diff --git a/Gemfile b/Gemfile
index 2fdcec062c4..4bdb5a4986e 100644
--- a/Gemfile
+++ b/Gemfile
@@ -60,6 +60,7 @@ instance_eval File.read local_gemfile if File.exist? local_gemfile
 group :test do
   # FIX: Our test suite isn't ready to run in random order yet
   gem 'minitest', '< 5.3.4'
+  gem 'method_source'
 
   platforms :mri_19 do
     gem 'ruby-prof', '~> 0.11.2'
diff --git a/Gemfile.lock b/Gemfile.lock
index 7c42779a7d1..1139e05aa54 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -134,6 +134,7 @@ GEM
     loofah (2.0.1)
       nokogiri (>= 1.5.9)
     metaclass (0.0.4)
+    method_source (0.8.2)
     mime-types (2.4.3)
     mini_portile (0.6.2)
     minitest (5.3.3)
@@ -260,6 +261,7 @@ DEPENDENCIES
   json
   kindlerb (= 0.1.1)
   mail!
+  method_source
   minitest (< 5.3.4)
   mocha (~> 0.14)
   mysql (>= 2.9.0)