diff --git a/Gemfile.lock b/Gemfile.lock
index b7ef491..2c62a31 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -7,7 +7,9 @@ GEM
   remote: https://rubygems.org/
   specs:
     diff-lcs (1.2.5)
+    docile (1.1.5)
     json (1.8.1)
+    multi_json (1.10.1)
     rake (10.3.2)
     rdoc (4.1.1)
       json (~> 1.4)
@@ -24,6 +26,11 @@ GEM
     rspec-mocks (3.0.2)
       rspec-support (~> 3.0.0)
     rspec-support (3.0.2)
+    simplecov (0.8.2)
+      docile (~> 1.1.0)
+      multi_json
+      simplecov-html (~> 0.8.0)
+    simplecov-html (0.8.0)
     yard (0.8.7.4)
 
 PLATFORMS
@@ -34,5 +41,6 @@ DEPENDENCIES
   rdoc
   redcarpet
   rspec
+  simplecov
   yard
   yawpa!
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index a539461..67730b6 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -1 +1,7 @@
-require 'yawpa'
+require "simplecov"
+
+SimpleCov.start do
+  add_filter "/spec/"
+end
+
+require "yawpa"
diff --git a/yawpa.gemspec b/yawpa.gemspec
index fbbe0f2..5c8543f 100644
--- a/yawpa.gemspec
+++ b/yawpa.gemspec
@@ -16,6 +16,7 @@ Gem::Specification.new do |gem|
   gem.version       = Yawpa::VERSION
 
   gem.add_development_dependency "rspec"
+  gem.add_development_dependency "simplecov"
   gem.add_development_dependency "rake"
   gem.add_development_dependency "rdoc"
   gem.add_development_dependency "yard"