preserve `only_visible_to_overrides` for page assignments

test plan:
- Enable Mastery Paths in the course or account
- Create a course with a Module and add a Page and an Assignment as module items
- Enable MP for Page
- Add Page as a conditional content to an MP assignment
- Login as a student to check that the page is not visible
- Copy course into a new course shell
- Login as a student in the child course
- The page should not be visible before it is unlocked

fixes ADMIN-1461

Change-Id: I4c0d02b33a78862edcb36914dfe531b24caad08f
Reviewed-on: https://gerrit.instructure.com/167010
Tested-by: Jenkins
QA-Review: Mysti Sadler <mysti@instructure.com>
Product-Review: Jeremy Stanley <jeremy@instructure.com>
Reviewed-by: Neil Gupta <ngupta@instructure.com>
Reviewed-by: James Williams <jamesw@instructure.com>

lib/cc/importer/canvas/wiki_converter.rb

@@ -49,7 +49,11 @@ module CC::Importer::Canvas
       wiki[:assignment] = nil
       wiki[:todo_date] = meta['todo_date']
       if asg_id = meta['assignment_identifier']
-        wiki[:assignment] = { migration_id: asg_id }
+        wiki[:assignment] = {
+          migration_id: asg_id,
+          assignment_overrides: [],
+          only_visible_to_overrides: meta['only_visible_to_overrides'] == 'true'
+        }
       end
       wiki
     end

lib/cc/wiki_resources.rb

@@ -40,8 +40,10 @@ module CC
           meta_fields[:workflow_state] = page.workflow_state
           meta_fields[:front_page] = page.is_front_page?
           meta_fields[:module_locked] = page.locked_by_module_item?(@user, deep_check_if_needed: true).present?
-          meta_fields[:assignment_identifier] =
-            page.for_assignment? ? create_key(page.assignment) : nil
+          if page.for_assignment?
+            meta_fields[:assignment_identifier] = create_key(page.assignment)
+            meta_fields[:only_visible_to_overrides] = page.assignment.only_visible_to_overrides
+          end
           meta_fields[:todo_date] = page.todo_date
 
           File.open(path, 'w') do |file|

spec/models/content_migration/course_copy_assignments_spec.rb

@@ -593,6 +593,18 @@ describe ContentMigration do
         expect(to_override.due_at_overridden).to eq true
         expect(to_override.unlock_at_overridden).to eq false
       end
+
+      it "preserves only_visible_to_overrides for page assignments" do
+        a1 = assignment_model(context: @copy_from, title: 'a1', submission_types: 'wiki_page', only_visible_to_overrides: true)
+        a1.build_wiki_page(title: a1.title, context: a1.context).save!
+        a2 = assignment_model(context: @copy_from, title: 'a2', submission_types: 'wiki_page', only_visible_to_overrides: false)
+        a2.build_wiki_page(title: a2.title, context: a2.context).save!
+        run_course_copy
+        a1_to = @copy_to.assignments.where(migration_id: mig_id(a1)).take
+        expect(a1_to.only_visible_to_overrides).to eq true
+        a2_to = @copy_to.assignments.where(migration_id: mig_id(a2)).take
+        expect(a2_to.only_visible_to_overrides).to eq false
+      end
     end
 
     context 'external tools' do