Add writable_clasification_tags

https://bugzilla.redhat.com/show_bug.cgi?id=1467805
https://bugzilla.redhat.com/show_bug.cgi?id=1519457

app/models/classification.rb

@@ -35,6 +35,8 @@ class Classification < ApplicationRecord
   scope :is_category, -> { where(:parent_id => 0) }
   scope :is_entry,    -> { where.not(:parent_id => 0) }
 
+  scope :with_writable_parents, -> { includes(:parent).where(:parents_classifications => { :read_only => false}) }
+
   DEFAULT_NAMESPACE = "/managed"
 
   default_value_for :read_only,    false

lib/extensions/ar_taggable.rb

@@ -25,6 +25,10 @@ def self.split_tag_names(tags, separator)
     end.map(&:strip).uniq
   end
 
+  def writable_classification_tags
+    tags.merge(Classification.with_writable_parents)
+  end
+
   module ClassMethods
     # @option options :cat [String|nil] optional category for the tags
     # @option options :ns  [String|nil] optional namespace for the tags

spec/lib/extensions/ar_taggable_spec.rb

@@ -16,6 +16,25 @@
     @vm4.tag_add("bos phi blt")
   end
 
+  describe '#writable_classification_tags' do
+    let(:parent_classification) { FactoryGirl.create(:classification, :description => "Environment", :name => "environment", :read_only => false) }
+    let(:classification)        { FactoryGirl.create(:classification, :name => "prod", :description => "Production", :parent => parent_classification, :read_only => true) }
+
+    before do
+      classification.assign_entry_to(@vm1)
+    end
+
+    it "returns only tags as they would be entered in UI by user(edit tags screen)" do
+      expect(@vm1.tags.count).to eq(4)
+      expect(@vm1.writable_classification_tags.count).to eq(1)
+      expect(@vm1.writable_classification_tags.first.name).to eq('/managed/environment/prod')
+      expect(@vm1.writable_classification_tags.first).to be_kind_of(Tag)
+
+      expect(@vm3.writable_classification_tags.count).to eq(0)
+      expect(@vm3.tags.count).to eq(3)
+    end
+  end
+
   context ".find_tagged_with" do
     it ":any" do
       found = Host.find_tagged_with(:any => "red black", :ns => "/test/tags")