diff --git a/Rakefile b/Rakefile
index 2b5ca481..4a3884e1 100644
--- a/Rakefile
+++ b/Rakefile
@@ -3,6 +3,8 @@ begin
 require "rake/extensiontask"
 require "rake_compiler_dock"
 require "shellwords"
+require "rspec/core/rake_task"
+
 
 spec = Bundler::GemHelper.gemspec
 
@@ -12,6 +14,9 @@ Rake::ExtensionTask.new("numo/narray", spec) do |ext|
   ext.cross_platform = cross_platforms
 end
 
+RSpec::Core::RakeTask.new("spec")
+Rake::Task[:spec].prerequisites << :compile
+
 pkg_dir = "pkg"
 windows_gem_paths = cross_platforms.collect do |platform|
   File.join(pkg_dir, "#{spec.full_name}-#{platform}.gem")
diff --git a/spec/bit_spec.rb b/spec/bit_spec.rb
index bc368635..e69ffdc7 100644
--- a/spec/bit_spec.rb
+++ b/spec/bit_spec.rb
@@ -1,4 +1,4 @@
-require File.join(File.dirname(__FILE__), "../ext/numo/narray/narray")
+require_relative '../lib/numo/narray.so'
 #Numo::NArray.debug = true
 
 RSpec.configure do |config|
diff --git a/spec/narray_spec.rb b/spec/narray_spec.rb
index 93e70480..f569baaa 100644
--- a/spec/narray_spec.rb
+++ b/spec/narray_spec.rb
@@ -1,4 +1,4 @@
-require File.join(File.dirname(__FILE__), "../ext/numo/narray/narray")
+require_relative "../lib/numo/narray.so"
 #Numo::NArray.debug = true
 
 RSpec.configure do |config|