I am having trouble making the mount command here idempotent. I think it should work the way I've written it, but it isn't.

mount-devpts.yaml

---
# I want to verify that /dev/pts is mounted, and if not, mount it.
# Manually, this is simply: mount devpts /dev/pts -t devpts
# I want the resulting playbook to be idempotent and support the --check flag

- hosts: test
  remote_user: testroot

  tasks:
  # The simple "command" way to do this.
  - name: mount devpts with command module (this is idempotent thanks to the creates bit but command does not support --check)
    command: "mount devpts /dev/pts -t devpts"
    args:
      creates: /dev/pts/ptmx
  # The better way to do this, with the "mount" module.
  - name: mount devpts with mount module (not idempotent, --check says changed every time)
    mount: 
      path: /dev/pts
      src: devpts # I think this could be the issue but unsure how to best do this
      fstype: devpts
      state: present

...