select_provisional_grade endpoint

test plan:
 1. have a moderated assignment and at least one student
    selected for moderation
 2. as two different TAs, give provisional grades to a student
 3. use the "list gradeable students" endpoint with
    include[]=provisional_grades to see the provisional_grade_ids
    for the two grades
    (see https://gerrit.instructure.com/#/c/63092/)
 4. use the "select provisional grade" endpoint to select one
    of these provisional grades for publishing
    PUT /courses/X/assignments/Y/select_provisional_grade/Z
    where Z is a provisional_grade_id from step 3
 5. the response from step 4 should be a simple json object
    repeating the course, assignment, and provisional grade ids
 6. redo the endpoint from step 3 to confirm the provisional
    grade was actually selected (a selected_provisional_grade_id
    will be returned along with the student whose grade was
    selected)

fixes CNVS-23132

Change-Id: Ic05bce9685f6b246ee8e484523d51a9a014fb517
Reviewed-on: https://gerrit.instructure.com/63356
QA-Review: Clare Strong <clare@instructure.com>
Reviewed-by: Dan Minkevitch <dan@instructure.com>
Tested-by: Jenkins
Product-Review: Jeremy Stanley <jeremy@instructure.com>

app/controllers/submissions_api_controller.rb

@@ -755,6 +755,30 @@ class SubmissionsApiController < ApplicationController
     end
   end
 
+  # undocumented @API Select provisional grade
+  #
+  # Choose which provisional grade the student should receive for a submission.
+  # The caller must have :moderate_grades rights.
+  #
+  # @example_response
+  #   {
+  #     "assignment_id": 867,
+  #     "student_id": 5309,
+  #     "selected_provisional_grade_id": 53669
+  #   }
+  #
+  def select_provisional_grade
+    if authorized_action(@context, @current_user, :moderate_grades)
+      assignment = @context.assignments.active.find(params[:assignment_id])
+      pg = assignment.provisional_grades.find(params[:provisional_grade_id])
+      selection = assignment.moderated_grading_selections.where(student_id: pg.submission.user_id).first
+      return render :json => { :message => 'student not in moderation set' }, :status => :bad_request unless selection
+      selection.provisional_grade = pg
+      selection.save!
+      render :json => selection.as_json(:include_root => false, :only => %w(assignment_id student_id selected_provisional_grade_id))
+    end
+  end
+
   # @API Grade or comment on multiple submissions
   #
   # Update the grading and comments on multiple student's assignment

app/models/assignment.rb

@@ -65,6 +65,7 @@ class Assignment < ActiveRecord::Base
   attr_reader :assignment_changed
 
   has_many :submissions, :dependent => :destroy
+  has_many :provisional_grades, :through => :submissions
   has_many :attachments, :as => :context, :dependent => :destroy
   has_many :assignment_student_visibilities
   has_one :quiz, class_name: 'Quizzes::Quiz'

config/routes.rb

@@ -976,6 +976,7 @@ CanvasRails::Application.routes.draw do
       end
       get "courses/:course_id/assignments/:assignment_id/gradeable_students", action: :gradeable_students, as: "course_assignment_gradeable_students"
       post "courses/:course_id/assignments/:assignment_id/publish_provisional_grades", action: :publish_provisional_grades, as: 'publish_provisional_grades'
+      put "courses/:course_id/assignments/:assignment_id/select_provisional_grade/:provisional_grade_id", action: :select_provisional_grade
     end
 
     post '/courses/:course_id/assignments/:assignment_id/submissions/:user_id/comments/files', action: :create_file, controller: :submission_comments_api

spec/apis/v1/submissions_api_spec.rb

@@ -3395,4 +3395,49 @@ describe 'Submissions API', type: :request do
       end
     end
   end
+
+  describe "select_provisional_grade" do
+    before(:once) do
+      course_with_student :active_all => true
+      ta_in_course :active_all => true
+      @course.root_account.allow_feature! :moderated_grading
+      @course.enable_feature! :moderated_grading
+      @assignment = @course.assignments.build
+      @assignment.moderated_grading = true
+      @assignment.save!
+      subs = @assignment.grade_student @student, :grader => @ta, :score => 0, :provisional => true
+      @pg = subs.first.provisional_grade(@ta)
+      @path = "/api/v1/courses/#{@course.id}/assignments/#{@assignment.id}/select_provisional_grade/#{@pg.id}"
+      @params = { :controller => 'submissions_api', :action => 'select_provisional_grade',
+                  :format => 'json', :course_id => @course.to_param, :assignment_id => @assignment.to_param,
+                  :provisional_grade_id => @pg.to_param }
+    end
+
+    it "should fail if the student isn't in the moderation set" do
+      json = api_call_as_user(@teacher, :put, @path, @params, {}, {}, { :expected_status => 400 })
+      expect(json['message']).to eq 'student not in moderation set'
+    end
+
+    context "with moderation set" do
+      before(:once) do
+        @selection = @assignment.moderated_grading_selections.build
+        @selection.student_id = @student.id
+        @selection.save!
+      end
+
+      it "should require :moderate_grades" do
+        api_call_as_user(@ta, :put, @path, @params, {}, {}, { :expected_status => 401 })
+      end
+
+      it "should select a provisional grade" do
+        json = api_call_as_user(@teacher, :put, @path, @params)
+        expect(json).to eq({
+                             'assignment_id' => @assignment.id,
+                             'student_id' => @student.id,
+                             'selected_provisional_grade_id' => @pg.id
+                           })
+        expect(@selection.reload.provisional_grade).to eq(@pg)
+      end
+    end
+  end
 end