Add Assignment#duplicate_of relation

This commit updates Assignment#duplicate to store a reference to the
original assignment on the duplicated assignment. Both the original
assignment and the new assignment's lti_resource_link_id are included
in the `assignment_created` live event emitted when the new assignment
is saved.

This allows LTI tools listening for Canvas live events to identify when
an assignment has been duplicated, and duplicate their own data
accordingly.

Closes QUIZ-3749

Test plan:

- Set up live events and tail the kinesis stream as per the instructions
  in doc/live_events.md
- Create an LTI assignment
- An `assignment_created` live event containing this assignment's
  lti_resource_link_id should appear in the kinesis log. Make a note of
  this lti_resource_link_id
- Duplicate this assignment by clicking the "kebab" menu and clicking
  "Duplicate"
- Check that another `assignment_created` live event appears in the
  kinesis log, containing both the original assignment's
  lti_resource_link_id and the new assignment's lti_resource_link_id

Change-Id: I64bdb9a2132e58c4e7be0ab7687c2c819a3587fd
Reviewed-on: https://gerrit.instructure.com/140877
Tested-by: Jenkins
QA-Review: Michael Hargiss <mhargiss@instructure.com>
Reviewed-by: Jeff Belser <jbelser@instructure.com>
Product-Review: Michael Hargiss <mhargiss@instructure.com>

app/models/assignment.rb

@@ -72,6 +72,9 @@ class Assignment < ActiveRecord::Base
   belongs_to :grading_standard
   belongs_to :group_category
 
+  belongs_to :duplicate_of, class_name: 'Assignment', optional: true, inverse_of: :duplicates
+  has_many :duplicates, class_name: 'Assignment', inverse_of: :duplicate_of, foreign_key: 'duplicate_of_id'
+
   has_many :assignment_configuration_tool_lookups, dependent: :delete_all
   has_many :tool_settings_context_external_tools, through: :assignment_configuration_tool_lookups, source: :tool, source_type: 'ContextExternalTool'
   has_many :line_items, inverse_of: :assignment, class_name: 'Lti::LineItem', dependent: :destroy
@@ -199,6 +202,13 @@ class Assignment < ActiveRecord::Base
     # Learning outcome alignments seem to get copied magically, possibly
     # through the rubric
     result.rubric_association = self.rubric_association.clone
+
+    # Link the duplicated assignment to this assignment
+    result.duplicate_of = self
+
+    # If this assignment uses an external tool, duplicate that too
+    result.external_tool_tag = self.external_tool_tag&.dup
+
     result
   end
 
@@ -2580,6 +2590,11 @@ class Assignment < ActiveRecord::Base
     @skip_due_date_validation = true
   end
 
+  def lti_resource_link_id
+    return nil if external_tool_tag.blank?
+    ContextExternalTool.opaque_identifier_for(external_tool_tag, shard)
+  end
+
   private
 
   def due_date_ok?

app/models/exporters/quizzes2_exporter.rb

@@ -35,12 +35,9 @@ module Exporters
     end
 
     def build_assignment_payload
-      external_tool_tag = @assignment.external_tool_tag
       {
         assignment: {
-          resource_link_id: ContextExternalTool.opaque_identifier_for(
-            external_tool_tag, @assignment.shard
-          ),
+          resource_link_id: @assignment.lti_resource_link_id,
           title: @quiz.title,
           context_title: @quiz.context.name,
           course_uuid: @course.uuid

db/migrate/20180213235146_add_duplicate_of_to_assignments.rb

@@ -0,0 +1,27 @@
+#
+# Copyright (C) 2018 - present 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/>.
+#
+
+class AddDuplicateOfToAssignments < ActiveRecord::Migration[5.0]
+  tag :predeploy
+  disable_ddl_transaction!
+
+  def change
+    add_reference :assignments, :duplicate_of, type: :bigint, foreign_key: { to_table: :assignments }, index: false
+    add_index :assignments, :duplicate_of_id, where: 'duplicate_of_id IS NOT NULL', algorithm: :concurrently
+  end
+end

lib/api/v1/assignment.rb

@@ -192,7 +192,7 @@ module Api::V1::Assignment
       hash['external_tool_tag_attributes'] = {
         'url' => external_tool_tag.url,
         'new_tab' => external_tool_tag.new_tab,
-        'resource_link_id' => ContextExternalTool.opaque_identifier_for(external_tool_tag, assignment.shard)
+        'resource_link_id' => assignment.lti_resource_link_id
       }
       hash['url'] = sessionless_launch_url(@context,
                                            :launch_type => 'assessment',

lib/canvas/live_events.rb

@@ -172,7 +172,9 @@ module Canvas::LiveEvents
       lock_at: assignment.lock_at,
       updated_at: assignment.updated_at,
       points_possible: assignment.points_possible,
-      lti_assignment_id: assignment.lti_context_id
+      lti_assignment_id: assignment.lti_context_id,
+      lti_resource_link_id: assignment.lti_resource_link_id,
+      lti_resource_link_id_duplicated_from: assignment.duplicate_of&.lti_resource_link_id
     }
   end
 

spec/lib/canvas/live_events_spec.rb

@@ -502,7 +502,9 @@ describe Canvas::LiveEvents do
           unlock_at: assignment.unlock_at,
           lock_at: assignment.lock_at,
           points_possible: assignment.points_possible,
-          lti_assignment_id: assignment.lti_context_id
+          lti_assignment_id: assignment.lti_context_id,
+          lti_resource_link_id: assignment.lti_resource_link_id,
+          lti_resource_link_id_duplicated_from: assignment.duplicate_of&.lti_resource_link_id
         })).once
 
       Canvas::LiveEvents.assignment_created(assignment)
@@ -526,7 +528,9 @@ describe Canvas::LiveEvents do
           unlock_at: assignment.unlock_at,
           lock_at: assignment.lock_at,
           points_possible: assignment.points_possible,
-          lti_assignment_id: assignment.lti_context_id
+          lti_assignment_id: assignment.lti_context_id,
+          lti_resource_link_id: assignment.lti_resource_link_id,
+          lti_resource_link_id_duplicated_from: assignment.duplicate_of&.lti_resource_link_id
         })).once
 
       Canvas::LiveEvents.assignment_updated(assignment)

spec/models/assignment_spec.rb

@@ -405,16 +405,29 @@ describe Assignment do
     expect(new_assignment.rubric_association).not_to be_nil
     expect(new_assignment.title).to eq "Wiki Assignment Copy"
     expect(new_assignment.wiki_page.title).to eq "Wiki Assignment Copy"
+    expect(new_assignment.duplicate_of).to eq assignment
     new_assignment.save!
     new_assignment2 = assignment.duplicate
     expect(new_assignment2.title).to eq "Wiki Assignment Copy 2"
     new_assignment2.save!
+    expect(assignment.duplicates).to match_array [new_assignment, new_assignment2]
     # Go back to the first new assignment to test something just ending in
     # "Copy"
     new_assignment3 = new_assignment.duplicate
     expect(new_assignment3.title).to eq "Wiki Assignment Copy 3"
   end
 
+  it "duplicates an assignment's external_tool_tag" do
+    assignment = @course.assignments.create!(
+      submission_types: 'external_tool',
+      external_tool_tag_attributes: { url: 'http://example.com/launch' },
+      **assignment_valid_attributes
+    )
+    new_assignment = assignment.duplicate
+    expect(new_assignment.external_tool_tag).to be_present
+    expect(new_assignment.external_tool_tag.content).to eq(assignment.external_tool_tag.content)
+  end
+
   describe "#representatives" do
     context "individual students" do
       it "sorts by sortable_name" do
@@ -4881,6 +4894,35 @@ describe Assignment do
     end
   end
 
+  describe '#lti_resource_link_id' do
+    subject { assignment.lti_resource_link_id }
+
+    context 'without external tool tag' do
+      let(:assignment) do
+        @course.assignments.create!(assignment_valid_attributes)
+      end
+
+      it { is_expected.to be_nil }
+    end
+
+    context 'with external tool tag' do
+      let(:assignment) do
+        @course.assignments.create!(submission_types: 'external_tool',
+                                    external_tool_tag_attributes: { url: 'http://example.com/launch' },
+                                    **assignment_valid_attributes)
+      end
+
+      it 'calls ContextExternalTool.opaque_identifier_for with the external tool tag and assignment shard' do
+        lti_resource_link_id = SecureRandom.hex
+        expect(ContextExternalTool).to receive(:opaque_identifier_for).with(
+          assignment.external_tool_tag,
+          assignment.shard
+        ).and_return(lti_resource_link_id)
+        expect(assignment.lti_resource_link_id).to eq(lti_resource_link_id)
+      end
+    end
+  end
+
   def setup_assignment_with_group
     assignment_model(:group_category => "Study Groups", :course => @course)
     @group = @a.context.groups.create!(:name => "Study Group 1", :group_category => @a.group_category)