diff --git a/.gitignore b/.gitignore
index 611ea3d9f..9c6100421 100644
--- a/.gitignore
+++ b/.gitignore
@@ -11,3 +11,4 @@ doc
 /.bundle
 /.yardoc
 /coverage
+/external
diff --git a/Gemfile b/Gemfile
index 2c10a4a84..7596be6a2 100644
--- a/Gemfile
+++ b/Gemfile
@@ -19,6 +19,6 @@ group :test do
   gem "webrick"
 
   unless ENV['CI'] == 'spec'
-    gem 'bake-test-external'
+    gem 'bake-test-external', '~> 0.3.3'
   end
 end
diff --git a/config/external.yaml b/config/external.yaml
index dfb0fc67f..7ca421b10 100644
--- a/config/external.yaml
+++ b/config/external.yaml
@@ -11,3 +11,6 @@ roda:
 grape:
   url: https://github.com/ruby-grape/grape
   command: bundle exec rspec --exclude-pattern=spec/integration/**/*_spec.rb
+sinatra:
+  url: https://github.com/sinatra/sinatra
+  command: bundle exec rake test