handle 0 point assignments in datafixups

closes EVAL-4564
flag=none

Test Plan:
- specs pass

Change-Id: I33a4eed7aa5efa6da2368df949230e33e9bd6f46
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/356633
Reviewed-by: Kai Bjorkman <kbjorkman@instructure.com>
QA-Review: Kai Bjorkman <kbjorkman@instructure.com>
Tested-by: Service Cloud Jenkins <svc.cloudjenkins@instructure.com>
Product-Review: Cameron Ray <cameron.ray@instructure.com>

lib/data_fixup/regrade_points_based_scheme_assignments.rb

@@ -45,7 +45,7 @@ class DataFixup::RegradePointsBasedSchemeAssignments
     submissions_with_grades = Submission.where.not(grade: nil).where(assignment_id: assignments.select(:id))
     submissions_with_grades.preload(assignment: [:grading_standard, { context: :grading_standard }]).find_in_batches(batch_size: 1000) do |submissions_batch|
       batched_updates = submissions_batch.each_with_object([]) do |submission, acc|
-        new_grade = submission.assignment.score_to_grade(submission.score)
+        new_grade = submission.assignment.score_to_grade(submission.score, submission.grade)
         grade_has_changed = new_grade != submission.grade || new_grade != submission.published_grade
         if grade_has_changed
           acc << submission.attributes.merge("grade" => new_grade, "published_grade" => new_grade, "updated_at" => current_time)

lib/data_fixup/regrade_versions_for_points_based_scheme_assignments.rb

@@ -70,7 +70,7 @@ class DataFixup::RegradeVersionsForPointsBasedSchemeAssignments
       model = version.model
       next unless model.grade.present?
 
-      new_grade = version.versionable.assignment.score_to_grade(model.score)
+      new_grade = version.versionable.assignment.score_to_grade(model.score, model.grade)
       grade_has_changed = new_grade != model.grade || new_grade != model.published_grade
       next unless grade_has_changed
 

spec/lib/data_fixup/regrade_points_based_scheme_assignments_spec.rb

@@ -60,4 +60,13 @@ describe DataFixup::RegradePointsBasedSchemeAssignments do
     }
     expect(@submission3.reload.published_grade).to eq("A")
   end
+
+  it "handles 0 point assignments using points-based grading standards" do
+    @submission1.assignment.update!(points_possible: 0)
+    @submission1.assignment.grade_student(@student, grade: "B", grader: @teacher)
+    expect { DataFixup::RegradePointsBasedSchemeAssignments.run }.not_to change {
+      @submission1.reload.grade
+    }.from("B")
+    expect(@submission1.reload.published_grade).to eq("B")
+  end
 end

spec/lib/data_fixup/regrade_versions_for_points_based_scheme_assignments_spec.rb

@@ -82,4 +82,13 @@ describe DataFixup::RegradeVersionsForPointsBasedSchemeAssignments do
     }
     expect(@submission3.reload.versions.first.model.published_grade).to eq("A")
   end
+
+  it "handles 0 point assignments using points-based grading standards" do
+    @submission1.assignment.update!(points_possible: 0)
+    @submission1.assignment.grade_student(@student, grade: "B", grader: @teacher)
+    expect { DataFixup::RegradeVersionsForPointsBasedSchemeAssignments.run }.not_to change {
+      @submission1.reload.versions.take.model.grade
+    }.from("B")
+    expect(@submission1.reload.versions.take.model.published_grade).to eq("B")
+  end
 end