username-removed-133717
--- a/app/services/notification_service.rb
+++ b/app/services/notification_service.rb

 def reassign_resource_email(target, project, current_user, method)
   assignee_id_was = previous_record(target, "assignee_id")
-   recipients = build_recipients(target, project, current_user)
+   previous_assignee = User.find(assignee_id_was)
--- a/app/services/notification_service.rb
+++ b/app/services/notification_service.rb
   end
 end

- def build_recipients(target, project, current_user)
+ def build_recipients(target, project, current_user, previous_records = nil )
   recipients = target.participants(current_user)
+   recipients.concat(previous_records).compact.uniq if previous_records
--- a/spec/services/issues/update_service_spec.rb
+++ b/spec/services/issues/update_service_spec.rb
     it { expect(@issue.labels.count).to eq(1) }
     it { expect(@issue.labels.first.title).to eq('Bug') }

-     it 'should send email to user2 about assign of new issue' do
-       email = ActionMailer::Base.deliveries.last
-       expect(email.to.first).to eq(user2.email)
+     it 'should send email to user2 about assign of new issue and email to user about issue unassignment' do
+       deliveries =  ActionMailer::Base.deliveries
+       email = deliveries.last
+       recipients = deliveries.map(&:to).uniq.flatten
+       expect(recipients.last(2)).to include(user.email,user2.email)