How do I test a function with gets.chomp in it?

I have a simple function using gets.chomp like this:

def welcome_user
   puts "Welcome! What would you like to do?"
   action = gets.chomp
end 

I'd like to test it using ruby's built in TestCase suite like this:

class ViewTest < Test::Unit::TestCase
   def test_welcome
      welcome_user      
   end 
end 

The problem is, when I run that test, the gets.chomp stops the test because it needs the user to enter in something. Is there a way I can simulate user inputs using just ruby?