dm_new_style_adapter_requiring.rb

require 'active_support/inflector'

# dm-core/spec/adapter.rb
module DataMapper
  module Spec
    module Adapters

      def self.setup(adapter_name)
        SpecAdapter.new(adapter_name)
      end

      def self.adapter
        SpecAdapter.adapter
      end

      class SpecAdapter

        attr_accessor :adapter
        attr_reader   :name

        class << self

          def new(name)
            klass = lookup(name)
            equal?(klass) ? super(name) : klass.new(name)
          end

          attr_reader :adapter

        private


          def lookup(adapter)
            klass_name = adapter.camelize
            unless DataMapper::Spec::Adapters.const_defined?("#{klass_name}Adapter")
              raise "Adapter #{adapter} not supported (#{klass_name}Adapter)"
            end
            const_get(klass_name)
          end

          def adapter=(adapter)
            @adapter = adapter
          end

        end


        def setup
          begin
            adapter = DataMapper.setup(name, connection_string)
            test_connection
            self.class.adapter = adapter
           rescue Exception => e
             puts "Could not connect to the database using '#{connection_string}' because of: #{e.inspect}"
          end
        end


        def name
          @name ||= (ENV['ADAPTER'] || 'in_memory')
        end

        def adapter_name
          "dm-#{name}-adapter"
        end


        def connection_string
          "#{name}://#{credentials}@localhost/datamapper_tests"
        end
        
        def credentials
          "#{username}:#{password}"
        end
        
        def username
          'datamapper'
        end
        
        def password
          'datamapper'
        end


        def test_connection
          if adapter.respond_to?(:select)
            connection_test
          end
        end

        # Test the connection
        #
        # Overwrite this method if you need to perform custom connection testing
        #
        # @raise [Exception]
        def connection_test
          adapter.select('SELECT 1')
        end

        def temp_db_dir
          Dir.tmpdir
        end

      private

        def initialize(name)
          @name, @adapter = name.to_sym, nil
        end

      end

    end
  end
end

# ------------------------------------------------------------------------------------------------

# dm-core/spec/spec_helper.rb
require "dm-#{ENV['ADAPTER']}-adapter/spec/setup"

# ------------------------------------------------------------------------------------------------

# dm-sqlite-adapter/lib/dm-sqlite-adapter/spec/setup.rb
module DataMapper
  module Spec
    module Adapters

      class SqliteAdapter < SpecAdapter 
        def connection_string
          "sqlite3://#{temp_db_dir}/datamapper_tests.db"
        end
      end

      setup ENV['ADAPTER'] || :sqlite

    end
  end
end

# ------------------------------------------------------------------------------------------------

# dm-mysql-adapter/lib/dm-mysql-adapter/spec/setup.rb
module DataMapper
  module Spec
    module Adapters

      class MysqlAdapter < SpecAdapter
      end

      setup ENV['ADAPTER'] || :mysql

    end
  end
end

# ------------------------------------------------------------------------------------------------

# dm-postgres-adapter/lib/dm-postgres-adapter/spec/setup.rb
module DataMapper
  module Spec
    module Adapters

      class PostgresAdapter < SpecAdapter
      end

      setup ENV['ADAPTER'] || :postgres

    end
  end
end


# ------------------------------------------------------------------------------------------------

# dm-oracle-adapter/lib/dm-oracle-adapter/spec/setup.rb
module DataMapper
  module Spec
    module Adapters

      class OracleAdapter < SpecAdapter 
        def connection_test
          adapter.select('SELECT 1 FROM dual')
        end
      end

      setup ENV['ADAPTER'] || :oracle

    end
  end
end

# ------------------------------------------------------------------------------------------------

# dm-sqlserver-adapter/lib/dm-sqlserver-adapter/spec/setup.rb
module DataMapper
  module Spec
    module Adapters

      class SqlserverAdapter < SpecAdapter 
        def connection_string
          "#{super};instance=SQLEXPRESS"
        end
      end

      setup ENV['ADAPTER'] || :sqlserver

    end
  end
end