diff --git a/spec/bundler/support/artifice/endpoint_500.rb b/spec/bundler/support/artifice/endpoint_500.rb
index d8ab6b65bc..b1ed1964c8 100644
--- a/spec/bundler/support/artifice/endpoint_500.rb
+++ b/spec/bundler/support/artifice/endpoint_500.rb
@@ -2,7 +2,7 @@
 
 require_relative "../path"
 
-$LOAD_PATH.unshift(*Dir[Spec::Path.base_system_gem_path.join("gems/{mustermann,rack,tilt,sinatra,ruby2_keywords}-*/lib")].map(&:to_s))
+$LOAD_PATH.unshift(*Dir[Spec::Path.base_system_gem_path.join("gems/{mustermann,rack,tilt,sinatra,ruby2_keywords,base64}-*/lib")].map(&:to_s))
 
 require "sinatra/base"
 
diff --git a/spec/bundler/support/artifice/helpers/endpoint.rb b/spec/bundler/support/artifice/helpers/endpoint.rb
index be52df6936..83ba1be0fc 100644
--- a/spec/bundler/support/artifice/helpers/endpoint.rb
+++ b/spec/bundler/support/artifice/helpers/endpoint.rb
@@ -2,7 +2,7 @@
 
 require_relative "../../path"
 
-$LOAD_PATH.unshift(*Dir[Spec::Path.base_system_gem_path.join("gems/{mustermann,rack,tilt,sinatra,ruby2_keywords}-*/lib")].map(&:to_s))
+$LOAD_PATH.unshift(*Dir[Spec::Path.base_system_gem_path.join("gems/{mustermann,rack,tilt,sinatra,ruby2_keywords,base64}-*/lib")].map(&:to_s))
 
 require "sinatra/base"
 
diff --git a/spec/bundler/support/artifice/windows.rb b/spec/bundler/support/artifice/windows.rb
index 4d90e0a426..fea991c071 100644
--- a/spec/bundler/support/artifice/windows.rb
+++ b/spec/bundler/support/artifice/windows.rb
@@ -2,7 +2,7 @@
 
 require_relative "../path"
 
-$LOAD_PATH.unshift(*Dir[Spec::Path.base_system_gem_path.join("gems/{mustermann,rack,tilt,sinatra,ruby2_keywords}-*/lib")].map(&:to_s))
+$LOAD_PATH.unshift(*Dir[Spec::Path.base_system_gem_path.join("gems/{mustermann,rack,tilt,sinatra,ruby2_keywords,base64}-*/lib")].map(&:to_s))
 
 require "sinatra/base"
 
diff --git a/tool/bundler/test_gems.rb b/tool/bundler/test_gems.rb
index aa1cfd09a5..32cb6b34ee 100644
--- a/tool/bundler/test_gems.rb
+++ b/tool/bundler/test_gems.rb
@@ -3,6 +3,7 @@
 source "https://rubygems.org"
 
 gem "rack", "~> 2.0"
+gem "base64"
 gem "webrick", "1.7.0"
 gem "rack-test", "~> 1.1"
 gem "compact_index", "~> 0.15.0"