New Exporter::NonContactAuthors class

This class is capable of quering a list of people from authors of given posts that are non-contacts of a given
user.

lib/diaspora/exporter/non_contact_authors.rb

@@ -0,0 +1,36 @@
+module Diaspora
+  class Exporter
+    # This class is capable of quering a list of people from authors of given posts that are non-contacts of a given
+    # user.
+    class NonContactAuthors
+      # @param posts [Post::ActiveRecord_Relation] posts that we fetch authors from to make authors list
+      # @param user [User] a user we fetch a contact list from
+      def initialize(posts, user)
+        @posts = posts
+        @user = user
+      end
+
+      # Create a request of non-contact authors of the posts for the user
+      # @return [Post::ActiveRecord_Relation]
+      def query
+        Person.where(id: non_contact_authors_ids)
+      end
+
+      private
+
+      def non_contact_authors_ids
+        posts_authors_ids - contacts_ids
+      end
+
+      def posts_authors_ids
+        posts.pluck(:author_id).uniq
+      end
+
+      def contacts_ids
+        user.contacts.pluck(:person_id)
+      end
+
+      attr_reader :posts, :user
+    end
+  end
+end

spec/lib/diaspora/exporter/non_contact_authors_spec.rb

@@ -0,0 +1,25 @@
+describe Diaspora::Exporter::NonContactAuthors do
+  describe "#query" do
+    let(:user) { FactoryGirl.create(:user_with_aspect) }
+    let(:post) { FactoryGirl.create(:status_message) }
+    let(:instance) {
+      Diaspora::Exporter::NonContactAuthors.new(Post.where(id: post.id), user)
+    }
+
+    context "without contact relationship" do
+      it "includes post author to the result set" do
+        expect(instance.query).to eq([post.author])
+      end
+    end
+
+    context "with contact relationship" do
+      before do
+        user.share_with(post.author, user.aspects.first)
+      end
+
+      it "doesn't include post author to the result set" do
+        expect(instance.query).to be_empty
+      end
+    end
+  end
+end