diff --git a/lib/dm-core.rb b/lib/dm-core.rb
index 88d78b27..d2d6c7e4 100644
--- a/lib/dm-core.rb
+++ b/lib/dm-core.rb
@@ -168,28 +168,10 @@ def self.root
   #
   # @api public
   def self.setup(*args)
-    if args.first.kind_of?(DataMapper::Adapters::AbstractAdapter)
-      adapter = args.first
+    adapter = if args.first.kind_of?(Adapters::AbstractAdapter)
+      args.first
     else
-      name, uri_or_options = args
-
-      options = normalize_options(uri_or_options)
-
-      adapter_name = options[:adapter]
-      class_name   = (Extlib::Inflection.camelize(adapter_name) + 'Adapter').to_sym
-
-      unless Adapters.const_defined?(class_name)
-        lib_name = "#{adapter_name}_adapter"
-        file     = root / 'lib' / 'dm-core' / 'adapters' / "#{lib_name}.rb"
-
-        if file.file?
-          require file
-        else
-          require lib_name
-        end
-      end
-
-      adapter = Adapters.const_get(class_name).new(name, options)
+      DataMapper::Adapters.new(*args)
     end
 
     Repository.adapters[adapter.name] = adapter
@@ -223,30 +205,4 @@ def self.repository(name = nil)
       current_repository
     end
   end
-
-  # Turns options hash or connection URI into
-  # options hash used by the adapter
-  #
-  # @api private
-  def self.normalize_options(uri_or_options)
-    assert_kind_of 'uri_or_options', uri_or_options, Addressable::URI, Hash, String
-
-    if uri_or_options.kind_of?(Hash)
-      uri_or_options.to_mash
-    else
-      uri     = uri_or_options.kind_of?(String) ? Addressable::URI.parse(uri_or_options) : uri_or_options
-      options = uri.to_hash.to_mash
-
-      # Extract the name/value pairs from the query portion of the
-      # connection uri, and set them as options directly.
-      if options[:query]
-        options.update(uri.query_values)
-      end
-
-      options[:adapter] = options[:scheme]
-
-      options
-    end
-  end
-
 end
diff --git a/lib/dm-core/adapters.rb b/lib/dm-core/adapters.rb
index e2ab1ce4..4e72abe8 100644
--- a/lib/dm-core/adapters.rb
+++ b/lib/dm-core/adapters.rb
@@ -1,6 +1,140 @@
 module DataMapper
   module Adapters
     extend Chainable
+    extend Extlib::Assertions
+
+    ##
+    # Set up an adapter for a storage engine
+    #
+    # @see DataMapper.setup
+    #
+    # @api private
+    def self.new(repository_name, options)
+      options = normalize_options(options)
+      adapter_class(options[:adapter]).new(repository_name, options)
+    end
+
+    class << self
+      private
+
+      ##
+      # Normalize the arguments passed to new()
+      #
+      # Turns options hash or connection URI into the options hash used
+      # by the adapter.
+      #
+      # @param [Hash, Addressable::URI, String] options
+      #   the options to be normalized
+      #
+      # @return [Mash]
+      #   the options normalized as a Mash
+      #
+      # @api private
+      def normalize_options(options)
+        case options
+          when Hash             then normalize_options_hash(options)
+          when Addressable::URI then normalize_options_uri(options)
+          when String           then normalize_options_string(options)
+          else
+            raise ArgumentError, "+options+ should be a Hash, String or Addressable::URI, but was #{uri_or_options.class.name}", caller(2)
+        end
+      end
+
+      ##
+      # Normalize Hash options into a Mash
+      #
+      # @param [Hash] hash
+      #   the hash to be normalized
+      #
+      # @return [Mash]
+      #   the options normalized as a Mash
+      #
+      # @api private
+      def normalize_options_hash(hash)
+        options = hash.to_mash
+
+        if options.key?(:scheme)
+          options[:adapter] ||= options[:scheme]
+        end
+
+        options
+      end
+
+      ##
+      # Normalize Addressable::URI options into a Mash
+      #
+      # @param [Addressable::URI] uri
+      #   the uri to be normalized
+      #
+      # @return [Mash]
+      #   the options normalized as a Mash
+      #
+      # @api private
+      def normalize_options_uri(uri)
+        options = normalize_options_hash(uri.to_hash)
+
+        # Extract the name/value pairs from the query portion of the
+        # connection uri, and set them as options directly.
+        if options[:query]
+          options.update(uri.query_values)
+        end
+
+        options
+      end
+
+      ##
+      # Normalize String options into a Mash
+      #
+      # @param [String] string
+      #   the string to be normalized
+      #
+      # @return [Mash]
+      #   the options normalized as a Mash
+      #
+      # @api private
+      def normalize_options_string(string)
+        normalize_options_uri(Addressable::URI.parse(string))
+      end
+
+      ##
+      # Return the adapter class constant
+      #
+      # @param [Symbol] name
+      #   the name of the adapter
+      #
+      # @return [Class]
+      #   the AbstractAdapter subclass
+      #
+      # @api private
+      def adapter_class(name)
+        class_name = (Extlib::Inflection.camelize(name) + 'Adapter').to_sym
+        load_adapter(name) unless const_defined?(class_name)
+        const_get(class_name)
+      end
+
+      ##
+      # Require the adapter library
+      #
+      # @param [Symbol] name
+      #   the name of the adapter
+      #
+      # @return [TrueClass, FalseClass]
+      #   true if the adapter is loaded
+      #
+      # @api private
+      def load_adapter(name)
+        assert_kind_of 'name', name, String, Symbol
+
+        lib  = "#{name}_adapter"
+        file = DataMapper.root / 'lib' / 'dm-core' / 'adapters' / "#{lib}.rb"
+
+        if file.file?
+          require file
+        else
+          require lib
+        end
+      end
+    end
 
     extendable do
       # TODO: document