diff --git a/Rakefile b/Rakefile
index f0acaa0..652470a 100644
--- a/Rakefile
+++ b/Rakefile
@@ -3,13 +3,12 @@ require "rubocop/rake_task"
 RuboCop::RakeTask.new
 
 targeted_files = ARGV.drop(1)
-file_pattern = targeted_files.empty? ? "spec/**/*_spec.rb" : targeted_files
 
 require "rspec/core"
 require "rspec/core/rake_task"
 
 RSpec::Core::RakeTask.new(:spec) do |t|
-  t.pattern = FileList[file_pattern]
+  t.pattern = targeted_files unless targeted_files.empty?
 end
 
 RSpec.configure do |config|