In Rails 1.1.5, the basic generator generates the following code for the fixture used in database unit tests:

   1  
   2  # Read about fixtures at http://ar.rubyonrails.org/classes/Fixtures.html
   3  first:
   4    id: 1
   5  another:
   6    id: 2

As ActiveRecord provides database reflexion features, we can generate a fixture file with all the columns' name prepopulated for number and text types, such as:

   1  
   2  # Read about fixtures at http://ar.rubyonrails.org/classes/Fixtures.html
   3  first:
   4    id: 1
   5    short_title: short_title_first
   6    title: title_first

This will be done by the following class:

   1  
   2  require_gem 'activerecord'
   3  
   4  class RailsFixturesGenerator
   5  
   6    def generate(class_name)
   7      
   8      # Get the "Class" object from the class name        
   9      model_class = Object.const_get(class_name)
  10      
  11      yaml_content =  "# Read about fixtures at http://ar.rubyonrails.org/classes/Fixtures.html\n"
  12      yaml_content += "first:\n"
  13      
  14      # get if first!   
  15      model_class.columns.each { |column|
  16        
  17        yaml_content += "  " + column.name + ": "
  18        
  19        if column.number?
  20          yaml_content +=  "1"
  21        end
  22        if column.text?
  23          # @todo /!\ max length
  24          yaml_content +=  column.name + "_first"
  25        end
  26        
  27        yaml_content += "\n"      
  28      }  
  29      
  30      write_fixture_file(model_class, yaml_content)
  31      
  32      yaml_content            
  33    end  
  34    
  35    # Write the <fixture> yaml file  in the test/fixtures folder
  36    def write_fixture_file(model_class, yaml_content)
  37      
  38      path = ENV['DEST'] || "#{RAILS_ROOT}/test/fixtures"
  39      db   = ENV['DB']   || 'test'
  40      
  41      File.open("#{path}/#{model_class.table_name}.yml", 'wb') do |file|    
  42        file.write yaml_content 
  43        file.close    
  44      end
  45    end
  46  end

Of course, I have an unit test that I wrote before the code ;-)
This was my first "complex" method I wrote in Ruby so please bear with me. Any feedback is welcome. I want to write a Rails plugin in order to share the generators I will write.