Refactor csv_importer and improve test accuracy

Previously the "GenericWork" argument was not useful for anything and
the test data did not trigger the initializer argument to be relevant.

The importer was not extensible w/ an arbitrary class because it relied
on exclusively on the `Factory.for` invocation.  Now, as the spec
demonstrates, a user can use an arbitrary or even anonymous class.

Much YARD added.

lib/importer/csv_importer.rb

@@ -3,12 +3,17 @@ module Importer
   # header row. The model for each row can either be specified in a column called
   # 'type' or globally by passing the model attribute
   class CSVImporter
+    # @param [String] metadata_file path to CSV file
+    # @param [String] files_directory path, passed to factory constructor
+    # @param [#to_s, Class] model if Class, the factory class to be invoked per row.
+    # Otherwise, the stringable first (Xxx) portion of an "XxxFactory" constant.
     def initialize(metadata_file, files_directory, model = nil)
-      @model = model
-      @files_directory = files_directory
       @metadata_file = metadata_file
+      @files_directory = files_directory
+      @model = model
     end
 
+    # @return [Integer] count of objects created
     def import_all
       count = 0
       parser.each do |attributes|
@@ -24,16 +29,23 @@ def parser
         CSVParser.new(@metadata_file)
       end
 
-      # Build a factory to create the objects in fedora.
-      def create_fedora_objects(attributes)
-        model = attributes.delete(:type) || @model.to_s
+      # @return [Class] the model class to be used
+      def factory_class(model)
+        return model if model.is_a?(Class)
         if model.empty?
           $stderr.puts 'ERROR: No model was specified'
-          # rubocop:disable Rails/Exit
-          exit(1)
-          # rubocop:enable Rails/Exit
+          exit(1) # rubocop:disable Rails/Exit
         end
-        Factory.for(model).new(attributes, @files_directory).run
+        return Factory.for(model.to_s) if model.respond_to?(:to_s)
+        raise "Unrecognized model type: #{model.class}"
+      end
+
+      # Build a factory to create the objects in fedora.
+      # @param [Hash<Symbol => String>] attributes
+      # @option attributes [String] :type overrides model for a single object
+      # @note remaining attributes are passed to factory constructor
+      def create_fedora_objects(attributes)
+        factory_class(attributes.delete(:type) || @model).new(attributes, @files_directory).run
       end
   end
 end

lib/importer/factory.rb

@@ -11,6 +11,7 @@ module Factory
       autoload :WithAssociatedCollection
     end
 
+    # @param [#to_s] First (Xxx) portion of an "XxxFactory" constant
     def self.for(model_name)
       const_get "#{model_name}Factory"
     end