$ sudo apt-get remove doctest 

Uninstall doctest including dependent package

If you would like to remove doctest and it's dependent packages which are no longer needed from Ubuntu,

$ sudo apt-get remove --auto-remove doctest 

Use Purging doctest

If you use with purge options to doctest package all the configuration and dependent packages will be removed.

$ sudo apt-get purge doctest 

If you use purge options along with auto remove, will be removed everything regarding the package, It's really useful when you want to reinstall again.

$ sudo apt-get purge --auto-remove doctest 

See Also,