Sort templates when fetching them

Used to rely on the underlying filesystem to sort the entries, now its
forced to be sorted on the name of the template.

changelogs/unreleased/zj-sort-templates.yml

+---
+title: Sort templates in the dropdown
+merge_request:
+author:
+type: fixed

lib/gitlab/template/base_template.rb

@@ -18,6 +18,10 @@ module Gitlab
         { name: name, content: content }
       end
 
+      def <=>(other)
+        name <=> other.name
+      end
+
       class << self
         def all(project = nil)
           if categories.any?
@@ -58,7 +62,7 @@ module Gitlab
           directory = category_directory(category)
           files = finder(project).list_files_for(directory)
 
-          files.map { |f| new(f, project) }
+          files.map { |f| new(f, project) }.sort
         end
 
         def category_directory(category)

spec/lib/gitlab/template/gitlab_ci_yml_template_spec.rb

@@ -30,6 +30,14 @@ describe Gitlab::Template::GitlabCiYmlTemplate do
     end
   end
 
+  describe '.by_category' do
+    it 'returns sorted results' do
+      result = described_class.by_category('General')
+
+      expect(result).to eq(result.sort)
+    end
+  end
+
   describe '#content' do
     it 'loads the full file' do
       gitignore = subject.new(Rails.root.join('vendor/gitlab-ci-yml/Ruby.gitlab-ci.yml'))
@@ -38,4 +46,14 @@ describe Gitlab::Template::GitlabCiYmlTemplate do
       expect(gitignore.content).to start_with('#')
     end
   end
+
+  describe '#<=>' do
+    it 'sorts lexicographically' do
+      one = described_class.new('a.gitlab-ci.yml')
+      other = described_class.new('z.gitlab-ci.yml')
+
+      expect(one.<=>(other)).to be(-1)
+      expect([other, one].sort).to eq([one, other])
+    end
+  end
 end