check_directory_exist.yml

---
    # Attempt to check if the folder exist. 
    # If it exist echo out a string. You have to echo something
    # if the directory does exist or else the task is considered failed
    # Output is set to $is_default_created. Note that this variable is
    # object and not an atomic value. 
    - name: Attempt to check if a directory exist
      action: shell test -d /my/folder && echo "exist" || echo ""
      register: is_folder_created

    # Do an operation of somekind if the folder does not exist
    - name: Do an operation if folder does not exist
      action: command echo "Operation Yashima"
      when_string: ${is_folder_created.stdout} != "exist"

You can now uses the stat module to check if a file exists and is a directory.
See http://docs.ansible.com/stat_module.html