Easier method for running the specs on a different backend

spec/helpers/backend_helper.rb

@@ -0,0 +1,43 @@
+module OAuthBackendHelper
+  module InMemory
+    def self.setup; end
+    def self.reset; end
+  end
+
+  module DataMapper
+    def self.setup
+      require 'dm-core'
+      ::DataMapper.setup(:default, "sqlite3:///tmp/oauth_provider_test.sqlite3")
+    end
+
+    def self.reset
+      OAuthProvider.create(:data_mapper)
+      ::DataMapper.auto_migrate!
+    end
+  end
+
+  def self.setup
+    backend_module.setup
+  end
+
+  def self.reset
+    backend_module.reset
+  end
+
+  def self.provider
+    OAuthProvider.create(backend_name)
+  end
+
+  def self.backend_module
+    klass_name = backend_name.to_s.split('_').map {|e| e.capitalize}.join
+    unless const_defined?(klass_name)
+      $stderr.puts "There is no backend for #{backend_name.inspect}"
+      exit!
+    end
+    const_get(klass_name)
+  end
+
+  def self.backend_name
+    (ENV["BACKEND"] || "in_memory").to_sym
+  end
+end

spec/spec_helper.rb

@@ -4,30 +4,21 @@
 require 'pp'
 
 require File.dirname(__FILE__) + '/../lib/oauth_provider'
+require File.dirname(__FILE__) + '/helpers/backend_helper'
 
-if ENV["DATAMAPPER"]
-  require 'dm-core'
-  DataMapper.setup(:default, "sqlite3:///tmp/oauth_provider_test.sqlite3")
-end
+OAuthBackendHelper.setup
 
 module OAuthProviderHelper
   def create_provider
-    if ENV["DATAMAPPER"]
-      OAuthProvider.create(:data_mapper)
-    else
-      OAuthProvider.create(:in_memory)
-    end
+    OAuthBackendHelper.provider
   end
 end
 
 Spec::Runner.configure do |config|
   config.include(OAuthProviderHelper)
 
   config.before(:each) do
-    if ENV["DATAMAPPER"]
-      OAuthProvider.create(:data_mapper)
-      DataMapper.auto_migrate!
-    end
+    OAuthBackendHelper.reset
   end
 end