diff --git a/.gitignore b/.gitignore
index ff6c630..662863d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -13,3 +13,5 @@
 /bundler-1.7.8.gem
 /bundler-1.10.6-specs.tgz
 /bundler-1.10.6.gem
+/bundler-1.12.5-specs.tgz
+/bundler-1.12.5.gem
diff --git a/rubygem-bundler-1.12.5-Fix-test-failures-due-to-Rack-2.x.patch b/rubygem-bundler-1.12.5-Fix-test-failures-due-to-Rack-2.x.patch
new file mode 100644
index 0000000..a890d70
--- /dev/null
+++ b/rubygem-bundler-1.12.5-Fix-test-failures-due-to-Rack-2.x.patch
@@ -0,0 +1,36 @@
+From 28798c7a34bab72347f27372f8efc608c274deb2 Mon Sep 17 00:00:00 2001
+From: Kohei Suzuki <eagletmt@gmail.com>
+Date: Sat, 2 Jul 2016 17:00:44 +0900
+Subject: [PATCH] Fix test failures due to Rack 2.x
+
+- Rack 2.x requires Ruby version >= 2.2.2
+- artifice doesn't support rack 2.x now.
+---
+ spec/support/rubygems_ext.rb | 7 +++++--
+ 1 file changed, 5 insertions(+), 2 deletions(-)
+
+diff --git a/spec/support/rubygems_ext.rb b/spec/support/rubygems_ext.rb
+index 95f596e..862be3d 100644
+--- a/spec/support/rubygems_ext.rb
++++ b/spec/support/rubygems_ext.rb
+@@ -6,7 +6,10 @@ module Spec
+   module Rubygems
+     DEPS = begin
+       deps = {
+-        "fakeweb artifice rack compact_index" => nil,
++        # rack 2.x requires Ruby version >= 2.2.2.
++        # artifice doesn't support rack 2.x now.
++        "rack" => "< 2",
++        "fakeweb artifice compact_index" => nil,
+         "sinatra" => "1.2.7",
+         # Rake version has to be consistent for tests to pass
+         "rake" => "10.0.2",
+@@ -43,7 +46,7 @@ def self.setup
+ 
+     def self.install_gem(name, version = nil)
+       cmd = "gem install #{name} --no-rdoc --no-ri"
+-      cmd += " --version #{version}" if version
++      cmd += " --version '#{version}'" if version
+       system(cmd) || raise("Installing gem #{name} for the tests to use failed!")
+     end
+ 
diff --git a/sources b/sources
index 0a348e6..24ce587 100644
--- a/sources
+++ b/sources
@@ -1,2 +1,2 @@
-74cee91c77402d8938e32ee0866c7700  bundler-1.10.6-specs.tgz
-e637c15440d29a7fad933d0de5be351a  bundler-1.10.6.gem
+4973632491629d349e6bc390444ac6d5  bundler-1.12.5-specs.tgz
+2f6f897c2c77c790f51b26850661b3dc  bundler-1.12.5.gem