The updates-testing repository, also referred to as Test Updates, contains updates scheduled to be released for Branched pre-releases (after the Bodhi enabling point) and stable releases of Fedora. User testing and feedback provided via Bodhi, on the test mailing list and the relevant Bugzilla is vital to ensure that good updates are released quickly and bad ones kept away from release.
Using the updates-testing repository
Enabling the repository permanently
With dnf (Fedora 22 and later):
dnf config-manager --set-enabled updates-testing
Use or dnf repolist to verify. To disable the repository again, with dnf (Fedora 22 and later):
dnf config-manager --set-disabled updates-testing
dnf distro-sync will sync the packages to the versions available in the repository and might be useful to run after you disable the testing repository to downgrade packages back to the stable versions.Note that the dnf config-manager command is available as part of the 
dnf-plugins-core
Enabling the repository temporarily
If you'd rather not enable the updates-testing repository permanently but just use it on a case-by-case basis, you can do this with dnf. On Fedora 22 or later, use the command:
dnf update --enablerepo=updates-testing
will update the entire system using packages from the updates-testing repository, while the command:
dnf install <foo> --enablerepo=updates-testing
will install or update only the package named <foo> from the updates-testing repository.
Testing updates for EPEL with CentOS or RHEL
CentOS and RHEL use yum instead of DNF, but the basic procedure for installing a particular test update for EPEL is similar:
yum install <foo> --enablerepo=epel-testing
will install or update only the package named <foo> from the epel-testing repository.
Using it with Atomic Host (Fedora 26 and later)
Note these "refs" or branches are for Fedora 27 Atomic Host; if you're using 26, replace the 27 below.
rpm-ostree rebase fedora/27/x86_64/testing/atomic-host
Going back to master:
rpm-ostree rebase fedora/27/x86_64/atomic-host
NOTE: If you see fsetxattr: Invalid argument, see: https://bugzilla.redhat.com/show_bug.cgi?id=1309075#c30
What to test, testing, and reporting results
The Bodhi system is used to track and collate feedback on testing updates. All testing updates will be shown in the Bodhi system. The update feedback guidelines explain what feedback you should leave in what situations, based on your testing of the package.
In the web interface, each Works for me adds 1 to the test update's karma, while each Does not work subtracts 1 from it. Untested leaves the karma unchanged. Other tools present this in different ways, but the +1/-1/0 mechanism is the same.
By default, test updates with karma of 3 are automatically sent out as full official updates, while test updates with karma of -3 are automatically withdrawn from the testing repository. The Updates Policy specifies minimum levels of karma that different types of update must meet at different points in the development cycle. As you can see, your testing and feedback is vital to make sure that good updates are released quickly and bad ones don't get out to the general public.
For pre-releases, karma may be required for important package builds to become a part of the final release. Look out for mails to the test-announce mailing list requesting karma for specific builds.
Using fedora-easy-karma
There is a tool you can use to ease the process of reporting your feedback, called
After installation, you can launch the tool at any time by running fedora-easy-karma in a console. If your FAS account name is not the same as your user name, use the --fas-username parameter to specify your FAS account name. It will automatically discover what packages, if any, you currently have installed from the updates-testing repository, and let you file your feedback before moving on to the next package, all in one linear process.
Using the web interface
You can also give your feedback on a test update by using the Bodhi web interface. There is a Login link in the left-hand sidebar. Log in using your Fedora account. If you don't have a Fedora account, you can create an account here. Once you are logged in, you will be able to leave a comment on the update. To the right of the comment box are three radio button options that effect karma, represented by three icons that depict FAIL, Untested and PASS. The label for these options asks "Is the update generally functional?"
The icon on the left (which looks like an X) represents "FAIL - Does not fix the bug or pass the test case." The middle option (shaped like an open box) indicates "Untested". And the rightmost icon (which looks like a check mark) designates "PASS - Fixes the bug or passes the test case." These options will leave -1, 0, or +1 karma respectively for the update.
Note on using DNF with updates-testing and dependency errors
If you use the DNF tool rather than yum, note that unlike yum, it does not notify you of dependency errors in the set of available updates by default. yum will, by default, print some information about the dependency errors, and then fail the update: you have to run yum update --skip-broken to install all the updates that do not have dependency errors. DNF essentially does --skip-broken by default, and silently - it will install all updates that do not have dependency errors, and not tell you about those that do.
To use dnf to spot updates with dependency errors, you can run dnf update --best, which should act like yum's default behaviour.
Updates-testing enabled by default in development (Branched) releases
In Fedora Branched releases - the next release, once it has branched from Rawhide, but before it is released - the updates-testing repository is enabled by default. Package maintainers in Fedora are encouraged to test their updates via this repository first to keep the development branch more robust while providing the latest updates. If you are a tester, it is recommended to leave this repository enabled and provide feedback to help make the general release that follows a robust one. In the development branch, packages that are in the updates-testing repository will move into the base repository when approved, not the updates repository.
Before release, a fedora-release update will automatically disable the updates-testing repository and enable the updates repository. After the general release, the updates repository will start filling up as more updates gets pushed through but until the release time, updates repository will remain empty.