show the correct date/time for the student access report

The report was displaying the AssetUserAccess updated_at, which isn't
always the time of the last access -- #display_name re-saves the record,
for example.

Now AssetUserAccess keeps the last access time in a dedicated
last_access field. Turns out the table already had this column, but it
was unused. So now we're using it.

fixes #6679

test plan:
  * As a student, access some course content -- look at assignments,
    quizzes, pages, the syllabus, etc
  * As a teacher, go to the student roster, select the student, and
    click to view the student access report.
  * Verify that all the last access times are correct (and not just set
    to the current time).

Change-Id: Icef3073e777d191c281a21e8d160ec08201be374
Reviewed-on: https://gerrit.instructure.com/8880
Tested-by: Hudson <hudson@instructure.com>
Reviewed-by: Simon Williams <simon@instructure.com>

app/controllers/application_controller.rb

@@ -698,6 +698,7 @@ class ApplicationController < ActionController::Base
         @access.membership_type ||= @accessed_asset[:membership_type]
         @access.context = @context.is_a?(UserProfile) ? @context.user : @context
         @access.summarized_at = nil
+        @access.last_access = Time.now.utc
         @access.save
         @page_view.asset_user_access_id = @access.id if @page_view
         @page_view_update = true

app/views/context/roster_user_usage.html.erb

@@ -75,7 +75,7 @@
         </td>
         <td class="view_score"><%= access.view_score %></td>
         <td class="participate_score"><%= access.participate_score %></td>
-        <td class="last_viewed time_ago_date"><%= datetime_string(access.updated_at) %></td>
+        <td class="last_viewed time_ago_date"><%= datetime_string(access.last_access) %></td>
       </tr>
     <% end %>
     <tr class="access blank" style="display: none;">
@@ -120,7 +120,7 @@
               var access = data[idx].asset_user_access;
               $access.addClass(access.asset_class_name);
               access.readable_name = access.readable_name || access.display_name || access.asset_code;
-              access.last_viewed = $.parseFromISO(access.updated_at).datetime_formatted;
+              access.last_viewed = $.parseFromISO(access.last_access).datetime_formatted;
               $access.fillTemplateData({data: access});
               $("#usage_report table tbody").append($access.show());
             }

db/migrate/20120221220828_use_asset_user_access_last_access.rb

@@ -0,0 +1,11 @@
+class UseAssetUserAccessLastAccess < ActiveRecord::Migration
+  tag :postdeploy
+
+  def self.up
+    AssetUserAccess.update_all("last_access = updated_at", "last_access is null")
+  end
+
+  def self.down
+    raise ActiveRecord::IrreversibleMigration
+  end
+end

spec/integration/asset_accesses_spec.rb

@@ -40,7 +40,12 @@ describe "user asset accesses" do
     @course.enroll_student(@student).accept
   end
 
+  include ApplicationHelper
+
   it "should record and show user asset accesses" do
+    now = Time.now.utc
+    Time.stubs(:now).returns(now)
+
     assignment = @course.assignments.create(:title => 'Assignment 1')
     assignment.workflow_state = 'active'
     assignment.save!
@@ -56,6 +61,14 @@ describe "user asset accesses" do
     html.css('#usage_report .access.assignment').length.should == 1
     html.css('#usage_report .access.assignment .readable_name').text.strip.should == 'Assignment 1'
     html.css('#usage_report .access.assignment .view_score').text.strip.should == '1'
+    html.css('#usage_report .access.assignment .last_viewed').text.strip.should == datetime_string(now)
+    AssetUserAccess.first(:conditions => { :user_id => @student.id }).last_access.should == now
+
+    now2 = now + 1.hour
+    Time.stubs(:now).returns(now2)
+
+    # make sure that we're not using the uodated_at time as the time of the access
+    AssetUserAccess.update_all({ :updated_at => now2 + 5.hours }, { :user_id => @student.id })
 
     user_session(@student)
     get "/courses/#{@course.id}/assignments/#{assignment.id}"
@@ -68,7 +81,7 @@ describe "user asset accesses" do
     html.css('#usage_report .access.assignment').length.should == 1
     html.css('#usage_report .access.assignment .readable_name').text.strip.should == 'Assignment 1'
     html.css('#usage_report .access.assignment .view_score').text.strip.should == '2'
+    html.css('#usage_report .access.assignment .last_viewed').text.strip.should == datetime_string(now2)
+    AssetUserAccess.first(:conditions => { :user_id => @student.id }).last_access.should == now2
   end
 end
-
-