In accordance with http://miroslav.suchy.cz/blog/archives/2013/10/07/donate_1_minute_of_your_time_to_test_upgrades_from_f19_to_f20/index.html I was trying to see if an potential upgrade from Fedora 19 to 20 would go smoothly. It did not. Here is the error message I received:

Error: Package: dnf-0.4.2-1.gitc1716d7.fc20.noarch (updates-testing)
           Requires: python-librepo = 1.2.0
           Available: python-librepo-1.0.0-1.fc20.x86_64 (fedora)
               python-librepo = 1.0.0-1.fc20
           Available: python-librepo-1.2.1-1.fc20.x86_64 (updates-testing)
               python-librepo = 1.2.1-1.fc20
 You could try using --skip-broken to work around the problem
** Found 1 pre-existing rpmdb problem(s), 'yum check' output follows:
kde-settings-kdm-19-23.1.fc19.noarch is a duplicate with kde-settings-kdm-19-23.fc19.noarch