Add a variable expansions iso8601

Canvas.assignment.unlockAt.iso8601 Canvas.assignment.lockAt.iso8601 Canvas.assignment.dueAt.iso8601

fixes PLAT-1211

test-plan:
install the test tool with Canvas.assignment.unlockAt.iso8601 Canvas.assignment.lockAt.iso8601 Canvas.assignment.dueAt.iso8601 setup as a custom variable
launch the tool
it should return back the above date varibles in iso8601 format.

Change-Id: I6a816e8318cb70d50a0cf39f2138f4e395f39676
Reviewed-on: https://gerrit.instructure.com/61806
Tested-by: Jenkins
Reviewed-by: Nathan Mills <nathanm@instructure.com>
QA-Review: August Thornton <august@instructure.com>
Product-Review: Josh Orr <jgorr@instructure.com>

lib/lti/variable_expander.rb

@@ -289,19 +289,33 @@ module Lti
     register_expansion 'Canvas.assignment.pointsPossible', [],
                        -> { @assignment.points_possible },
                        ASSIGNMENT_GUARD
-
+    #deprecated in favor of ISO8601
     register_expansion 'Canvas.assignment.unlockAt', [],
                        -> { @assignment.unlock_at },
                        ASSIGNMENT_GUARD
 
+    #deprecated in favor of ISO8601
     register_expansion 'Canvas.assignment.lockAt', [],
                        -> { @assignment.lock_at },
                        ASSIGNMENT_GUARD
 
+    #deprecated in favor of ISO8601
     register_expansion 'Canvas.assignment.dueAt', [],
                        -> { @assignment.due_at },
                        ASSIGNMENT_GUARD
 
+    register_expansion 'Canvas.assignment.unlockAt.iso8601', [],
+                       -> { @assignment.unlock_at.utc.iso8601 },
+                       ASSIGNMENT_GUARD
+
+    register_expansion 'Canvas.assignment.lockAt.iso8601', [],
+                       -> { @assignment.lock_at.utc.iso8601 },
+                       ASSIGNMENT_GUARD
+
+    register_expansion 'Canvas.assignment.dueAt.iso8601', [],
+                       -> { @assignment.due_at.utc.iso8601 },
+                       ASSIGNMENT_GUARD
+
     register_expansion 'LtiLink.custom.url', [],
                        -> { @controller.show_lti_tool_settings_url(@tool_setting_link_id) },
                        -> { @tool_setting_link_id }

spec/lib/lti/variable_expander_spec.rb

@@ -17,7 +17,6 @@
 #
 
 require File.expand_path(File.dirname(__FILE__) + '/../../spec_helper')
-
 module Lti
   describe VariableExpander do
     let(:root_account) { Account.new }
@@ -382,6 +381,27 @@ module Lti
           expect(exp_hash[:test]).to eq right_now.to_s
         end
 
+        it 'has substitution for $Canvas.assignment.unlockAt.iso8601' do
+          assignment.stubs(:unlock_at).returns(right_now)
+          exp_hash = {test: '$Canvas.assignment.unlockAt.iso8601'}
+          subject.expand_variables!(exp_hash)
+          expect(exp_hash[:test]).to eq right_now.utc.iso8601.to_s
+        end
+
+        it 'has substitution for $Canvas.assignment.lockAt.iso8601' do
+          assignment.stubs(:lock_at).returns(right_now)
+          exp_hash = {test: '$Canvas.assignment.lockAt.iso8601'}
+          subject.expand_variables!(exp_hash)
+          expect(exp_hash[:test]).to eq right_now.utc.iso8601.to_s
+        end
+
+        it 'has substitution for $Canvas.assignment.dueAt.iso8601' do
+          assignment.stubs(:due_at).returns(right_now)
+          exp_hash = {test: '$Canvas.assignment.dueAt.iso8601'}
+          subject.expand_variables!(exp_hash)
+          expect(exp_hash[:test]).to eq right_now.utc.iso8601.to_s
+        end
+
       end
 
       context 'user is logged in' do