diff --git a/.ruby-version b/.ruby-version
new file mode 100644
index 0000000..2f4b607
--- /dev/null
+++ b/.ruby-version
@@ -0,0 +1 @@
+3.4
diff --git a/Gemfile b/Gemfile
index ea1ffee..29fb48b 100644
--- a/Gemfile
+++ b/Gemfile
@@ -2,4 +2,5 @@ source "https://rubygems.org/"
 group :development, :test do
   gem 'rake', '~> 0.9.2'
   gem "rdoc", '~> 3.12'
+  gem "test-unit"
 end
diff --git a/Gemfile.lock b/Gemfile.lock
index 8b1fd4a..eedb4ab 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,10 +1,13 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    json (1.6.5)
+    json (1.8.6)
+    power_assert (3.0.1)
     rake (0.9.2.2)
     rdoc (3.12)
       json (~> 1.4)
+    test-unit (3.7.7)
+      power_assert
 
 PLATFORMS
   ruby
@@ -12,3 +15,7 @@ PLATFORMS
 DEPENDENCIES
   rake (~> 0.9.2)
   rdoc (~> 3.12)
+  test-unit
+
+BUNDLED WITH
+  4.0.3
diff --git a/lib/pdf/toolkit.rb b/lib/pdf/toolkit.rb
index 4ac2c5c..b990bbc 100644
--- a/lib/pdf/toolkit.rb
+++ b/lib/pdf/toolkit.rb
@@ -387,7 +387,7 @@ def write_info_to_file(out)
     end
     retval
   ensure
-    File.unlink(tmp) if tmp && File.exists?(tmp)
+    File.unlink(tmp) if tmp && File.exist?(tmp)
   end
 
   def update
diff --git a/pdf-toolkit.gemspec b/pdf-toolkit.gemspec
index b198fac..0a8bccd 100644
--- a/pdf-toolkit.gemspec
+++ b/pdf-toolkit.gemspec
@@ -16,7 +16,6 @@ Gem::Specification.new do |s|
   s.rubyforge_project = 'pdf-toolkit'
   s.homepage = "http://pdf-toolkit.rubyforge.org"
 
-  s.has_rdoc = true
   s.require_path = 'lib'
 
   s.files = [ "Rakefile", "README.md", "pdf-toolkit.gemspec" ]