Rakefile in ruby-graphviz-1.0.1 vs Rakefile in ruby-graphviz-1.0.2

@@ -40,10 +40,16 @@
       'lib/graphviz/family_tree/person.rb',
       'lib/graphviz/family_tree/sibling.rb']
 end
 
 Rake::TestTask.new(:test) do |t|
-  t.test_files = FileList['test/test_*.rb']
+  require 'graphviz/utils'
+  include GVUtils
+  if find_executable("dot", nil).nil?
+    t.test_files = FileList['test/test_*.rb'].exclude("test/test_examples.rb") 
+  else
+    t.test_files = FileList['test/test_*.rb']
+  end
 end
 
 Bundler::GemHelper.install_tasks
 
 namespace :gemcutter do