diff --git a/test/test_helper.rb b/test/test_helper.rb
index a288e0d..aba8070 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -1,4 +1,6 @@
-$LOAD_PATH.unshift File.expand_path('../lib', __dir__)
+require 'simplecov'
+SimpleCov.start
+
 require 'uplot'
 
 require 'test/unit'
diff --git a/uplot.gemspec b/uplot.gemspec
index 848652f..e8724a3 100644
--- a/uplot.gemspec
+++ b/uplot.gemspec
@@ -24,5 +24,6 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency 'bundler'
   spec.add_development_dependency 'rake'
   spec.add_development_dependency 'rubocop'
+  spec.add_development_dependency 'simplecov'
   spec.add_development_dependency 'test-unit'
 end