Rakefile in ffprober-0.4.6 vs Rakefile in ffprober-0.5.1

@@ -1,9 +1,18 @@
 require "bundler/gem_tasks"
+require "rake/testtask"
+
+Rake::TestTask.new(:test) do |t|
+  t.libs << "test"
+  t.libs << "lib"
+  t.test_files = FileList['test/**/*_test.rb']
+end
+
+task default: :test