Add tests and refactor middleware

config/initializers/etag_caching.rb

@@ -2,4 +2,3 @@
 # in the middleware stack, because it tracks events with
 # GitLab Performance Monitoring
 Rails.application.config.middleware.use(Gitlab::EtagCaching::Middleware)
-Rails.application.config.middleware.use(Gitlab::Jira::Middleware)

config/initializers/jira.rb

+# Treats JIRA DVCS user agent requests in order to be successfully handled
+# by our API.
+Rails.application.config.middleware.use(Gitlab::Jira::Middleware)

lib/gitlab/jira/middleware.rb

@@ -6,12 +6,16 @@ module Gitlab
       end
 
       def call(env)
-        return @app.call(env) unless /JIRA DVCS Connector/.match(env['HTTP_USER_AGENT'])
-
-        env['HTTP_AUTHORIZATION'] = env['HTTP_AUTHORIZATION'].sub('token', 'Bearer')
+        env['HTTP_AUTHORIZATION'].sub!('token', 'Bearer') if jira_dvcs_connector?(env)
 
         @app.call(env)
       end
+
+      private
+
+      def jira_dvcs_connector?(env)
+        /JIRA DVCS Connector/.match(env['HTTP_USER_AGENT'])
+      end
     end
   end
 end

spec/lib/gitlab/jira/middleware_spec.rb

+require 'spec_helper'
+
+describe Gitlab::Jira::Middleware do
+  let(:app) { double(:app) }
+  let(:middleware) { described_class.new(app) }
+
+  describe '#call' do
+    it 'adjusts HTTP_AUTHORIZATION env when request from JIRA DVCS user agent' do
+      user_agent = 'JIRA DVCS Connector Vertigo/5.0.0-D20170810T012915'
+
+      expect(app).to receive(:call).with('HTTP_USER_AGENT' => user_agent,
+                                         'HTTP_AUTHORIZATION' => 'Bearer hash-123')
+
+      middleware.call('HTTP_USER_AGENT' => user_agent, 'HTTP_AUTHORIZATION' => 'token hash-123')
+    end
+
+    it 'does not change HTTP_AUTHORIZATION env when request is not from JIRA DVCS user agent' do
+      env = { 'HTTP_USER_AGENT' => 'Mozilla/5.0', 'HTTP_AUTHORIZATION' => 'token hash-123' }
+
+      expect(app).to receive(:call).with(env)
+
+      middleware.call(env)
+    end
+  end
+end