diff --git a/omniauth-rails_csrf_protection.gemspec b/omniauth-rails_csrf_protection.gemspec
index 2eed452..da237b3 100644
--- a/omniauth-rails_csrf_protection.gemspec
+++ b/omniauth-rails_csrf_protection.gemspec
@@ -22,8 +22,8 @@ Gem::Specification.new do |spec|
   spec.homepage    = "https://github.com/cookpad/omniauth-rails_csrf_protection"
   spec.license     = "MIT"
 
-  spec.files       = `git ls-files`
-  spec.test_files  = `git ls-files -- {test}/*`.split("\n")
+  spec.files       = `git ls-files`.split("\n")
+  spec.test_files  = `git ls-files -- test/*`.split("\n")
 
   spec.require_paths = ["lib"]