Require at least one correct submission and a valid config before publishing

app/models/activity.rb

@@ -57,6 +57,7 @@ class Activity < ApplicationRecord
   has_many :labels, through: :activity_labels
 
   validates :path, uniqueness: { scope: :repository_id, case_sensitive: false }, allow_nil: true
+  validate :require_correct_submission_before_publish, on: :update
 
   token_generator :repository_token, length: 64
   token_generator :access_token
@@ -510,4 +511,19 @@ def unique_labels(hash)
     hash['labels'] = hash['labels'].uniq if hash.key? 'labels'
     hash
   end
+
+  def correct_submission?
+    return true if content_page?
+
+    submissions.any?(&:accepted?)
+  end
+
+  def require_correct_submission_before_publish
+    return if draft?
+    return unless draft_was
+    return if correct_submission?
+
+    errors.add(:base, I18n.t('activerecord.errors.models.activity.no_correct_submission'))
+    self.draft = true
+  end
 end

config/locales/models/en.yml

@@ -2,6 +2,8 @@ en:
   activerecord:
     errors:
       models:
+        activity:
+          no_correct_submission: "At least one correct submission is required, before the exercise can be published."
         course_membership:
           at_least_one_admin: The course should always have at least one course administrator.
         api_token:

config/locales/models/nl.yml

@@ -2,6 +2,8 @@ nl:
   activerecord:
     errors:
       models:
+        activity:
+          no_correct_submission: "Er moet minstens één correcte oplossing zijn, vooraleer de oefening kan worden gepubliceerd."
         course_membership:
           at_least_one_admin: Een cursus moet altijd minstens één cursusbeheerder hebben.
         api_token:

test/controllers/activities_controller_test.rb

@@ -802,6 +802,7 @@ def create_exercises_return_valid
     repo = create :repository, :git_stubbed
     repo.admins << user
     exercise = create :exercise, repository: repo, draft: true
+    create :correct_submission, exercise: exercise
 
     put activity_url(exercise), params: { activity: { draft: false } }
 

test/models/activity_test.rb

@@ -304,4 +304,20 @@ class ActivityTest < ActiveSupport::TestCase
     assert_empty Activity.repository_scope(scope: :my_institution, user: nil)
     assert_empty Activity.repository_scope(scope: :my_institution, user: create(:user, institution_id: nil))
   end
+
+  test 'should have at least one valid submission before publishing' do
+    activity = create :exercise, draft: true
+    activity.update(draft: false)
+
+    assert_not_empty activity.errors
+    assert_predicate activity.reload, :draft?
+
+    # reset errors
+    activity = Activity.find(activity.id)
+    create :correct_submission, exercise: activity
+    activity.update(draft: false)
+
+    assert_empty activity.errors
+    assert_not activity.reload.draft?
+  end
 end