DA - speed grader shows right students and sections

fixes CNVS-13810

test plan:
  - with DA on create multiple assignments visible to
    select sections
  - go to speed grader for said assignments
    - only students with visibility should show up
    - only sections with visibility should show up
  - turn DA off and everything still works
  - note: group assingments not done yet

Change-Id: Ia065a82a24db40cc6ba46586114167e2ea8e75c1
Reviewed-on: https://gerrit.instructure.com/36981
Reviewed-by: Cameron Sutter <csutter@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
QA-Review: Amber Taniuchi <amber@instructure.com>
Product-Review: Hilary Scharton <hilary@instructure.com>

app/models/assignment.rb

@@ -1264,7 +1264,7 @@ class Assignment < ActiveRecord::Base
                 :methods => avatar_methods,
                 :only => [:name, :id])
     }
-    res[:context][:active_course_sections] = context.sections_visible_to(user).
+    res[:context][:active_course_sections] = context.sections_visible_to(user, self.sections_with_visibility(user)).
       map{|s| s.as_json(:include_root => false, :only => [:id, :name]) }
     res[:context][:enrollments] = enrollments.
         map{|s| s.as_json(:include_root => false, :only => [:user_id, :course_section_id]) }
@@ -1338,6 +1338,14 @@ class Assignment < ActiveRecord::Base
     Attachment.skip_thumbnails = nil
   end
 
+  def sections_with_visibility(user)
+    return context.active_course_sections unless self.differentiated_assignments_applies?
+
+    visible_student_ids = visible_students_for_speed_grader(user).map(&:id)
+    context.active_course_sections.joins(:student_enrollments).
+      where(:enrollments => {:user_id => visible_student_ids, :type => "StudentEnrollment"}).uniq.reorder("name")
+  end
+
   # quiz submission versions are too expensive to de-serialize so we have to
   # cap the number we will do
   def too_many_qs_versions?(student_submissions)
@@ -1374,12 +1382,6 @@ class Assignment < ActiveRecord::Base
   # group's submission.  the students name will be changed to the group's
   # name.  for non-group assignments this just returns all visible users
   def representatives(user)
-    visible_students = (
-      user ?
-        context.students_visible_to(user) :
-        context.participating_students
-    ).order_by_sortable_name.uniq.to_a
-
     if grade_as_group?
       submissions = self.submissions.includes(:user)
       users_with_submissions = submissions
@@ -1395,7 +1397,7 @@ class Assignment < ActiveRecord::Base
       group_category.groups.includes(:group_memberships => :user).map { |g|
         [g.name, g.users]
       }.map { |group_name, group_students|
-        visible_group_students = group_students & visible_students
+        visible_group_students = group_students & visible_students_for_speed_grader(user)
         representative   = (visible_group_students & users_with_turnitin_data).first
         representative ||= (visible_group_students & users_with_submissions).first
         representative ||= visible_group_students.first
@@ -1412,10 +1414,23 @@ class Assignment < ActiveRecord::Base
         representative
       }.compact
     else
-      visible_students
+      visible_students_for_speed_grader(user)
     end
   end
 
+  # using this method instead of students_with_visibility so we
+  # can add the includes and students_visible_to/participating_students scopes
+  def visible_students_for_speed_grader(user)
+    @visible_students_for_speed_grader ||= {}
+    @visible_students_for_speed_grader[user.global_id] ||= (
+      student_scope = user ? context.students_visible_to(user) : context.participating_students
+      if self.differentiated_assignments_applies?
+        student_scope = student_scope.able_to_see_assignment_in_course_with_da(self.id, context.id)
+      end
+      student_scope
+    ).order_by_sortable_name.uniq.to_a
+  end
+
   def visible_rubric_assessments_for(user)
     if self.rubric_association
       self.rubric_association.rubric_assessments.select{|a| a.grants_right?(user, :read)}.sort_by{|a| [a.assessment_type == 'grading' ? CanvasSort::First : CanvasSort::Last, Canvas::ICU.collation_key(a.assessor_name)] }

spec/models/assignment_spec.rb

@@ -1854,6 +1854,39 @@ describe Assignment do
     end
   end
 
+  describe "sections_with_visibility" do
+   before(:once) do
+     course_with_teacher(:active_all => true)
+     @course.enable_feature!(:draft_state)
+     @section = @course.course_sections.create!
+     @student = student_in_section(@section, opts={})
+     @assignment, @assignment2, @assignment3 = (1..3).map{|a|@course.assignments.create!}
+
+     @assignment.only_visible_to_overrides = true
+     create_section_override_for_assignment(@assignment, course_section: @section)
+
+     @assignment2.only_visible_to_overrides = true
+
+     @assignment3.only_visible_to_overrides = false
+     create_section_override_for_assignment(@assignment3, course_section: @section)
+     [@assignment, @assignment2, @assignment3].each(&:save!)
+   end
+
+   it "returns active_course_sections with differentiated assignments off" do
+     @course.disable_feature!(:differentiated_assignments)
+     @assignment.sections_with_visibility(@teacher).should == @course.course_sections
+     @assignment2.sections_with_visibility(@teacher).should == @course.course_sections
+     @assignment3.sections_with_visibility(@teacher).should == @course.course_sections
+   end
+
+   it "returns only sections with overrides with differentiated assignments on" do
+     @course.enable_feature!(:differentiated_assignments)
+     @assignment.sections_with_visibility(@teacher).should == [@section]
+     @assignment2.sections_with_visibility(@teacher).should == []
+     @assignment3.sections_with_visibility(@teacher).should == @course.course_sections
+   end
+ end
+
   context "modules" do
     it "should be locked when part of a locked module" do
       ag = @course.assignment_groups.create!
@@ -2321,6 +2354,52 @@ describe Assignment do
       json[:submissions].first[:submission_comments].first[:created_at].to_i.should eql @comment.created_at.to_i
     end
 
+    context "students and active course sections" do
+      before(:once) do
+        @course = course(:active_course => true)
+        @teacher, @student1, @student2 = (1..3).map{User.create}
+        @assignment = Assignment.create!(title: "title", context: @course, only_visible_to_overrides: true)
+        @course.enroll_teacher(@teacher)
+        @course.enroll_student(@student2, :enrollment_state => 'active')
+        @section1 = @course.course_sections.create!(name: "test section 1")
+        @section2 = @course.course_sections.create!(name: "test section 2")
+        student_in_section(@section1, user: @student1)
+        create_section_override_for_assignment(@assignment, {course_section: @section1})
+      end
+
+      it "should include all students and sections with DA off" do
+        @course.disable_feature!(:differentiated_assignments)
+        json = @assignment.speed_grader_json(@teacher)
+
+        json[:context][:students].map{|s| s[:id]}.include?(@student1.id).should be_true
+        json[:context][:students].map{|s| s[:id]}.include?(@student2.id).should be_true
+        json[:context][:active_course_sections].map{|cs| cs[:id]}.include?(@section1.id).should be_true
+        json[:context][:active_course_sections].map{|cs| cs[:id]}.include?(@section2.id).should be_true
+      end
+
+      it "should include only students and sections with overrides when DA is on" do
+        @course.enable_feature!(:differentiated_assignments)
+        json = @assignment.speed_grader_json(@teacher)
+
+        json[:context][:students].map{|s| s[:id]}.include?(@student1.id).should be_true
+        json[:context][:students].map{|s| s[:id]}.include?(@student2.id).should be_false
+        json[:context][:active_course_sections].map{|cs| cs[:id]}.include?(@section1.id).should be_true
+        json[:context][:active_course_sections].map{|cs| cs[:id]}.include?(@section2.id).should be_false
+      end
+
+      it "should include all students when is only_visible_to_overrides false" do
+        @course.enable_feature!(:differentiated_assignments)
+        @assignment.only_visible_to_overrides = false
+        @assignment.save!
+        json = @assignment.speed_grader_json(@teacher)
+
+        json[:context][:students].map{|s| s[:id]}.include?(@student1.id).should be_true
+        json[:context][:students].map{|s| s[:id]}.include?(@student2.id).should be_true
+        json[:context][:active_course_sections].map{|cs| cs[:id]}.include?(@section1.id).should be_true
+        json[:context][:active_course_sections].map{|cs| cs[:id]}.include?(@section2.id).should be_true
+      end
+    end
+
     it "should return submission lateness" do
       # Set up
       section_1 = @course.course_sections.create!(:name => 'Section one')