How to test console input with PHPUnit (readline function)

I'm creating a library and I want to test a system that asks the user by input in the console. I use PHPUnit as a testing library but and I don't know how to execute readline function and then print a text to answer the input to test it.

I've tested to replace readline by fgets(STDIN) but without results. I thought to solve the problem with asynchronous callables but I need guide for good libraries to use.

Thank for your help.