How can I mock an instance variable in rspec
<p>I have two class <code>OneClass</code> and <code>AnotherClass</code>:</p>

<pre><code>class OneClass
  def initialize(*args)
    @another_member = AnotherClass.new()
  end

  def my_method()
    if @another_member.another_method1() then
      @another_member.another_method2()
    end
    @another_member.another_method3()
  end
end
</code></pre>

<p>I am getting to write unit for <code>OneClass</code>. 
How can I mock <code>@another_member</code>?</p>