diff --git a/.gitignore b/.gitignore
index e72a40f..7642f94 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,4 @@
 plek-*.gem
 Gemfile.lock
+# simplecov
+coverage/
diff --git a/plek.gemspec b/plek.gemspec
index 1b94a94..746568a 100644
--- a/plek.gemspec
+++ b/plek.gemspec
@@ -20,4 +20,5 @@ Gem::Specification.new do |s|
   s.add_development_dependency "minitest"
   s.add_development_dependency "rake"
   s.add_development_dependency "rubocop-govuk", "4.16.1"
+  s.add_development_dependency "simplecov"
 end
diff --git a/test/test_helper.rb b/test/test_helper.rb
index 2a82d5c..402cd6d 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -1,3 +1,6 @@
+require "simplecov"
+SimpleCov.start
+
 require "minitest/autorun"
 require "climate_control"