Send `watcher set` emails only when said watcher allows email notifications.

app/models/watcher_notification_mailer.rb

@@ -30,6 +30,10 @@
 class WatcherNotificationMailer
   class << self
     def handle_watcher(watcher, watcher_setter)
+      # We only handle this watcher setting if associated user wants to be notified
+      # about it.
+      return unless watcher.user.notify_about?(watcher)
+
       unless other_jobs_queued?(watcher.watchable)
         job = DeliverWatcherNotificationJob.new(watcher.id, watcher.user.id, watcher_setter.id)
         Delayed::Job.enqueue job

app/models/work_package.rb

@@ -427,7 +427,7 @@ class WorkPackage < ActiveRecord::Base
   end
 
   # TODO: move into Business Object and rename to update
-  # update for now is a private method defined by AR
+  # update for now is a public method defined by AR
   def update_by!(user, attributes)
     attributes = attributes.dup
     raw_attachments = attributes.delete(:attachments)

spec/models/watcher_notification_mailer_spec.rb

@@ -0,0 +1,76 @@
+#-- encoding: UTF-8
+#-- copyright
+# OpenProject is a project management system.
+# Copyright (C) 2012-2015 the OpenProject Foundation (OPF)
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License version 3.
+#
+# OpenProject is a fork of ChiliProject, which is a fork of Redmine. The copyright follows:
+# Copyright (C) 2006-2013 Jean-Philippe Lang
+# Copyright (C) 2010-2013 the ChiliProject Team
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+#
+# See doc/COPYRIGHT.rdoc for more details.
+#++
+require 'spec_helper'
+
+describe WatcherNotificationMailer do
+  def call_listener(watcher, watcher_setter)
+    described_class.handle_watcher(watcher, watcher_setter)
+  end
+
+  before do
+    # make sure no other calls are made due to WP creation/update
+    allow(OpenProject::Notifications).to receive(:send) # ... and do nothing
+
+    allow(Delayed::Job).to receive(:enqueue)
+  end
+
+  describe 'watcher setup' do
+    let(:project)       { FactoryGirl.create(:project) }
+    let(:work_package)  { FactoryGirl.create(:work_package, project: project) }
+
+    let(:watcher_setter) do
+      FactoryGirl.create(:user,
+                        mail_notification: 'all',
+                        member_in_project: project)
+    end
+
+    let(:watcher) do
+      FactoryGirl.create(:watcher, user: FactoryGirl.create(:user,
+                                          mail_notification: 'all',
+                                          member_in_project: project),
+                                  watchable: work_package)
+    end
+
+    context 'watcher_added and user wants to be notified' do
+      it 'notifies the watcher' do
+        expect(Delayed::Job).to receive(:enqueue)
+        call_listener(watcher, watcher_setter)
+      end
+    end
+
+    context 'watcher_added and user does NOT want to be notified' do
+      it 'does not notify the watcher' do
+        allow(watcher.user).to receive(:notify_about?).with(watcher).and_return(false)
+        expect(Delayed::Job).not_to receive(:enqueue)
+        call_listener(watcher, watcher_setter)
+      end
+    end
+  end
+end
+