diff --git a/Gemfile b/Gemfile
index cc03f19..38cbe41 100644
--- a/Gemfile
+++ b/Gemfile
@@ -82,6 +82,7 @@ group :test do
   gem "test-unit", :platforms => platforms
   gem "mocha", "0.12.3"
   gem 'capybara', '~> 2.0.0'
+  gem 'simplecov', :platforms => [:mri_19]
 end
 
 local_gemfile = File.join(File.dirname(__FILE__), "Gemfile.local")
diff --git a/lib/tasks/redmine.rake b/lib/tasks/redmine.rake
index 0ad4f2f..619fbeb 100644
--- a/lib/tasks/redmine.rake
+++ b/lib/tasks/redmine.rake
@@ -119,6 +119,18 @@ namespace :redmine do
         t.pattern = "plugins/#{ENV['NAME'] || '*'}/test/integration/**/*_test.rb"
       end
     end
+
+    desc 'Measures test coverage for a plugin.'
+    task :coverage do
+      name = ENV['NAME']
+      abort 'this task requires an argument NAME' unless name
+      abort "plugin #{name} not found" unless File.directory?("plugins/#{name}")
+      cd "plugins/#{name}"
+      rm_f "coverage"
+      require 'simplecov'
+      SimpleCov.start 'rails'
+      Dir.glob('test/**/*_test.rb').each { |f| require "./#{f}" }
+    end
   end
 end