Initialize Ruby module - ruby-on-rails

Question

Trying to learn Ruby and below is a module I have created in order to test IO Ruby features. When I run the following tests:
subject{TestGem.new}
it 'should be_a Module' do
subject.is_a Module
end
it 'creates a config file' do
subject.init_config
File.open("program.config", "r") { |io| io.readline }.should eq "default_file.txt"
end
I get this error for both:
Failure/Error: subject{TestGem.new}
NoMethodError:
undefined method `new' for TestGem:Module
Here is the Module I am testing. Any help/suggestions would greatly appreciated :)
$LOAD_PATH.unshift File.expand_path("../test_gem", __FILE__)
require 'version'
require 'hello'
module TestGem
#default_file_name
#supported_types
def initialize
default_file_name = 'default_file.txt'
supported_types = ['txt', 'pdf']
end
puts "module TestGem defined"
def self.init_config
File.open('program.config', "w") do |f|
f.write(yaml(#default_file_name))
f.write(yaml(#supported_types))
end
end
class MyFile
def self.first(filename)
File.open(filename, "r") {|f| f.readline}
end
def self.last(filename)
File.open(filename, "r")[-1]
end
end
class MyError < StandardError
puts "Standard Error"
end
end

Answer 1

Short answer: You can't instantiate modules objects
module A
end
class B
end
B.methods - A.methods #=> [:new, :superclass, :allocate]
To test a module you can include it in a object like this
object = Object.new
object.extend(TestGem)
Or you can create some example class if your module depends on some class behavior.