init.rb

class SpatialAdapterNotCompatibleError < StandardError
end

if defined? RAILS_ENV
  case ActiveRecord::Base.configurations[RAILS_ENV]['adapter']
  when 'mysql'
    require 'mysql_spatial_adapter'
  when 'postgresql'
    require 'post_gis_adapter'
  else
    raise SpatialAdapterNotCompatibleError.new("Only MySQL and PostgreSQL are currently supported by the spatial adapter plugin.")
  end
else
  # when testing RAILS_ENV isn't set so you'll need to use this style of getting the adapter name
  # [TODO] come back and make sure RAILS_ENV exists when running the plugin tests
  case ActiveRecord::Base.connection.adapter_name
  when 'MySQL'
    require 'mysql_spatial_adapter'
  when 'PostgreSQL'
    require 'post_gis_adapter'
   else
    raise SpatialAdapterNotCompatibleError.new("Only MySQL and PostgreSQL are currently supported by the spatial adapter plugin.")
   end
end