Add SnippetRepositoryStorageMove entity

In this commit we create the entity that will be used later
on in a follow-up by some new API REST endpoints.

lib/api/entities/basic_repository_storage_move.rb

+# frozen_string_literal: true
+
+module API
+  module Entities
+    class BasicRepositoryStorageMove < Grape::Entity
+      expose :id
+      expose :created_at
+      expose :human_state_name, as: :state
+      expose :source_storage_name
+      expose :destination_storage_name
+    end
+  end
+end

lib/api/entities/basic_snippet.rb

+# frozen_string_literal: true
+
+module API
+  module Entities
+    class BasicSnippet < Grape::Entity
+      expose :id, :title, :description, :visibility
+      expose :updated_at, :created_at
+      expose :project_id
+      expose :web_url do |snippet|
+        Gitlab::UrlBuilder.build(snippet)
+      end
+      expose :raw_url do |snippet|
+        Gitlab::UrlBuilder.build(snippet, raw: true)
+      end
+      expose :ssh_url_to_repo, :http_url_to_repo, if: ->(snippet) { snippet.repository_exists? }
+    end
+  end
+end

lib/api/entities/project_repository_storage_move.rb

@@ -2,12 +2,7 @@
 
 module API
   module Entities
-    class ProjectRepositoryStorageMove < Grape::Entity
-      expose :id
-      expose :created_at
-      expose :human_state_name, as: :state
-      expose :source_storage_name
-      expose :destination_storage_name
+    class ProjectRepositoryStorageMove < BasicRepositoryStorageMove
       expose :project, using: Entities::ProjectIdentity
     end
   end

lib/api/entities/snippet.rb

@@ -2,18 +2,8 @@
 
 module API
   module Entities
-    class Snippet < Grape::Entity
-      expose :id, :title, :description, :visibility
+    class Snippet < BasicSnippet
       expose :author, using: Entities::UserBasic
-      expose :updated_at, :created_at
-      expose :project_id
-      expose :web_url do |snippet|
-        Gitlab::UrlBuilder.build(snippet)
-      end
-      expose :raw_url do |snippet|
-        Gitlab::UrlBuilder.build(snippet, raw: true)
-      end
-      expose :ssh_url_to_repo, :http_url_to_repo, if: ->(snippet) { snippet.repository_exists? }
       expose :file_name do |snippet|
         snippet.file_name_on_repo || snippet.file_name
       end

lib/api/entities/snippet_repository_storage_move.rb

+# frozen_string_literal: true
+
+module API
+  module Entities
+    class SnippetRepositoryStorageMove < BasicRepositoryStorageMove
+      expose :snippet, using: Entities::BasicSnippet
+    end
+  end
+end

spec/lib/api/entities/snippet_repository_storage_move_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe API::Entities::SnippetRepositoryStorageMove do
+  describe '#as_json' do
+    subject { entity.as_json }
+
+    let(:default_storage) { 'default' }
+    let(:second_storage) { 'test_second_storage' }
+    let(:storage_move) { create(:snippet_repository_storage_move, :scheduled, destination_storage_name: second_storage) }
+    let(:entity) { described_class.new(storage_move) }
+
+    it 'includes basic fields' do
+      allow(Gitlab.config.repositories.storages).to receive(:keys).and_return(%W[#{default_storage} #{second_storage}])
+
+      is_expected.to include(
+        state: 'scheduled',
+        source_storage_name: default_storage,
+        destination_storage_name: second_storage,
+        snippet: a_kind_of(Hash)
+      )
+    end
+  end
+end