type, presence: true
+  validates :position, presence: true
+  validates :ta_visible, inclusion: { in: [true, false] }
+  validates :peer_visible, inclusion: { in: [true, false] }
+  validates :description, exclusion: { in: [nil] }
 
   validates :max_mark, presence: true
   validates :max_mark, numericality: { greater_than: 0 }
@@ -79,6 +84,7 @@ def update_assigned_groups_count
   def self.randomly_assign_tas(criterion_ids, ta_ids, assignment)
     assign_tas(criterion_ids, ta_ids, assignment) do |c_ids, t_ids|
       # Assign TAs in a round-robin fashion to a list of random criteria.
+      next [] if t_ids.empty?
       shuffled_criterion_ids = c_ids.shuffle
       shuffled_criterion_ids.zip(t_ids.cycle).map(&:flatten)
     end
diff --git a/app/models/exam_template.rb b/app/models/exam_template.rb
index 687ecd0836..b66defcccb 100644
--- a/app/models/exam_template.rb
+++ b/app/models/exam_template.rb
@@ -40,6 +40,8 @@ class ExamTemplate < ApplicationRecord
             length: { maximum: 20 }
   validates :num_pages, numericality: { greater_than_or_equal_to: 0,
                                         only_integer: true }
+  validates :automatic_parsing, inclusion: { in: [true, false] }
+  validates :cover_fields, exclusion: { in: [nil] }
 
   has_many :split_pdf_logs, dependent: :destroy
   has_many :template_divisions, dependent: :destroy
diff --git a/app/models/extension.rb b/app/models/extension.rb
index eb5a70cc86..bcf2503bb7 100644
--- a/app/models/extension.rb
+++ b/app/models/extension.rb
@@ -27,7 +27,8 @@ class Extension < ApplicationRecord
 
   attribute :time_delta, :interval
 
-  validates :time_delta, numericality: { greater_than: 0 }
+  validates :time_delta, presence: true, numericality: { greater_than: 0 }
+  validates :apply_penalty, inclusion: { in: [true, false] }
 
   after_create :validate_grouping
 
diff --git a/app/models/grade_entry_item.rb b/app/models/grade_entry_item.rb
index d251e1df47..b1d2cb12e1 100755
--- a/app/models/grade_entry_item.rb
+++ b/app/models/grade_entry_item.rb
@@ -38,6 +38,7 @@ class GradeEntryItem < ApplicationRecord
 
   validates :position, presence: true
   validates :position, numericality: { greater_than_or_equal_to: 0 }
+  validates :bonus, inclusion: { in: [true, false] }
 
   BLANK_MARK = ''.freeze
 
diff --git a/app/models/grade_entry_student.rb b/app/models/grade_entry_student.rb
index c0d9067ee1..a191fe8321 100644
--- a/app/models/grade_entry_student.rb
+++ b/app/models/grade_entry_student.rb
@@ -74,6 +74,7 @@ def self.randomly_assign_tas(student_ids, ta_ids, form)
     assign_tas(student_ids, ta_ids, form) do |grade_entry_student_ids, tids|
       # Assign TAs in a round-robin fashion to a list of random grade entry
       # students.
+      next [] if tids.empty?
       grade_entry_student_ids.shuffle.zip(tids.cycle)
     end
   end
diff --git a/app/models/grader_permission.rb b/app/models/grader_permission.rb
index f5ea8d1970..67cbf78c6e 100644
--- a/app/models/grader_permission.rb
+++ b/app/models/grader_permission.rb
@@ -22,4 +22,8 @@
 class GraderPermission < ApplicationRecord
   belongs_to :ta, class_name: 'Ta', foreign_key: :role_id, inverse_of: :grader_permission
   has_one :course, through: :ta
+
+  validates :manage_assessments, inclusion: { in: [true, false] }
+  validates :manage_submissions, inclusion: { in: [true, false] }
+  validates :run_tests, inclusion: { in: [true, false] }
 end
diff --git a/app/models/grouping.rb b/app/models/grouping.rb
index fe8bfd2296..1981ae7407 100644
--- a/app/models/grouping.rb
+++ b/app/models/grouping.rb
@@ -124,6 +124,8 @@ class Grouping < ApplicationRecord
   has_one :course, through: :assignment
 
   validates :is_collected, inclusion: { in: [true, false] }
+  validates :instructor_approved, inclusion: { in: [true, false] }
+  validates :starter_file_changed, inclusion: { in: [true, false] }
 
   validates :test_tokens, presence: true
   validates :test_tokens, numericality: { greater_than_or_equal_to: 0, only_integer: true }
diff --git a/app/models/lti_client.rb b/app/models/lti_client.rb
index 83293acba8..866c5f482c 100644
--- a/app/models/lti_client.rb
+++ b/app/models/lti_client.rb
@@ -18,7 +18,8 @@
 class LtiClient < ApplicationRecord
   has_many :lti_deployments
   has_many :lti_users
-  validates :client_id, uniqueness: { scope: :host }
+  validates :client_id, presence: true, uniqueness: { scope: :host }
+  validates :host, presence: true
   include Rails.application.routes.url_helpers
 
   KEY_PATH = File.join(Settings.file_storage.lti || File.join(Settings.file_storage.default_root_path, 'lti',
diff --git a/app/models/lti_deployment.rb b/app/models/lti_deployment.rb
index 0b6642c419..e760095c04 100644
--- a/app/models/lti_deployment.rb
+++ b/app/models/lti_deployment.rb
@@ -26,7 +26,9 @@ class LtiDeployment < ApplicationRecord
   belongs_to :lti_client
   has_many :lti_services, dependent: :destroy
   has_many :lti_line_items, dependent: :destroy
-  validates :lms_course_id, uniqueness: { scope: :lti_client }, allow_nil: true
+  validates :external_deployment_id, presence: true
+  validates :lms_course_id, presence: true, uniqueness: { scope: :lti_client }
+  validates :lms_course_name, presence: true
   # See LTI documentation for full lists of scopes/claims/roles
   # https://www.imsglobal.org/spec/lti/v1p3
   LTI_SCOPES = { names_role: 'https://purl.imsglobal.org/spec/lti-nrps/scope/contextmembership.readonly',
diff --git a/app/models/lti_line_item.rb b/app/models/lti_line_item.rb
index b921a25003..f57c16b1d3 100644
--- a/app/models/lti_line_item.rb
+++ b/app/models/lti_line_item.rb
@@ -26,4 +26,5 @@ class LtiLineItem < ApplicationRecord
   belongs_to :assessment
   belongs_to :lti_deployment
   validates :assessment, uniqueness: { scope: :lti_deployment_id }
+  validates :lti_line_item_id, presence: true
 end
diff --git a/app/models/lti_service.rb b/app/models/lti_service.rb
index 985885d837..550e4c4bec 100644
--- a/app/models/lti_service.rb
+++ b/app/models/lti_service.rb
@@ -28,4 +28,5 @@ class LtiService < ApplicationRecord
   belongs_to :lti_deployment
   validates :service_type, inclusion: { in: LTI_SERVICES.values }
   validates :service_type, uniqueness: { scope: :lti_deployment_id }
+  validates :url, presence: true
 end
diff --git a/app/models/lti_user.rb b/app/models/lti_user.rb
index 5bd4c7605e..f28dc0ba34 100644
--- a/app/models/lti_user.rb
+++ b/app/models/lti_user.rb
@@ -20,5 +20,5 @@
 class LtiUser < ApplicationRecord
   belongs_to :lti_client
   belongs_to :user
-  validates :lti_user_id, uniqueness: { scope: :lti_client_id }
+  validates :lti_user_id, presence: true, uniqueness: { scope: :lti_client_id }
 end
diff --git a/app/models/result.rb b/app/models/result.rb
index b776464f79..8174db8a0b 100644
--- a/app/models/result.rb
+++ b/app/models/result.rb
@@ -47,6 +47,7 @@ class Result < ApplicationRecord
   validates :marking_state, inclusion: { in: MARKING_STATES.values }
 
   validates :released_to_students, inclusion: { in: [true, false] }
+  validates :view_token, presence: true
 
   before_update :check_for_released
 
diff --git a/app/models/role.rb b/app/models/role.rb
index 69156217fe..d58eb6f686 100644
--- a/app/models/role.rb
+++ b/app/models/role.rb
@@ -52,7 +52,11 @@ class Role < ApplicationRecord
   has_many :last_updated_grades, class_name: 'Grade', foreign_key: 'last_updated_by_id', inverse_of: :last_updated_by,
                                  dependent: :nullify
 
-  validates :type, format: { with: /\AStudent|Instructor|Ta|AdminRole\z/ }
+  validates :type, presence: true, format: { with: /\AStudent|Instructor|Ta|AdminRole\z/ }
+  validates :grace_credits, presence: true
+  validates :hidden, inclusion: { in: [true, false] }
+  validates :receives_invite_emails, inclusion: { in: [true, false] }
+  validates :receives_results_emails, inclusion: { in: [true, false] }
   validates :user_id, uniqueness: { scope: :course_id }
   after_update_commit :update_repo_permissions
 
diff --git a/app/models/split_pdf_log.rb b/app/models/split_pdf_log.rb
index 6d69edbf5a..8b4b1dfdec 100644
--- a/app/models/split_pdf_log.rb
+++ b/app/models/split_pdf_log.rb
@@ -39,6 +39,7 @@ class SplitPdfLog < ApplicationRecord
   validates :num_groups_in_complete, :num_groups_in_complete, :num_pages_qr_scan_error, :original_num_pages,
             numericality: { greater_than_or_equal_to: 0,
                             only_integer: true }
+  validates :qr_code_found, inclusion: { in: [true, false] }
 
   validate :courses_should_match
 
diff --git a/app/models/starter_file_entry.rb b/app/models/starter_file_entry.rb
index abc78a5259..4a9bb126d5 100644
--- a/app/models/starter_file_entry.rb
+++ b/app/models/starter_file_entry.rb
@@ -20,6 +20,7 @@
 class StarterFileEntry < ApplicationRecord
   belongs_to :starter_file_group
   has_one :course, through: :starter_file_group
+  validates :path, presence: true
   validate :entry_exists, if: :starter_file_group
 
   has_many :grouping_starter_file_entries, dependent: :destroy
diff --git a/app/models/starter_file_group.rb b/app/models/starter_file_group.rb
index 9e50293e3d..3495c9a66c 100644
--- a/app/models/starter_file_group.rb
+++ b/app/models/starter_file_group.rb
@@ -39,6 +39,7 @@ class StarterFileGroup < ApplicationRecord
 
   validates :entry_rename, exclusion: { in: %w[.. .] }
   validates :entry_rename, presence: { if: -> { self.use_rename } }
+  validates :use_rename, inclusion: { in: [true, false] }
 
   def path
     Pathname.new(assignment.starter_file_path) + id.to_s
diff --git a/app/models/student.rb b/app/models/student.rb
index b63c2b60cf..a05e8c0f65 100644
--- a/app/models/student.rb
+++ b/app/models/student.rb
@@ -70,10 +70,6 @@ class Student < Role
 
   validates :section, presence: { unless: -> { section_id.nil? } }
 
-  validates :receives_invite_emails, inclusion: { in: [true, false] }
-
-  validates :receives_results_emails, inclusion: { in: [true, false] }
-
   validates :grace_credits,
             numericality: { only_integer: true,
                             greater_than_or_equal_to: 0 }
@@ -149,7 +145,7 @@ def create_group_for_working_alone_student(aid)
       if @assignment.is_timed
         # must use a new group for timed assignments so that repos are
         # not accessible before the student starts the timer
-        @group = Group.new(course: @assignment.course)
+        @group = Group.new(course: @assignment.course, group_name: SecureRandom.uuid)
         @group.save(validate: false)
         @group.group_name = @group.get_autogenerated_group_name
       else
@@ -188,9 +184,9 @@ def create_group_for_working_alone_student(aid)
 
   def create_autogenerated_name_group(assignment)
     Group.transaction do
-      group = Group.new(course: assignment.course)
+      group = Group.new(course: assignment.course, group_name: SecureRandom.uuid)
       group.save(validate: false)
-      group.group_name = group.get_autogenerated_group_name # the autogen name depends on the id, hence the two saves
+      group.group_name = group.get_autogenerated_group_name
       group.save
       grouping = Grouping.create(assignment: assignment, group_id: group.id)
       StudentMembership.create(grouping_id: grouping.id, membership_status: StudentMembership::STATUSES[:inviter],
diff --git a/app/models/submission.rb b/app/models/submission.rb
index b781f5f610..b5df6e449f 100644
--- a/app/models/submission.rb
+++ b/app/models/submission.rb
@@ -29,6 +29,7 @@ class Submission < ApplicationRecord
 
   validates :submission_version_used, inclusion: { in: [true, false] }
   validates :submission_version, numericality: { only_integer: true }
+  validates :is_empty, inclusion: { in: [true, false] }
   validate :max_number_of_results
   belongs_to :grouping
 
diff --git a/app/models/submission_file.rb b/app/models/submission_file.rb
index 8e6b0502fe..6851b45ea1 100644
--- a/app/models/submission_file.rb
+++ b/app/models/submission_file.rb
@@ -33,6 +33,7 @@ class SubmissionFile < ApplicationRecord
   validates :path, presence: true
 
   validates :is_converted, inclusion: { in: [true, false] }
+  validates :error_converting, inclusion: { in: [true, false] }
 
   def is_supported_image?
     # Here you can add more image types to support
diff --git a/app/models/template_division.rb b/app/models/template_division.rb
index 2d18016f41..ad9684386b 100644
--- a/app/models/template_division.rb
+++ b/app/models/template_division.rb
@@ -31,14 +31,14 @@ class TemplateDivision < ApplicationRecord
   accepts_nested_attributes_for :assignment_file, allow_destroy: true
 
   validate :courses_should_match
-  validates :start, numericality: { greater_than_or_equal_to: 2,
-                                    less_than_or_equal_to: :end,
-                                    only_integer: true }
-  validates :end, numericality: { only_integer: true }
+  validates :start, presence: true, numericality: { greater_than_or_equal_to: 2,
+                                                    less_than_or_equal_to: :end,
+                                                    only_integer: true }
+  validates :end, presence: true, numericality: { only_integer: true }
   validate :end_should_be_less_than_or_equal_to_num_pages
-  validates :label,
-            uniqueness: { scope: :exam_template,
-                          allow_blank: false }
+  validates :label, presence: true,
+                    uniqueness: { scope: :exam_template,
+                                  allow_blank: false }
 
   after_save :set_defaults_for_assignment_file # when template division is created or updated
 
diff --git a/app/models/test_group.rb b/app/models/test_group.rb
index a8e228846b..670b1e542e 100644
--- a/app/models/test_group.rb
+++ b/app/models/test_group.rb
@@ -35,6 +35,8 @@ class TestGroup < ApplicationRecord
 
   validates :name, presence: true
   validates :display_output, presence: true
+  validates :autotest_settings, exclusion: { in: [nil] }
+  validates :position, presence: true
   validate :courses_should_match
 
   def to_json(*_args)
diff --git a/app/models/test_result.rb b/app/models/test_result.rb
index c76e33e214..d74cf97858 100644
--- a/app/models/test_result.rb
+++ b/app/models/test_result.rb
@@ -31,6 +31,7 @@ class TestResult < ApplicationRecord
   validates :name, presence: true, uniqueness: { scope: :test_group_result }
   validates :status, presence: true, inclusion: { in: %w[pass partial fail error error_all] }
   validates :marks_earned, :marks_total, presence: true, numericality: { greater_than_or_equal_to: 0 }
+  validates :position, presence: true
   validates :time, numericality: { greater_than_or_equal_to: 0, only_integer: true, allow_nil: true }
   # output could be empty in some situations
   validates :output, presence: true, if: ->(o) { o.output.nil? }
diff --git a/app/models/test_run.rb b/app/models/test_run.rb
index 4cc18420b0..1f941dd941 100644
--- a/app/models/test_run.rb
+++ b/app/models/test_run.rb
@@ -41,6 +41,7 @@ class TestRun < ApplicationRecord
 
   has_one :course, through: :role
 
+  validates :status, presence: true
   validate :courses_should_match
   validate :autotest_test_id_uniqueness
   before_save :unset_autotest_test_id
diff --git a/app/models/user.rb b/app/models/user.rb
index 55dedb7175..0817ac22ba 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -45,7 +45,7 @@ class User < ApplicationRecord
   has_many :lti_users, dependent: :destroy
   validates :type, format: { with: /\AEndUser|AutotestUser|AdminUser\z/ }
 
-  validates :user_name, :last_name, :first_name, :time_zone, :display_name, presence: true
+  validates :user_name, :last_name, :first_name, :time_zone, :display_name, :theme, presence: true
   validates :user_name, uniqueness: true
   validates :email, uniqueness: { allow_nil: true }
   validates :id_number, uniqueness: { allow_nil: true }
diff --git a/db/migrate/20260526021351_enforce_not_null_constraints.rb b/db/migrate/20260526021351_enforce_not_null_constraints.rb
new file mode 100644
index 0000000000..a9fe98a057
--- /dev/null
+++ b/db/migrate/20260526021351_enforce_not_null_constraints.rb
@@ -0,0 +1,131 @@
+class EnforceNotNullConstraints < ActiveRecord::Migration[8.1]
+  def change
+    change_column_null :users, :first_name, false
+    change_column_null :users, :last_name, false
+    change_column_null :users, :created_at, false
+    change_column_null :users, :updated_at, false
+
+    change_column_null :annotations, :annotation_text_id, false
+    change_column_null :annotations, :submission_file_id, false
+    change_column_null :annotations, :annotation_number, false
+    change_column_null :annotations, :result_id, false
+
+    change_column_null :annotation_categories, :annotation_category_name, false
+    change_column_null :annotation_categories, :created_at, false
+    change_column_null :annotation_categories, :updated_at, false
+
+    change_column_null :annotation_texts, :created_at, false
+    change_column_null :annotation_texts, :updated_at, false
+
+    change_column_null :assessment_section_properties, :section_id, false
+    change_column_null :assessment_section_properties, :assessment_id, false
+
+    change_column_null :assignment_files, :created_at, false
+    change_column_null :assignment_files, :updated_at, false
+    change_column_null :assignment_files, :assessment_id, false
+
+    change_column_null :assignment_properties, :assessment_id, false
+
+    change_column_null :criteria_assignment_files_joins, :created_at, false
+    change_column_null :criteria_assignment_files_joins, :updated_at, false
+
+    change_column_null :criterion_ta_associations, :ta_id, false
+    change_column_null :criterion_ta_associations, :criterion_id, false
+    change_column_null :criterion_ta_associations, :created_at, false
+    change_column_null :criterion_ta_associations, :updated_at, false
+    change_column_null :criterion_ta_associations, :assessment_id, false
+
+    change_column_null :exam_templates, :assessment_id, false
+
+    change_column_null :extra_marks, :result_id, false
+    change_column_null :extra_marks, :created_at, false
+    change_column_null :extra_marks, :updated_at, false
+    change_column_null :extra_marks, :unit, false
+
+    change_column_null :grace_period_deductions, :created_at, false
+    change_column_null :grace_period_deductions, :updated_at, false
+
+    change_column_null :submission_rules, :created_at, false
+    change_column_null :submission_rules, :updated_at, false
+
+    change_column_null :grades, :grade_entry_item_id, false
+    change_column_null :grades, :grade_entry_student_id, false
+    change_column_null :grades, :created_at, false
+    change_column_null :grades, :updated_at, false
+
+    change_column_null :grade_entry_items, :created_at, false
+    change_column_null :grade_entry_items, :updated_at, false
+    change_column_null :grade_entry_items, :out_of, false
+    change_column_null :grade_entry_items, :position, false
+    change_column_null :grade_entry_items, :assessment_id, false
+
+    change_column_null :grade_entry_students, :created_at, false
+    change_column_null :grade_entry_students, :updated_at, false
+    change_column_null :grade_entry_students, :assessment_id, false
+
+    change_column_null :grade_entry_students_tas, :grade_entry_student_id, false
+    change_column_null :grade_entry_students_tas, :ta_id, false
+
+    change_column_null :groups, :group_name, false
+
+    change_column_null :groupings, :created_at, false
+    change_column_null :groupings, :updated_at, false
+
+    change_column_null :key_pairs, :user_id, false
+    change_column_null :key_pairs, :public_key, false
+    change_column_null :key_pairs, :created_at, false
+    change_column_null :key_pairs, :updated_at, false
+
+    change_column_null :marks, :result_id, false
+    change_column_null :marks, :criterion_id, false
+    change_column_null :marks, :created_at, false
+    change_column_null :marks, :updated_at, false
+
+    change_column_null :marking_schemes, :created_at, false
+    change_column_null :marking_schemes, :updated_at, false
+
+    change_column_null :marking_weights, :marking_scheme_id, false
+    change_column_null :marking_weights, :created_at, false
+    change_column_null :marking_weights, :updated_at, false
+
+    change_column_null :memberships, :created_at, false
+    change_column_null :memberships, :updated_at, false
+
+    change_column_null :notes, :created_at, false
+    change_column_null :notes, :updated_at, false
+
+    change_column_null :periods, :submission_rule_id, false
+    change_column_null :periods, :created_at, false
+    change_column_null :periods, :updated_at, false
+    change_column_null :periods, :submission_rule_type, false
+
+    change_column_null :results, :submission_id, false
+    change_column_null :results, :marking_state, false
+    change_column_null :results, :created_at, false
+    change_column_null :results, :updated_at, false
+
+    change_column_null :sections, :name, false
+    change_column_null :sections, :created_at, false
+    change_column_null :sections, :updated_at, false
+
+    change_column_null :split_pages, :split_pdf_log_id, false
+
+    change_column_null :split_pdf_logs, :filename, false
+    change_column_null :split_pdf_logs, :num_groups_in_complete, false
+    change_column_null :split_pdf_logs, :num_groups_in_incomplete, false
+    change_column_null :split_pdf_logs, :num_pages_qr_scan_error, false
+    change_column_null :split_pdf_logs, :original_num_pages, false
+    change_column_null :split_pdf_logs, :exam_template_id, false
+
+    change_column_null :submissions, :grouping_id, false
+    change_column_null :submissions, :created_at, false
+
+    change_column_null :submission_files, :submission_id, false
+    change_column_null :submission_files, :filename, false
+
+    change_column_null :template_divisions, :exam_template_id, false
+
+    change_column_null :test_results, :created_at, false
+    change_column_null :test_results, :updated_at, false
+  end
+end
diff --git a/db/structure.sql b/db/structure.sql
index 04a666dda0..0218537ff2 100644
--- a/db/structure.sql
+++ b/db/structure.sql
@@ -1,6 +1,7 @@
 SET statement_timeout = 0;
 SET lock_timeout = 0;
 SET idle_in_transaction_session_timeout = 0;
+SET transaction_timeout = 0;
 SET client_encoding = 'UTF8';
 SET standard_conforming_strings = on;
 SELECT pg_catalog.set_config('search_path', '', false);
@@ -144,10 +145,10 @@ SET default_table_access_method = heap;
 
 CREATE TABLE public.annotation_categories (
     id integer NOT NULL,
-    annotation_category_name text,
+    annotation_category_name text NOT NULL,
     "position" integer,
-    created_at timestamp without time zone,
-    updated_at timestamp without time zone,
+    created_at timestamp without time zone NOT NULL,
+    updated_at timestamp without time zone NOT NULL,
     assessment_id bigint NOT NULL,
     flexible_criterion_id bigint
 );
@@ -181,8 +182,8 @@ CREATE TABLE public.annotation_texts (
     id integer NOT NULL,
     content text,
     annotation_category_id integer,
-    created_at timestamp without time zone,
-    updated_at timestamp without time zone,
+    created_at timestamp without time zone NOT NULL,
+    updated_at timestamp without time zone NOT NULL,
     creator_id integer,
     last_editor_id integer,
     deduction double precision
@@ -217,21 +218,21 @@ CREATE TABLE public.annotations (
     id integer NOT NULL,
     line_start integer,
     line_end integer,
-    annotation_text_id integer,
-    submission_file_id integer,
+    annotation_text_id integer NOT NULL,
+    submission_file_id integer NOT NULL,
     x1 integer,
     x2 integer,
     y1 integer,
     y2 integer,
     type character varying,
-    annotation_number integer,
+    annotation_number integer NOT NULL,
     is_remark boolean DEFAULT false NOT NULL,
     page integer,
     column_start integer,
     column_end integer,
     creator_type character varying,
     creator_id integer,
-    result_id integer,
+    result_id integer NOT NULL,
     start_node character varying,
     end_node character varying,
     start_offset integer,
@@ -278,8 +279,8 @@ CREATE TABLE public.ar_internal_metadata (
 CREATE TABLE public.assessment_section_properties (
     id integer NOT NULL,
     due_date timestamp without time zone,
-    section_id integer,
-    assessment_id bigint,
+    section_id integer NOT NULL,
+    assessment_id bigint NOT NULL,
     start_time timestamp without time zone,
     is_hidden boolean,
     visible_on timestamp(6) without time zone,
@@ -356,9 +357,9 @@ ALTER SEQUENCE public.assessments_id_seq OWNED BY public.assessments.id;
 CREATE TABLE public.assignment_files (
     id integer NOT NULL,
     filename character varying NOT NULL,
-    created_at timestamp without time zone,
-    updated_at timestamp without time zone,
-    assessment_id bigint
+    created_at timestamp without time zone NOT NULL,
+    updated_at timestamp without time zone NOT NULL,
+    assessment_id bigint NOT NULL
 );
 
 
@@ -388,7 +389,7 @@ ALTER SEQUENCE public.assignment_files_id_seq OWNED BY public.assignment_files.i
 
 CREATE TABLE public.assignment_properties (
     id integer NOT NULL,
-    assessment_id bigint,
+    assessment_id bigint NOT NULL,
     group_min integer DEFAULT 1 NOT NULL,
     group_max integer DEFAULT 1 NOT NULL,
     student_form_groups boolean DEFAULT false NOT NULL,
@@ -551,8 +552,8 @@ CREATE TABLE public.criteria_assignment_files_joins (
     id integer NOT NULL,
     criterion_id integer NOT NULL,
     assignment_file_id integer NOT NULL,
-    created_at timestamp without time zone,
-    updated_at timestamp without time zone
+    created_at timestamp without time zone NOT NULL,
+    updated_at timestamp without time zone NOT NULL
 );
 
 
@@ -601,11 +602,11 @@ ALTER SEQUENCE public.criteria_id_seq OWNED BY public.criteria.id;
 
 CREATE TABLE public.criterion_ta_associations (
     id integer NOT NULL,
-    ta_id integer,
-    criterion_id integer,
-    created_at timestamp without time zone,
-    updated_at timestamp without time zone,
-    assessment_id bigint
+    ta_id integer NOT NULL,
+    criterion_id integer NOT NULL,
+    created_at timestamp without time zone NOT NULL,
+    updated_at timestamp without time zone NOT NULL,
+    assessment_id bigint NOT NULL
 );
 
 
@@ -646,7 +647,7 @@ CREATE TABLE public.exam_templates (
     crop_y numeric,
     crop_width numeric,
     crop_height numeric,
-    assessment_id bigint
+    assessment_id bigint NOT NULL
 );
 
 
@@ -710,12 +711,12 @@ ALTER SEQUENCE public.extensions_id_seq OWNED BY public.extensions.id;
 
 CREATE TABLE public.extra_marks (
     id integer NOT NULL,
-    result_id integer,
+    result_id integer NOT NULL,
     description character varying,
     extra_mark double precision,
-    created_at timestamp without time zone,
-    updated_at timestamp without time zone,
-    unit character varying
+    created_at timestamp without time zone NOT NULL,
+    updated_at timestamp without time zone NOT NULL,
+    unit character varying NOT NULL
 );
 
 
@@ -783,8 +784,8 @@ CREATE TABLE public.grace_period_deductions (
     id integer NOT NULL,
     membership_id integer,
     deduction integer,
-    created_at timestamp without time zone,
-    updated_at timestamp without time zone
+    created_at timestamp without time zone NOT NULL,
+    updated_at timestamp without time zone NOT NULL
 );
 
 
@@ -815,12 +816,12 @@ ALTER SEQUENCE public.grace_period_deductions_id_seq OWNED BY public.grace_perio
 CREATE TABLE public.grade_entry_items (
     id integer NOT NULL,
     name character varying NOT NULL,
-    created_at timestamp without time zone,
-    updated_at timestamp without time zone,
-    out_of double precision,
-    "position" integer,
+    created_at timestamp without time zone NOT NULL,
+    updated_at timestamp without time zone NOT NULL,
+    out_of double precision NOT NULL,
+    "position" integer NOT NULL,
     bonus boolean DEFAULT false NOT NULL,
-    assessment_id bigint
+    assessment_id bigint NOT NULL
 );
 
 
@@ -851,9 +852,9 @@ ALTER SEQUENCE public.grade_entry_items_id_seq OWNED BY public.grade_entry_items
 CREATE TABLE public.grade_entry_students (
     id integer NOT NULL,
     released_to_student boolean DEFAULT false NOT NULL,
-    created_at timestamp without time zone,
-    updated_at timestamp without time zone,
-    assessment_id bigint,
+    created_at timestamp without time zone NOT NULL,
+    updated_at timestamp without time zone NOT NULL,
+    assessment_id bigint NOT NULL,
     role_id bigint NOT NULL
 );
 
@@ -883,8 +884,8 @@ ALTER SEQUENCE public.grade_entry_students_id_seq OWNED BY public.grade_entry_st
 --
 
 CREATE TABLE public.grade_entry_students_tas (
-    grade_entry_student_id integer,
-    ta_id integer,
+    grade_entry_student_id integer NOT NULL,
+    ta_id integer NOT NULL,
     id integer NOT NULL
 );
 
@@ -947,11 +948,11 @@ ALTER SEQUENCE public.grader_permissions_id_seq OWNED BY public.grader_permissio
 
 CREATE TABLE public.grades (
     id integer NOT NULL,
-    grade_entry_item_id integer,
-    grade_entry_student_id integer,
+    grade_entry_item_id integer NOT NULL,
+    grade_entry_student_id integer NOT NULL,
     grade double precision,
-    created_at timestamp without time zone,
-    updated_at timestamp without time zone,
+    created_at timestamp without time zone NOT NULL,
+    updated_at timestamp without time zone NOT NULL,
     last_updated_by_id bigint
 );
 
@@ -1013,8 +1014,8 @@ ALTER SEQUENCE public.grouping_starter_file_entries_id_seq OWNED BY public.group
 CREATE TABLE public.groupings (
     id integer NOT NULL,
     group_id integer NOT NULL,
-    created_at timestamp without time zone,
-    updated_at timestamp without time zone,
+    created_at timestamp without time zone NOT NULL,
+    updated_at timestamp without time zone NOT NULL,
     instructor_approved boolean DEFAULT false NOT NULL,
     is_collected boolean DEFAULT false NOT NULL,
     criteria_coverage_count integer DEFAULT 0,
@@ -1061,7 +1062,7 @@ CREATE TABLE public.groupings_tags (
 
 CREATE TABLE public.groups (
     id integer NOT NULL,
-    group_name character varying,
+    group_name character varying NOT NULL,
     repo_name character varying,
     course_id bigint NOT NULL
 );
@@ -1127,10 +1128,10 @@ ALTER SEQUENCE public.job_messengers_id_seq OWNED BY public.job_messengers.id;
 
 CREATE TABLE public.key_pairs (
     id integer NOT NULL,
-    user_id integer,
-    public_key character varying,
-    created_at timestamp without time zone,
-    updated_at timestamp without time zone
+    user_id integer NOT NULL,
+    public_key character varying NOT NULL,
+    created_at timestamp without time zone NOT NULL,
+    updated_at timestamp without time zone NOT NULL
 );
 
 
@@ -1365,8 +1366,8 @@ ALTER SEQUENCE public.lti_users_id_seq OWNED BY public.lti_users.id;
 CREATE TABLE public.marking_schemes (
     id integer NOT NULL,
     name character varying,
-    created_at timestamp without time zone,
-    updated_at timestamp without time zone,
+    created_at timestamp without time zone NOT NULL,
+    updated_at timestamp without time zone NOT NULL,
     course_id bigint NOT NULL
 );
 
@@ -1397,10 +1398,10 @@ ALTER SEQUENCE public.marking_schemes_id_seq OWNED BY public.marking_schemes.id;
 
 CREATE TABLE public.marking_weights (
     id integer NOT NULL,
-    marking_scheme_id integer,
+    marking_scheme_id integer NOT NULL,
     weight numeric,
-    created_at timestamp without time zone,
-    updated_at timestamp without time zone,
+    created_at timestamp without time zone NOT NULL,
+    updated_at timestamp without time zone NOT NULL,
     assessment_id bigint NOT NULL
 );
 
@@ -1431,11 +1432,11 @@ ALTER SEQUENCE public.marking_weights_id_seq OWNED BY public.marking_weights.id;
 
 CREATE TABLE public.marks (
     id integer NOT NULL,
-    result_id integer,
-    criterion_id integer,
+    result_id integer NOT NULL,
+    criterion_id integer NOT NULL,
     mark double precision,
-    created_at timestamp without time zone,
-    updated_at timestamp without time zone,
+    created_at timestamp without time zone NOT NULL,
+    updated_at timestamp without time zone NOT NULL,
     override boolean DEFAULT false NOT NULL,
     last_updated_by_id bigint
 );
@@ -1468,8 +1469,8 @@ ALTER SEQUENCE public.marks_id_seq OWNED BY public.marks.id;
 CREATE TABLE public.memberships (
     id integer NOT NULL,
     membership_status character varying,
-    created_at timestamp without time zone,
-    updated_at timestamp without time zone,
+    created_at timestamp without time zone NOT NULL,
+    updated_at timestamp without time zone NOT NULL,
     grouping_id integer NOT NULL,
     type character varying,
     role_id bigint NOT NULL
@@ -1504,8 +1505,8 @@ CREATE TABLE public.notes (
     id integer NOT NULL,
     notes_message text NOT NULL,
     creator_id integer NOT NULL,
-    created_at timestamp without time zone,
-    updated_at timestamp without time zone,
+    created_at timestamp without time zone NOT NULL,
+    updated_at timestamp without time zone NOT NULL,
     noteable_type character varying NOT NULL,
     noteable_id integer NOT NULL
 );
@@ -1570,13 +1571,13 @@ ALTER SEQUENCE public.peer_reviews_id_seq OWNED BY public.peer_reviews.id;
 
 CREATE TABLE public.periods (
     id integer NOT NULL,
-    submission_rule_id integer,
+    submission_rule_id integer NOT NULL,
     deduction double precision,
-    created_at timestamp without time zone,
-    updated_at timestamp without time zone,
+    created_at timestamp without time zone NOT NULL,
+    updated_at timestamp without time zone NOT NULL,
     hours double precision,
     "interval" double precision,
-    submission_rule_type character varying
+    submission_rule_type character varying NOT NULL
 );
 
 
@@ -1606,11 +1607,11 @@ ALTER SEQUENCE public.periods_id_seq OWNED BY public.periods.id;
 
 CREATE TABLE public.results (
     id integer NOT NULL,
-    submission_id integer,
-    marking_state character varying,
+    submission_id integer NOT NULL,
+    marking_state character varying NOT NULL,
     overall_comment text,
-    created_at timestamp without time zone,
-    updated_at timestamp without time zone,
+    created_at timestamp without time zone NOT NULL,
+    updated_at timestamp without time zone NOT NULL,
     released_to_students boolean DEFAULT false NOT NULL,
     remark_request_submitted_at timestamp without time zone,
     view_token character varying NOT NULL,
@@ -1721,9 +1722,9 @@ ALTER SEQUENCE public.section_starter_file_groups_id_seq OWNED BY public.section
 
 CREATE TABLE public.sections (
     id integer NOT NULL,
-    name character varying,
-    created_at timestamp without time zone,
-    updated_at timestamp without time zone,
+    name character varying NOT NULL,
+    created_at timestamp without time zone NOT NULL,
+    updated_at timestamp without time zone NOT NULL,
     course_id bigint NOT NULL
 );
 
@@ -1791,7 +1792,7 @@ CREATE TABLE public.split_pages (
     exam_page_number integer,
     filename character varying,
     status character varying,
-    split_pdf_log_id integer,
+    split_pdf_log_id integer NOT NULL,
     group_id integer,
     created_at timestamp without time zone NOT NULL,
     updated_at timestamp without time zone NOT NULL
@@ -1826,15 +1827,15 @@ CREATE TABLE public.split_pdf_logs (
     id integer NOT NULL,
     uploaded_when timestamp without time zone,
     error_description character varying,
-    filename character varying,
-    num_groups_in_complete integer,
-    num_groups_in_incomplete integer,
-    num_pages_qr_scan_error integer,
-    original_num_pages integer,
+    filename character varying NOT NULL,
+    num_groups_in_complete integer NOT NULL,
+    num_groups_in_incomplete integer NOT NULL,
+    num_pages_qr_scan_error integer NOT NULL,
+    original_num_pages integer NOT NULL,
     qr_code_found boolean DEFAULT false NOT NULL,
     created_at timestamp without time zone NOT NULL,
     updated_at timestamp without time zone NOT NULL,
-    exam_template_id integer,
+    exam_template_id integer NOT NULL,
     role_id bigint NOT NULL
 );
 
@@ -1927,8 +1928,8 @@ ALTER SEQUENCE public.starter_file_groups_id_seq OWNED BY public.starter_file_gr
 
 CREATE TABLE public.submission_files (
     id integer NOT NULL,
-    submission_id integer,
-    filename character varying,
+    submission_id integer NOT NULL,
+    filename character varying NOT NULL,
     path character varying DEFAULT '/'::character varying NOT NULL,
     is_converted boolean DEFAULT false NOT NULL,
     error_converting boolean DEFAULT false NOT NULL
@@ -1962,8 +1963,8 @@ ALTER SEQUENCE public.submission_files_id_seq OWNED BY public.submission_files.i
 CREATE TABLE public.submission_rules (
     id integer NOT NULL,
     type character varying DEFAULT 'NoLateSubmissionRule'::character varying,
-    created_at timestamp without time zone,
-    updated_at timestamp without time zone,
+    created_at timestamp without time zone NOT NULL,
+    updated_at timestamp without time zone NOT NULL,
     assessment_id bigint NOT NULL,
     penalty_type character varying DEFAULT 'percentage'::character varying
 );
@@ -1995,8 +1996,8 @@ ALTER SEQUENCE public.submission_rules_id_seq OWNED BY public.submission_rules.i
 
 CREATE TABLE public.submissions (
     id integer NOT NULL,
-    grouping_id integer,
-    created_at timestamp without time zone,
+    grouping_id integer NOT NULL,
+    created_at timestamp without time zone NOT NULL,
     submission_version integer,
     submission_version_used boolean DEFAULT false NOT NULL,
     revision_identifier text,
@@ -2066,7 +2067,7 @@ ALTER SEQUENCE public.tags_id_seq OWNED BY public.tags.id;
 
 CREATE TABLE public.template_divisions (
     id integer NOT NULL,
-    exam_template_id integer,
+    exam_template_id integer NOT NULL,
     start integer NOT NULL,
     "end" integer NOT NULL,
     label character varying NOT NULL,
@@ -2213,8 +2214,8 @@ CREATE TABLE public.test_results (
     status text NOT NULL,
     marks_earned double precision DEFAULT 0.0 NOT NULL,
     output text DEFAULT ''::text NOT NULL,
-    created_at timestamp without time zone,
-    updated_at timestamp without time zone,
+    created_at timestamp without time zone NOT NULL,
+    updated_at timestamp without time zone NOT NULL,
     marks_total double precision DEFAULT 0.0 NOT NULL,
     "time" bigint,
     test_group_result_id bigint NOT NULL,
@@ -2288,11 +2289,11 @@ ALTER SEQUENCE public.test_runs_id_seq OWNED BY public.test_runs.id;
 CREATE TABLE public.users (
     id integer NOT NULL,
     user_name character varying NOT NULL,
-    last_name character varying,
-    first_name character varying,
+    last_name character varying NOT NULL,
+    first_name character varying NOT NULL,
     type character varying,
-    created_at timestamp without time zone,
-    updated_at timestamp without time zone,
+    created_at timestamp without time zone NOT NULL,
+    updated_at timestamp without time zone NOT NULL,
     api_key character varying,
     email character varying,
     id_number character varying,
@@ -4453,6 +4454,7 @@ ALTER TABLE ONLY public.submission_files
 SET search_path TO "$user", public;
 
 INSERT INTO "schema_migrations" (version) VALUES
+('20260526021351'),
 ('20260415150142'),
 ('20260326174749'),
 ('20260325180720'),
diff --git a/spec/models/annotation_text_spec.rb b/spec/models/annotation_text_spec.rb
index ceb354dce2..d523c0765a 100644
--- a/spec/models/annotation_text_spec.rb
+++ b/spec/models/annotation_text_spec.rb
@@ -15,7 +15,7 @@
 
     it { is_expected.to belong_to(:annotation_category).optional }
     it { is_expected.to have_many(:annotations) }
-    it { is_expected.to belong_to(:creator) }
+    it { is_expected.to belong_to(:creator).optional }
     it { is_expected.to belong_to(:last_editor).optional }
     it { is_expected.to have_one(:course) }
 
diff --git a/spec/support/criterion.rb b/spec/support/criterion.rb
index 40fb2daf29..a8fef1b9a6 100644
--- a/spec/support/criterion.rb
+++ b/spec/support/criterion.rb
@@ -245,7 +245,7 @@ def expect_updated_assigned_groups_count_to_eq(expected_count)
                 # Creating a new criterion also creates a new assignment.
                 criterion = create(criterion_factory_name)
                 grouping = create(:grouping, assignment: criterion.assignment)
-                Criterion.assign_all_tas([[criterion.id, criterion.class.to_s]], tas.map(&:id), criterion.assignment)
+                Criterion.assign_all_tas([criterion.id], tas.map(&:id), criterion.assignment)
                 create_ta_memberships(grouping, tas)
               end