Handles section end_at extensions in Quizzes

Closes CNVS-21521

Test Plan:
  - Regression test that due_dates, closing "end_at" dates and all
    things quiz time limits/moderation are all good.
    - Good luck!

Change-Id: Id5ad6c0028e06e67caea28fce514190730a02e44
Reviewed-on: https://gerrit.instructure.com/59020
Tested-by: Jenkins
Reviewed-by: Cameron Sutter <csutter@instructure.com>
Product-Review: Pedro Fajardo <pfajardo@instructure.com>
QA-Review: Deepeeca Soundarrajan <dsoundarrajan@instructure.com>

app/models/quizzes/quiz.rb

@@ -615,6 +615,7 @@ def build_submission_end_at(submission)
     # Admins can take the full quiz whenever they want
     return end_at if user.is_a?(::User) && self.grants_right?(user, :grade)
 
+    can_take = Quizzes::QuizEligibility.new(course: self.context, quiz: self, user: submission.user)
     # set to lock date
     if lock_at && !submission.manually_unlocked
       if !end_at || lock_at < end_at
@@ -626,12 +627,19 @@ def build_submission_end_at(submission)
       if !end_at || course.end_at < end_at
         end_at = course.end_at
       end
+      # Section dates overrule
+      if can_take.section_dates_apply? && can_take.course_section.end_at > end_at
+        end_at = can_take.course_section.end_at
+      end
 
     # set to enrollment term end
     elsif course.enrollment_term.end_at
       if !end_at || course.enrollment_term.end_at < end_at
         end_at = course.enrollment_term.end_at
       end
+      if can_take.section_dates_apply? && can_take.course_section.end_at > end_at
+        end_at = can_take.course_section.end_at
+      end
     end
 
     end_at

app/models/quizzes/quiz_eligibility.rb

@@ -49,6 +49,14 @@ def locked?
     !quiz.grants_right?(user, session, :update)
   end
 
+  def section_dates_apply?
+    section_restricted_by_date? && section_is_ongoing?
+  end
+
+  def course_section
+    @course_section ||= (assignment_overrides && student_sections).first || CourseSection.new
+  end
+
   private
 
   attr_reader :course, :quiz, :user, :session, :remote_ip
@@ -144,10 +152,6 @@ def restricted_course_has_ended?
     course.restrict_enrollments_to_course_dates ? course_has_ended? : false
   end
 
-  def course_section
-    @course_section ||= (assignment_overrides & student_sections).first || CourseSection.new
-  end
-
   def inactive_non_admin?
     return false if user.new_record?
     inactive_enrollment? && user_cannot_not_read_as_admin?

spec/models/quizzes/quiz_spec.rb

@@ -599,6 +599,27 @@
       expect(sub2.end_at).to eq deadline
     end
 
+    it "should set end_at to section end dates" do
+      # when course.end_at or term.end_at doesn't exist
+      deadline = 2.days.from_now
+      @course.restrict_enrollments_to_course_dates = true
+      @course.save!
+      @course.enrollment_term.end_at = 1.day.from_now
+      @course.enrollment_term.save!
+
+      # Create a special time extension section
+      section = @course.course_sections.create!(restrict_enrollments_to_section_dates: true, end_at: deadline)
+
+      # Create user and enroll them in our section
+      user = User.create!(:name => "Fred Colon")
+      enrollment = section.enroll_user(user, "StudentEnrollment")
+      enrollment.accept(:force)
+
+      q = @course.quizzes.create!(:title => "locked tomorrow")
+      sub2 = q.generate_submission(user)
+      expect(sub2.end_at).to eq deadline
+    end
+
     it "should shuffle submission questions" do
       u1 = User.create!(:name => "user 1")
       u2 = User.create!(:name => "user 2")