diff --git a/Gemfile b/Gemfile
index d7fea8b..9f78bc7 100644
--- a/Gemfile
+++ b/Gemfile
@@ -6,10 +6,10 @@ gem "thor", ">= 0.14.0"
 # Add dependencies to develop your gem here.
 # Include everything needed to run rake, tests, features, etc.
 group :development do
-  gem "rake"
-  gem "rspec", "~> 2.1.0"
+  gem "rake", "~> 0.8.7"
+  gem "rspec", "~> 2.10"
   gem "jeweler", ">= 1.6.2"
-  gem "rcov", ">= 0"
+  gem "rcov", :platforms => :mri_18
+  gem "simplecov", :platforms => :mri_19
   gem "test-construct"
-  gem "ruby-debug"
 end
diff --git a/Gemfile.lock b/Gemfile.lock
index 2bee71a..1844d0e 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,40 +1,42 @@
 GEM
   remote: http://rubygems.org/
   specs:
-    columnize (0.3.2)
-    diff-lcs (1.1.2)
+    diff-lcs (1.1.3)
     git (1.2.5)
-    jeweler (1.6.2)
+    jeweler (1.8.3)
       bundler (~> 1.0)
       git (>= 1.2.5)
       rake
-    linecache (0.43)
-    rake (0.9.2)
-    rcov (0.9.9)
-    rspec (2.1.0)
-      rspec-core (~> 2.1.0)
-      rspec-expectations (~> 2.1.0)
-      rspec-mocks (~> 2.1.0)
-    rspec-core (2.1.0)
-    rspec-expectations (2.1.0)
-      diff-lcs (~> 1.1.2)
-    rspec-mocks (2.1.0)
-    ruby-debug (0.10.4)
-      columnize (>= 0.1)
-      ruby-debug-base (~> 0.10.4.0)
-    ruby-debug-base (0.10.4)
-      linecache (>= 0.3)
+      rdoc
+    json (1.7.3)
+    multi_json (1.3.6)
+    rake (0.8.7)
+    rcov (1.0.0)
+    rdoc (3.12)
+      json (~> 1.4)
+    rspec (2.10.0)
+      rspec-core (~> 2.10.0)
+      rspec-expectations (~> 2.10.0)
+      rspec-mocks (~> 2.10.0)
+    rspec-core (2.10.1)
+    rspec-expectations (2.10.0)
+      diff-lcs (~> 1.1.3)
+    rspec-mocks (2.10.1)
+    simplecov (0.6.4)
+      multi_json (~> 1.0)
+      simplecov-html (~> 0.5.3)
+    simplecov-html (0.5.3)
     test-construct (1.2.0)
-    thor (0.14.6)
+    thor (0.15.2)
 
 PLATFORMS
   ruby
 
 DEPENDENCIES
   jeweler (>= 1.6.2)
-  rake
+  rake (~> 0.8.7)
   rcov
-  rspec (~> 2.1.0)
-  ruby-debug
+  rspec (~> 2.10)
+  simplecov
   test-construct
   thor (>= 0.14.0)