move ungraded count checking to it's own class

fixes CNVS-12392

test plan:
regression test on alerts for ungraded assignments

Change-Id: I0ee553666706e91a96b953b1796578b834fd88b7
Reviewed-on: https://gerrit.instructure.com/33284
Reviewed-by: Cody Cutrer <cody@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
QA-Review: Jeremy Putnam <jeremyp@instructure.com>
Product-Review: Simon Williams <simon@instructure.com>

Author: rivernate

app/models/alert.rb

@@ -157,16 +157,7 @@ def self.evaluate_for_course(course, account_alerts, include_user_notes)
       end
     end
     if criterion_types.include? 'UngradedCount'
-      ungraded_counts = course.submissions.
-          group("submissions.user_id").
-          where(:user_id => student_ids).
-          where(Submission.needs_grading_conditions).
-          except(:order).
-          count
-      ungraded_counts.each do |user_id, count|
-        student = data[user_id]
-        student[:ungraded_count] = count
-      end
+      ungraded_count_alert = Alerts::UngradedCount.new(course, student_ids)
     end
     if criterion_types.include? 'UngradedTimespan'
       ungraded_timespans = course.submissions.
@@ -212,7 +203,7 @@ def self.evaluate_for_course(course, account_alerts, include_user_notes)
               break
             end
           when 'UngradedCount'
-            if (user_data[:ungraded_count].to_i < criterion.threshold.to_i)
+            if ungraded_count_alert.should_not_receive_message?(user_id, criterion.threshold.to_i)
               matches = false
               break
             end

app/models/alerts/ungraded_count.rb

@@ -0,0 +1,22 @@
+module Alerts
+  class UngradedCount
+
+    def initialize(course, student_ids)
+      @ungraded_count_for_student = {}
+      ungraded_counts = course.submissions.
+        group("submissions.user_id").
+        where(:user_id => student_ids).
+        where(Submission.needs_grading_conditions).
+        except(:order).
+        count
+      ungraded_counts.each do |user_id, count|
+        @ungraded_count_for_student[user_id] = count
+      end
+    end
+
+    def should_not_receive_message?(user_id, threshold)
+      (@ungraded_count_for_student[user_id].to_i < threshold)
+    end
+
+  end
+end

spec/models/alerts/ungraded_count_spec.rb

@@ -0,0 +1,79 @@
+#
+# Copyright (C) 2014 Instructure, Inc.
+#
+# This file is part of Canvas.
+#
+# Canvas is free software: you can redistribute it and/or modify it under
+# the terms of the GNU Affero General Public License as published by the Free
+# Software Foundation, version 3 of the License.
+#
+# Canvas is distributed in the hope that it will be useful, but WITHOUT ANY
+# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+# A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Affero General Public License along
+# with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+
+require File.expand_path(File.dirname(__FILE__) + '../../../spec_helper.rb')
+
+module Alerts
+  describe Alerts::UngradedCount do
+
+    describe "#should_not_receive_message?" do
+      before(:each) do
+        course_with_teacher(:active_all => 1)
+        @teacher = @user
+        @user = nil
+        student_in_course(:active_all => 1)
+        @assignment = @course.assignments.new(:title => "some assignment")
+        @assignment.workflow_state = "published"
+        @assignment.save
+        @opts = {
+          submission_type: 'online_text_entry',
+          body: 'submission body'
+        }
+      end
+
+
+      it 'returns true when the student submissions are below the threshold' do
+
+        @assignment.submit_homework(@user, @opts)
+
+        ungraded_count = Alerts::UngradedCount.new(@course, [@student.id])
+        ungraded_count.should_not_receive_message?(@student.id, 2).should == true
+      end
+
+      it 'returns false when the student submissions are above or equal to the threshold' do
+        second_assignment = @course.assignments.new(:title => "some assignment")
+        second_assignment.workflow_state = "published"
+        second_assignment.save
+
+        @assignment.submit_homework(@user, @opts)
+        second_assignment.submit_homework(@user, @opts)
+
+        ungraded_count = Alerts::UngradedCount.new(@course, [@student.id])
+        ungraded_count.should_not_receive_message?(@student.id, 2).should == false
+      end
+
+      it 'returns true when the student has no submissions' do
+        ungraded_count = Alerts::UngradedCount.new(@course, [@student.id])
+        ungraded_count.should_not_receive_message?(@student.id, 2).should == true
+      end
+
+      it 'handles submissions from multiple students' do
+        student_1 = @student
+        course_with_student({course: @course})
+        student_2 = @student
+        @assignment.submit_homework(student_1, @opts)
+        @assignment.submit_homework(student_2, @opts)
+
+        ungraded_count = Alerts::UngradedCount.new(@course, [student_1.id, student_2.id])
+        ungraded_count.should_not_receive_message?(student_1.id, 2).should == true
+      end
+
+    end
+
+  end
+end