Cucumber step definitions with blank association columns work intelligently

features/factory_girl_steps.feature

@@ -60,6 +60,18 @@ Feature: Use step definitions generated by factories
       | a title | 123       |
     And there should be 1 user
 
+  Scenario: create post with and without a category association
+    Given the following users exist:
+      | ID  | Name |
+      | 123 | Joe  |
+    And the following posts exist:
+      | Title                      | Author    | Category          |
+      | a title                    | Name: Joe | Name: programming |
+      | a title without a category | Name: Joe |                   |
+    Then I should find the following for the last post:
+      | title                      | category_id |
+      | a title without a category |             |
+
   Scenario: create a user without attributes
     Given a user exists
     Then there should be 1 user

features/support/factories.rb

@@ -7,10 +7,15 @@ class CreateSchema < ActiveRecord::Migration
   def self.up
     create_table :posts, :force => true do |t|
       t.integer :author_id
+      t.integer :category_id
       t.string  :title
       t.string  :body
     end
 
+    create_table :categories, :force => true do |t|
+      t.string :name
+    end
+
     create_table :users, :force => true do |t|
       t.string  :name
       t.boolean :admin, :default => false, :null => false
@@ -23,8 +28,12 @@ CreateSchema.suppress_messages { CreateSchema.migrate(:up) }
 class User < ActiveRecord::Base
 end
 
+class Category < ActiveRecord::Base
+end
+
 class Post < ActiveRecord::Base
   belongs_to :author, :class_name => 'User'
+  belongs_to :category
 end
 
 class NonActiveRecord
@@ -37,8 +46,13 @@ Factory.define :admin_user, :parent => :user do |f|
   f.admin true
 end
 
+Factory.define :category do |f|
+  f.name "programming"
+end
+
 Factory.define :post do |f|
   f.association :author, :factory => :user
+  f.association :category
 end
 
 # This is here to ensure that factory step definitions don't raise for a non-AR factory

lib/factory_girl/step_definitions.rb

@@ -1,6 +1,7 @@
 module FactoryGirlStepHelpers
   def convert_association_string_to_instance(factory_name, assignment)
     attribute, value = assignment.split(':', 2)
+    return if value.blank?
     attributes = convert_human_hash_to_attribute_hash(attribute => value.strip)
     factory = Factory.factory_by_name(factory_name)
     model_class = factory.build_class