grade calculator: ignore unposted anonymous assignments

closes EVAL-1272
flag=grade_calc_ignore_unposted_anonymous

Test Plan:
1. Enable the 'Ignore Unposted Anonymous Assignments in Grade
   Calculation' release flag. Create an anonymous assignment and
   grade some students.
2. Before posting the assignment, enter a rails console and check the
   unposted_* scores for the students. Verify:
   - The unposted_* scores do not include the submission score from the
     anonymous unposted assignment.
3. Disable the 'Ignore Unposted Anonymous Assignments in Grade
   Calculation' release flag.
4. Enter a rails console again and check the unposted_* scores for the
   students. Verify:
   - The unposted_* scores include the submission score from the
     anonymous unposted assignment.
5. Post the assignment to students. Then enter a rails console again and
   verify the unposted_* scores for the students include the submission
   score from the anonymous (now posted) assignment.
6. Re-enable the 'Ignore Unposted Anonymous Assignments in Grade
   Calculation' release flag. Verify the unposted_* scores for the
   students include the submission score from the anonymous (now posted)
   assignment.

Change-Id: Ibb42b9f3164c08e3bc2a21fc02736760f58af51a
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/251786
Tested-by: Service Cloud Jenkins <svc.cloudjenkins@instructure.com>
Product-Review: Syed Hussain <shussain@instructure.com>
Reviewed-by: Adrian Packel <apackel@instructure.com>
Reviewed-by: Gary Mei <gmei@instructure.com>
QA-Review: Kai Bjorkman <kbjorkman@instructure.com>

app/models/assignment.rb

@@ -1498,6 +1498,12 @@ class Assignment < ActiveRecord::Base
   end
 
   def self.preload_unposted_anonymous_submissions(assignments)
+    # Don't do anything if there are no assignments OR unposted anonymous submissions are already preloaded
+    if assignments.is_a?(Array) &&
+      (assignments.empty? || assignments.all? { |a| !a.unposted_anonymous_submissions.nil? })
+      return
+    end
+
     assignment_ids_with_unposted_anonymous_submissions = Assignment.
       where(id: assignments, anonymous_grading: true).
       where(
@@ -1512,6 +1518,8 @@ class Assignment < ActiveRecord::Base
     assignments.each do |assignment|
       assignment.unposted_anonymous_submissions = assignment_ids_with_unposted_anonymous_submissions.include?(assignment.id)
     end
+
+    nil
   end
 
   def touch_on_unlock_if_necessary

config/feature_flags/apogee_release_flags.yml

@@ -71,3 +71,16 @@ gradebook_load_assignments_by_grading_period:
   display_name: Load Gradebook Assignments by Grading Period
   description: If set, the Gradebook will chunk out loading of assignments, loading those for the selected
     grading period first.
+grade_calc_ignore_unposted_anonymous:
+  state: hidden
+  applies_to: RootAccount
+  display_name: Ignore Unposted Anonymous Assignments in Grade Calculation
+  description: If set, the grade calculator will ignore unposted anonymous assignments when calculating
+    totals.
+  environments:
+    ci:
+      state: on # enable for automated testings builds and local testing
+    development:
+      state: on # enable for local development
+    test:
+      state: on # enable for the deployed 'test' environment

lib/grade_calculator.rb

@@ -49,7 +49,20 @@ class GradeCalculator
     # if we're updating a grading period score, we also need to update the
     # overall course score
     @update_course_score = @grading_period.present? && opts[:update_course_score]
-    @assignments = opts[:assignments] || @course.assignments.published.gradeable.to_a
+    @ignore_unposted_anonymous = opts.fetch(
+      :ignore_unposted_anonymous,
+      @course.root_account.feature_enabled?(:grade_calc_ignore_unposted_anonymous)
+    )
+    @assignments = (opts[:assignments] || @course.assignments.published.gradeable).to_a
+
+    if @ignore_unposted_anonymous
+      Assignment.preload_unposted_anonymous_submissions(@assignments)
+
+      # Ignore anonymous assignments with unposted submissions in the grade calculation
+      # so that we don't break anonymity prior to the assignment being posted
+      # (which is when identities are revealed)
+      @assignments.reject!(&:unposted_anonymous_submissions?)
+    end
 
     @user_ids = Array(user_ids).map { |id| Shard.relative_id_for(id, Shard.current, @course.shard) }
     @current_updates = {}
@@ -335,6 +348,7 @@ class GradeCalculator
       assignments: @assignments,
       emit_live_event: @emit_live_event,
       ignore_muted: @ignore_muted,
+      ignore_unposted_anonymous: @ignore_unposted_anonymous,
       periods: grading_periods_for_course,
       effective_due_dates: effective_due_dates,
       enrollments: enrollments,

spec/lib/grade_calculator_spec.rb

@@ -485,6 +485,38 @@ describe GradeCalculator do
             end
           end
 
+          context "with unposted anonymous assignments" do
+            let(:calculator) { GradeCalculator.new([@user.id], @course.id, ignore_muted: false) }
+            let(:computed_score_data) { calculator.compute_scores.first }
+
+            before(:each) do
+              @anonymized_assignment = @course.assignments.create!(anonymous_grading: true)
+              @anonymized_assignment.grade_student(@user, grade: "10", grader: @teacher)
+            end
+
+            it "does not incorporate submissions for unposted anonymous assignments" do
+              expect(computed_score_data[:current][:grade]).to eq 75.0
+            end
+
+            it "incorporates submissions for posted anonymous assignments" do
+              @anonymized_assignment.post_submissions
+              expect(computed_score_data[:current][:grade]).to eq 125.0
+            end
+
+            context "when including unposted anonymous assignments in grade calculations" do
+              let(:calculator) { GradeCalculator.new([@user.id], @course.id, ignore_muted: false, ignore_unposted_anonymous: false) }
+
+              it "incorporates submissions for unposted anonymous assignments" do
+                expect(computed_score_data[:current][:grade]).to eq 125.0
+              end
+
+              it "incorporates submissions for posted anonymous assignments" do
+                @anonymized_assignment.post_submissions
+                expect(computed_score_data[:current][:grade]).to eq 125.0
+              end
+            end
+          end
+
           describe "persisting score data" do
             let(:calculator) { GradeCalculator.new([@user.id], @course.id, ignore_muted: true) }
             let(:enrollment) { Enrollment.find_by!(user: @user, course: @course) }

spec/models/assignment_spec.rb

@@ -44,8 +44,8 @@ describe Assignment do
   it { is_expected.not_to validate_presence_of(:final_grader) }
 
   it "should create a new instance given valid attributes" do
-    course = @course.assignments.create!(assignment_valid_attributes)
-    expect(course).to be_valid
+    assignment = @course.assignments.create!(assignment_valid_attributes)
+    expect(assignment).to be_valid
   end
 
   it "should set the lti_context_id on create" do
@@ -1388,6 +1388,38 @@ describe Assignment do
     end
   end
 
+  describe ".preload_unposted_anonymous_submissions" do
+    it "preloads unposted anonymous submissions for an assignment" do
+      assignment = @course.assignments.create!(assignment_valid_attributes.merge(anonymous_grading: true))
+      expect(Assignment).to receive(:where).once.and_call_original
+      expect { Assignment.preload_unposted_anonymous_submissions([assignment]) }.to change {
+        assignment.unposted_anonymous_submissions
+      }.from(nil).to(true)
+    end
+
+    it "preloads if some assignments have the attribute preloaded but others do not" do
+      assignment = @course.assignments.create!(assignment_valid_attributes.merge(anonymous_grading: true))
+      other_assignment = @course.assignments.create!(assignment_valid_attributes.merge(anonymous_grading: true))
+      assignment.unposted_anonymous_submissions = true
+      expect(Assignment).to receive(:where).once.and_call_original
+      Assignment.preload_unposted_anonymous_submissions([assignment, other_assignment])
+    end
+
+    it "does not attempt to preload if all assignments already have the attribute preloaded" do
+      assignment = @course.assignments.create!(assignment_valid_attributes.merge(anonymous_grading: true))
+      other_assignment = @course.assignments.create!(assignment_valid_attributes.merge(anonymous_grading: true))
+      assignment.unposted_anonymous_submissions = true
+      other_assignment.unposted_anonymous_submissions = true
+      expect(Assignment).not_to receive(:where)
+      Assignment.preload_unposted_anonymous_submissions([assignment, other_assignment])
+    end
+
+    it "does not attempt to preload if given an empty array" do
+      expect(Assignment).not_to receive(:where)
+      Assignment.preload_unposted_anonymous_submissions([])
+    end
+  end
+
   describe "scope: importing_for_too_long" do
     subject { described_class.importing_for_too_long }
 

spec/models/lti/lti_outbound_adapter_spec.rb

@@ -361,6 +361,7 @@ describe Lti::LtiOutboundAdapter do
           url: tool.url
         )
       )
+      allow_any_instance_of(Account).to receive(:feature_enabled?).and_call_original
     end
 
     it 'builds the expected encrypted JWT with the correct course data' do