I made a mistake in visudo, so it asked me what to do. I chose "e" and then MADE NO CHANGES. Upon exiting the editor, it went back to the shell, effectively locking me out, instead of telling me it was still borken:

[revragnarok@machine jenkins]$ sudo visudo 
[sudo] password for revragnarok: 
Your password will expire in 3 day(s).
visudo: >>> /etc/sudoers: syntax error near line 113 <<<
What now? ?
Options are:
  (e)dit sudoers file again
  e(x)it without saving changes to sudoers file
  (Q)uit and save changes to sudoers file (DANGER!)

What now? e
[revragnarok@machine jenkins]$ sudo visudo 
sudo: >>> /etc/sudoers: syntax error near line 113 <<<
sudo: parse error in /etc/sudoers near line 113
revragnarok is not allowed to run sudo on machine.  This incident will be reported.

== Version info ==
[revragnarok@machine jenkins]$ rpm -q --whatprovides $(which visudo)
sudo-1.8.6p7-13.el7.x86_64
[revragnarok@machine jenkins]$ cat /etc/redhat-release 
CentOS Linux release 7.1.1503 (Core)