Fixed duplicated issue note email notifications.

Fixes #2560 (closed)

See issue for the details.

Without uniq modified tests were failing with:

     Failure/Error: notification.new_note(note)
       (Notify (class)).note_issue_email(21, 1)
           expected: 1 time with arguments: (21, 1)
           received: 2 times with arguments: (21, 1)
     # /home/bak1an/.rvm/gems/ruby-2.1.6@gitlab/gems/sidekiq-3.3.0/lib/sidekiq/extensions/action_mailer.rb:17:in `public_send'
     # /home/bak1an/.rvm/gems/ruby-2.1.6@gitlab/gems/sidekiq-3.3.0/lib/sidekiq/extensions/action_mailer.rb:17:in `perform'
     # /home/bak1an/.rvm/gems/ruby-2.1.6@gitlab/gems/sidekiq-3.3.0/lib/sidekiq/testing.rb:74:in `block in raw_push'
     # /home/bak1an/.rvm/gems/ruby-2.1.6@gitlab/gems/sidekiq-3.3.0/lib/sidekiq/testing.rb:69:in `each'
     # /home/bak1an/.rvm/gems/ruby-2.1.6@gitlab/gems/sidekiq-3.3.0/lib/sidekiq/testing.rb:69:in `raw_push'
     # /home/bak1an/.rvm/gems/ruby-2.1.6@gitlab/gems/sidekiq-3.3.0/lib/sidekiq/client.rb:68:in `push'
     # /home/bak1an/.rvm/gems/ruby-2.1.6@gitlab/gems/sidekiq-3.3.0/lib/sidekiq/worker.rb:85:in `client_push'
     # /home/bak1an/.rvm/gems/ruby-2.1.6@gitlab/gems/sidekiq-3.3.0/lib/sidekiq/extensions/generic_proxy.rb:19:in `method_missing'
     # ./app/services/notification_service.rb:144:in `block in new_note'
     # ./app/services/notification_service.rb:143:in `each'
     # ./app/services/notification_service.rb:143:in `new_note'
     # ./spec/services/notification_service_spec.rb:63:in `block (5 levels) in <top (required)>'

I have also added once to all should_email checks within notification_service_spec.rb since it's probably the correct behavior to notify users only once on the same event. Nothing else failed out of the box but we can keep these assertions for future.

Attaching the screenshot of how the issue looks within my gmail:

Added 23 commits:

• 75cd22bf...d73d2a5e - 22 commits from branch gitlab-org:master
• d0576801 - Fixed duplicated issue note email notifications.

Title changed from Fixed duplicated issue note email notifications. to WIP: Fixed duplicated issue note email notifications.

spec/services/notification_service_spec.rb was changed in master creating 13 conflicts here.

Will resolve these and remove "WIP:".

Added 228 commits:

• d0576801...d2f9a901 - 227 commits from branch gitlab-org:master
• f7bb5eb3 - Fixed duplicated issue note email notifications.

Added 3 commits:

• f7bb5eb3...4294d2cd - 2 commits from branch gitlab-org:master
• caa6851b - Fixed duplicated issue note email notifications.

Title changed from WIP: Fixed duplicated issue note email notifications. to Fixed duplicated issue note email notifications.

Tests are green now.

After rebase updated tests were failing without recipients = recipients.uniq with:

1) NotificationService Notes issue note new_note should be truthy
    Failure/Error: expect(sent_to_user?(user)).to be_truthy
      expected: truthy value
           got: false
    # ./spec/services/notification_service_spec.rb:402:in `should_email'
    # ./spec/services/notification_service_spec.rb:64:in `block (5 levels) in <top (required)>'
    # ./spec/services/notification_service_spec.rb:8:in `block (3 levels) in <top (required)>'
    # /home/bak1an/.rvm/gems/ruby-2.1.6@gitlab/gems/activejob-4.2.4/lib/active_job/test_helper.rb:198:in `perform_enqueued_jobs'
    # ./spec/services/notification_service_spec.rb:7:in `block (2 levels) in <top (required)>'

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Finished in 28.02 seconds (files took 9.22 seconds to load)
23 examples, 1 failure

mentioned in commit e2c57a41

Status changed to merged

Thanks, @bak1an!

mentioned in commit 3e977284