Enable running tests without dep_selector

This ensures we don't accidentally load dep_selector where we don't mean
to.

.gitignore

@@ -4,6 +4,7 @@
 .config
 .yardoc
 Gemfile.lock
+NoGecode.gemfile.lock
 InstalledFiles
 _yardoc
 coverage

Gemfile

@@ -6,7 +6,10 @@ group :gecode do
   gem "dep_selector", "~> 1.0"
 end
 
-group :development do
+# If this group is named "development", then `bundle install --without
+# development` automagically excludes development dependencies that are listed
+# in the gemspec, which will skip installing rspec and then we can't run tests.
+group :dev do
   gem 'fuubar'
   gem 'yard'
   gem 'redcarpet'
@@ -28,10 +31,3 @@ group :development do
   end
 end
 
-group :test do
-  gem 'thor', '>= 0.16.0'
-  gem 'rake', '>= 0.9.2.2'
-
-  gem 'spork'
-  gem 'rspec'
-end

NoGecode.gemfile

@@ -0,0 +1,4 @@
+source 'https://rubygems.org'
+
+gemspec
+

Thorfile

@@ -28,4 +28,9 @@ class Default < Thor
   def spec
     exec "rspec --color --format=documentation spec"
   end
+
+  desc "spec", "Run RSpec code examples"
+  def nogecode_spec
+    exec "rspec -t '~gecode' --color --format=documentation spec"
+  end
 end

spec/acceptance/solutions_spec.rb

@@ -1,6 +1,6 @@
 require 'spec_helper'
 
-describe "Solutions" do
+describe "Solutions", :gecode do
 
   before do
     Solve.engine = :gecode