Add asset_accessed to sessionless launch

closes PLAT-4753

Test Plan:
 - generate a sessionless launch, launch it, see that
   the event is generated on sessionless launch

Change-Id: Ic025da551286edea73e30e48e580b5f3d8d9fe38
Reviewed-on: https://gerrit.instructure.com/207982
Tested-by: Jenkins
QA-Review: Tucker Mcknight <tmcknight@instructure.com>
Reviewed-by: Xander Moffatt <xmoffatt@instructure.com>
Product-Review: Marc Phillips <mphillips@instructure.com>

app/controllers/external_tools_controller.rb

@@ -254,6 +254,9 @@ class ExternalToolsController < ApplicationController
     end
 
     launch_settings = JSON.parse(launch_settings)
+    if tool = ContextExternalTool.find_external_tool(launch_settings['launch_url'], @context)
+      log_asset_access(tool, "external_tools", "external_tools", overwrite: false)
+    end
 
     @lti_launch = Lti::Launch.new
     @lti_launch.params = launch_settings['tool_settings']

spec/controllers/external_tools_controller_spec.rb

@@ -1732,6 +1732,29 @@ describe ExternalToolsController do
     end
   end
 
+  describe '#sessionless_launch' do
+    before do
+      allow(BasicLTI::Sourcedid).to receive(:encryption_secret) {'encryption-secret-5T14NjaTbcYjc4'}
+      allow(BasicLTI::Sourcedid).to receive(:signing_secret) {'signing-secret-vp04BNqApwdwUYPUI'}
+      user_session(@user)
+    end
+
+    it "generates a sessionless launch" do
+      @tool = new_valid_tool(@course)
+
+      get :generate_sessionless_launch, params: {:course_id => @course.id, id: @tool.id}
+
+      expect(response).to be_successful
+
+      json = JSON.parse(response.body.sub(/^while\(1\)\;/, ''))
+      verifier = CGI.parse(URI.parse(json['url']).query)['verifier'].first
+
+      expect(controller).to receive(:log_asset_access).once
+      get :sessionless_launch, params: {:course_id => @course.id, verifier: verifier}
+    end
+
+  end
+
   def opaque_id(asset)
     if asset.respond_to?('lti_context_id')
       Lti::Asset.global_context_id_for(asset)