unravel

Gemfile

@@ -2,7 +2,7 @@ source :rubygems
 
 gemspec
 
-gem 'alchemist', :path => '~/alchemist'
+gem 'alchemist', :git => 'https://github.com/dkastner/alchemist.git', :branch => 'helpers'
 gem 'conversions'
 
 if RUBY_VERSION >= '1.9'

lib/data_miner.rb

@@ -47,9 +47,19 @@ def compress_whitespace(str)
       str.gsub(INNER_SPACE, ' ').strip
     end
 
+    # Set the unit converter.
+    #
+    # @note As of 2012-05-30, there are problems with the alchemist gem and the use of the conversions gem instead is recommended.
+    #
+    # @param [Symbol,nil] conversion_library Either +:alchemist+ or +:conversions+
+    #
+    # @return [nil]
     def unit_converter=(conversion_library)
-      @unit_converter = conversion_library ? DataMiner::UnitConverter.load(conversion_library) : nil
+      @unit_converter = UnitConverter.load conversion_library
+      nil
     end
+
+    # @return [#convert,nil] The user-selected unit converter or nil.
     def unit_converter
       @unit_converter
     end

lib/data_miner/attribute.rb

@@ -5,12 +5,6 @@ class DataMiner
   # @see DataMiner::Step::Import#store Telling an import step to store a column with DataMiner::Step::Import#store
   # @see DataMiner::Step::Import#key Telling an import step to key on a column with DataMiner::Step::Import#key
   class Attribute
-    class NoConverterSet < StandardError
-      def message
-        'You must set DataMiner.unit_converter to one of [:alchemist, :conversions] if you wish to convert units'
-      end
-    end
-
     class << self
       # @private
       def check_options(options)
@@ -21,7 +15,11 @@ def check_options(options)
         if (invalid_option_keys = options.keys - VALID_OPTIONS).any?
           errors << %{Invalid options: #{invalid_option_keys.map(&:inspect).to_sentence}}
         end
-        if (units_options = options.select { |k, _| k.to_s.include?('units') }).any? and VALID_UNIT_DEFINITION_SETS.none? { |d| d.all? { |required_option| options[required_option].present? } }
+        units_options = options.select { |k, _| k.to_s.include?('units') }
+        if units_options.any? and DataMiner.unit_converter.nil?
+          errors << %{You must set DataMiner.unit_converter to :alchemist or :conversions if you wish to convert units}
+        end
+        if units_options.any? and VALID_UNIT_DEFINITION_SETS.none? { |d| d.all? { |required_option| options[required_option].present? } }
           errors << %{#{units_options.inspect} is not a valid set of units definitions. Please supply a set like #{VALID_UNIT_DEFINITION_SETS.map(&:inspect).to_sentence}".}
         end
         errors
@@ -51,12 +49,12 @@ def check_options(options)
     ]
 
     VALID_UNIT_DEFINITION_SETS = [
-      [:units],
-      [:from_units, :to_units],
-      [:units_field_name],
-      [:units_field_name, :to_units],
-      [:units_field_number],
-      [:units_field_number, :to_units],
+      [:units],                         # no conversion
+      [:from_units, :to_units],         # yes
+      [:units_field_name],              # no
+      [:units_field_name, :to_units],   # yes
+      [:units_field_number],            # no
+      [:units_field_number, :to_units], # yes
     ]
 
     DEFAULT_SPLIT_PATTERN = /\s+/
@@ -191,6 +189,8 @@ def initialize(step, name, options = {})
       @overwrite = options.fetch :overwrite, DEFAULT_OVERWRITE
       @units_field_name = options[:units_field_name]
       @units_field_number = options[:units_field_number]
+      @convert_boolean = (@from_units.present? or (@to_units.present? and (@units_field_name.present? or @units_field_number.present?)))
+      @persist_units_boolean = (@to_units.present? or @units_field_name.present? or @units_field_number.present?)
       @dictionary_mutex = ::Mutex.new
     end
 
@@ -216,7 +216,7 @@ def set_from_row(local_record, remote_row)
         currently_nil = new_value.nil?
       end
 
-      if not currently_nil and units? and (final_to_units = (to_units || read_units(remote_row)))
+      if not currently_nil and persist_units? and (final_to_units = (to_units || read_units(remote_row)))
         local_record.send "#{name}_units=", final_to_units
       end
     end
@@ -257,14 +257,16 @@ def read(row)
         keep = split.fetch :keep, DEFAULT_SPLIT_KEEP
         value = value.to_s.split(pattern)[keep].to_s
       end
-      if value.blank? and (not stringlike_column? or nullify_blank_strings)
+      if value.blank? and (not text_column? or nullify_blank_strings)
         return
       end
       value = DataMiner.compress_whitespace value
       if upcase
         value = DataMiner.upcase value
       end
-      value = convert_units value, row
+      if convert?
+        value = convert_units value, row
+      end
       if sprintf
         if sprintf.end_with?('f')
           value = value.to_f
@@ -281,14 +283,12 @@ def read(row)
 
     # @private
     def convert_units(value, row)
-      enforce_conversion_options
-      if convert?
-        final_from_units = from_units || read_units(row)
-        final_to_units = to_units || read_units(row)
-        DataMiner.unit_converter.convert(value, final_from_units, final_to_units)
-      else
-        value
+      final_from_units = from_units || read_units(row)
+      final_to_units = to_units || read_units(row)
+      unless final_from_units and final_to_units
+        raise RuntimeError, "[data_miner] Missing units: from=#{final_from_units.inspect}, to=#{final_to_units.inspect}"
       end
+      DataMiner.unit_converter.convert value, final_from_units, final_to_units
     end
 
     # @private
@@ -302,10 +302,10 @@ def model
       step.model
     end
 
-    def stringlike_column?
-      return @stringlike_column_query[0] if @stringlike_column_query.is_a?(::Array)
-      @stringlike_column_query = [model.columns_hash[name.to_s].type == :string]
-      @stringlike_column_query[0]
+    def text_column?
+      return @text_column_query[0] if @text_column_query.is_a?(Array)
+      @text_column_query = [model.columns_hash[name.to_s].text?]
+      @text_column_query[0]
     end
 
     def static?
@@ -316,20 +316,12 @@ def dictionary?
       @dictionary_boolean
     end
 
-    def enforce_conversion_options
-      raise NoConverterSet if DataMiner.unit_converter.nil? and convert_options_present?
-    end
-
     def convert?
-      !DataMiner.unit_converter.nil? and convert_options_present?
-    end
-
-    def convert_options_present?
-      from_units.present? or units_field_name.present? or units_field_number.present?
+      @convert_boolean
     end
 
-    def units?
-      to_units.present? or units_field_name.present? or units_field_number.present?
+    def persist_units?
+      @persist_units_boolean
     end
 
     def read_units(row)

lib/data_miner/unit_converter.rb

@@ -1,13 +1,11 @@
 class DataMiner
   class UnitConverter
-    def self.load(type)
-      require "data_miner/unit_converter/#{type}"
-      const_get(type.to_s.camelize).new
-    end
-
-    def convert(value, from, to)
-      if from.blank? or to.blank?
-        raise ::RuntimeError, "[data_miner] Missing units (from=#{final_from_units.inspect}, to=#{final_to_units.inspect}"
+    class << self
+      def load(type)
+        if type
+          require "data_miner/unit_converter/#{type}"
+          const_get(type.to_s.camelcase).new
+        end
       end
     end
   end

lib/data_miner/unit_converter/alchemist.rb

@@ -4,7 +4,6 @@ class DataMiner
   class UnitConverter
     class Alchemist < UnitConverter
       def convert(value, from, to)
-        super
         value.to_f.send(from).to.send(to)
       end
     end

lib/data_miner/unit_converter/conversions.rb

@@ -4,8 +4,7 @@ class DataMiner
   class UnitConverter
     class Conversions < UnitConverter
       def convert(value, from, to)
-        super
-        value.to_f.send(from).to(to)
+        value.to_f.convert from, to
       end
     end
   end

test/data_miner/test_attribute.rb

@@ -1,54 +1,36 @@
-require_relative '../helper'
+require 'helper'
 
 describe DataMiner::Attribute do
   before do
     DataMiner.unit_converter = :alchemist
   end
 
-  describe '#enforce_conversion_options' do
-    it 'raises an error if no converter is set but options warrant conversion' do
-      DataMiner.unit_converter = nil
-      attribute = DataMiner::Attribute.new :foo, 'bar', :from_units => :pounds, :to_units => :kilograms
-      assert_raise DataMiner::Attribute::NoConverterSet do
-        attribute.send(:enforce_conversion_options)
-      end
-    end
-    it 'does not raise an error if a converter is set and options warrant conversion' do
-      attribute = DataMiner::Attribute.new :foo, 'bar', :from_units => :pounds, :to_units => :kilograms
-      assert_nothing_raised do
-        attribute.send(:enforce_conversion_options)
-      end
-    end
-    it 'does not raise an error if a converter is not set and no conversion options' do
-      DataMiner.unit_converter = nil
-      attribute = DataMiner::Attribute.new :foo, 'bar'
-      assert_nothing_raised do
-        attribute.send(:enforce_conversion_options)
-      end
-    end
-  end
-
   describe '#convert?' do
-    it 'returns true if a converter and from_units are set' do
+    it 'returns true if from_units is set' do
       attribute = DataMiner::Attribute.new :foo, 'bar', :from_units => :pounds, :to_units => :kilograms
       assert attribute.send(:convert?)
     end
-    it 'returns true if a converter and units_field_name are set' do
-      attribute = DataMiner::Attribute.new :foo, 'bar', :units_field_name => 'bar'
+    it 'returns true if to_units and units_field_name are set' do
+      attribute = DataMiner::Attribute.new :foo, 'bar', :units_field_name => 'bar', :to_units => :kilograms
       assert attribute.send(:convert?)
     end
-    it 'returns true if a converter and units_field_number are set' do
-      attribute = DataMiner::Attribute.new :foo, 'bar', :units_field_number => 3
+    it 'returns true if to_units and units_field_number are set' do
+      attribute = DataMiner::Attribute.new :foo, 'bar', :units_field_number => 3, :to_units => :kilograms
       assert attribute.send(:convert?)
     end
-    it 'returns false if there is no converter' do
-      DataMiner.unit_converter = nil
-      attribute = DataMiner::Attribute.new :foo, 'bar', :from_units => :pounds, :to_units => :kilograms
-      assert !attribute.send(:convert?)
+    it 'returns false if units_field_name only is set' do
+      attribute = DataMiner::Attribute.new :foo, 'bar', :units_field_name => 'bar'
+      refute attribute.send(:convert?)
+    end
+    it 'returns false if units_field_number only is set' do
+      attribute = DataMiner::Attribute.new :foo, 'bar', :units_field_number => 'bar'
+      refute attribute.send(:convert?)
     end
-    it 'returns false if there is a converter but no units' do
-      attribute = DataMiner::Attribute.new :foo, 'bar'
-      assert !attribute.send(:convert?)
+    it 'raises if no converter and units are used' do
+      DataMiner.unit_converter = nil
+      lambda {
+        DataMiner::Attribute.new :foo, 'bar', :from_units => :pounds, :to_units => :kilograms
+      }.must_raise ArgumentError, /unit_converter/
     end
   end
 end

test/data_miner/unit_converter/test_alchemist.rb

@@ -1,4 +1,4 @@
-require_relative '../../helper'
+require 'helper'
 
 describe 'DataMiner::UnitConverter::Alchemist' do
   before do

test/data_miner/unit_converter/test_conversions.rb

@@ -1,4 +1,4 @@
-require_relative '../../helper'
+require 'helper'
 
 describe 'DataMiner::UnitConverter::Conversions' do
   before do

test/helper.rb

@@ -8,10 +8,8 @@
 require 'minitest/spec'
 require 'minitest/autorun'
 require 'minitest/reporters'
-require 'test/unit/assertions'
 MiniTest::Unit.runner = MiniTest::SuiteRunner.new
 MiniTest::Unit.runner.reporters << MiniTest::Reporters::SpecReporter.new
-include Test::Unit::Assertions
 
 require 'active_record'
 require 'logger'
@@ -29,7 +27,7 @@
 
 require 'data_miner'
 
-def init_database(unit_converter = :alchemist)
+def init_database(unit_converter = :conversions)
   cmd = %{mysql -u root -ppassword -e "DROP DATABASE data_miner_test; CREATE DATABASE data_miner_test CHARSET utf8"}
   $stderr.puts "Running `#{cmd}`..."
   system cmd
@@ -40,14 +38,14 @@ def init_database(unit_converter = :alchemist)
   DataMiner::Run.clear_locks
 
   DataMiner.unit_converter = unit_converter
+end
+
+def init_models
+  require 'support/breed'
+  require 'support/pet'
+  Pet.auto_upgrade!
 
   ActiveRecord::Base.descendants.each do |model|
     model.attr_accessible nil
   end
 end
-
-def init_pet
-  require_relative './support/breed'
-  require_relative './support/pet'
-  Pet.auto_upgrade!
-end

test/support/data_miner_with_alchemist.rb

@@ -1,9 +1,9 @@
-require_relative '../helper'
+require 'helper'
 
 describe 'DataMiner with Alchemist' do
   before do
     init_database(:alchemist)
-    init_pet
+    init_models
     Pet.run_data_miner!
   end
 

test/support/data_miner_with_conversions.rb

@@ -1,12 +1,12 @@
-require_relative '../helper'
+require 'helper'
 
 require 'conversions'
 Conversions.register :years, :years, 1
 
 describe 'DataMiner with Conversions' do
   before do
     init_database(:conversions)
-    init_pet
+    init_models
     Pet.run_data_miner!
   end
 

test/support/data_miner_without_unit_converter.rb

@@ -1,4 +1,4 @@
-require_relative '../helper'
+require 'helper'
 
 class MyPet < ActiveRecord::Base
   PETS = File.expand_path('../pets.csv', __FILE__)
@@ -30,7 +30,6 @@ class MyPet < ActiveRecord::Base
   end
 end
 
-
 describe 'DataMiner with Conversions' do
   it 'happens when DataMiner.unit_converter is nil' do
     DataMiner.unit_converter.must_be_nil
@@ -45,7 +44,7 @@ class MyPet < ActiveRecord::Base
   it 'raises an error if conversions are attempted' do
     init_database(nil)
     lambda do
-      init_pet
+      init_models
       Pet.run_data_miner!
     end.must_raise DataMiner::Attribute::NoConverterSet
   end