32 Performing Automated Runtime Testing

The OpenEmbedded build system makes available a series of automated tests for images to verify runtime functionality. You can run these tests on either QEMU or actual target hardware. Tests are written in Python making use of the unittest module, and the majority of them run commands on the target system over SSH. This section describes how you set up the environment to use these tests, run available tests, and write and add your own tests.

For information on the test and QA infrastructure available within the Yocto Project, see the “Testing and Quality Assurance” section in the Yocto Project Reference Manual.

32.1 Enabling Tests

Depending on whether you are planning to run tests using QEMU or on the hardware, you have to take different steps to enable the tests. See the following subsections for information on how to enable both types of tests.

32.1.1 Enabling Runtime Tests on QEMU

In order to run tests, you need to do the following:

  • Set up to avoid interaction with sudo for networking: To accomplish this, you must do one of the following:

    • Add NOPASSWD for your user in /etc/sudoers either for all commands or just for runqemu-ifup. You must provide the full path as that can change if you are using multiple clones of the source repository.


      On some distributions, you also need to comment out “Defaults requiretty” in /etc/sudoers.

    • Manually configure a tap interface for your system.

    • Run as root the script in scripts/runqemu-gen-tapdevs, which should generate a list of tap devices. This is the option typically chosen for Autobuilder-type environments.


      • Be sure to use an absolute path when calling this script with sudo.

      • Ensure that your host has the package iptables installed.

      • The package recipe qemu-helper-native is required to run this script. Build the package using the following command:

        $ bitbake qemu-helper-native
  • Set the DISPLAY variable: You need to set this variable so that you have an X server available (e.g. start vncserver for a headless machine).

  • Be sure your host’s firewall accepts incoming connections from Some of the tests (in particular DNF tests) start an HTTP server on a random high number port, which is used to serve files to the target. The DNF module serves ${WORKDIR}/oe-rootfs-repo so it can run DNF channel commands. That means your host’s firewall must accept incoming connections from, which is the default IP range used for tap devices by runqemu.

  • Be sure your host has the correct packages installed: Depending your host’s distribution, you need to have the following packages installed:

    • Ubuntu and Debian: sysstat and iproute2

    • openSUSE: sysstat and iproute2

    • Fedora: sysstat and iproute

    • CentOS: sysstat and iproute

Once you start running the tests, the following happens:

  1. A copy of the root filesystem is written to ${WORKDIR}/testimage.

  2. The image is booted under QEMU using the standard runqemu script.

  3. A default timeout of 500 seconds occurs to allow for the boot process to reach the login prompt. You can change the timeout period by setting TEST_QEMUBOOT_TIMEOUT in the local.conf file.

  4. Once the boot process is reached and the login prompt appears, the tests run. The full boot log is written to ${WORKDIR}/testimage/qemu_boot_log.

  5. Each test module loads in the order found in TEST_SUITES. You can find the full output of the commands run over SSH in ${WORKDIR}/testimgage/ssh_target_log.

  6. If no failures occur, the task running the tests ends successfully. You can find the output from the unittest in the task log at ${WORKDIR}/temp/log.do_testimage.

32.1.2 Enabling Runtime Tests on Hardware

The OpenEmbedded build system can run tests on real hardware, and for certain devices it can also deploy the image to be tested onto the device beforehand.

For automated deployment, a “controller image” is installed onto the hardware once as part of setup. Then, each time tests are to be run, the following occurs:

  1. The controller image is booted into and used to write the image to be tested to a second partition.

  2. The device is then rebooted using an external script that you need to provide.

  3. The device boots into the image to be tested.

When running tests (independent of whether the image has been deployed automatically or not), the device is expected to be connected to a network on a pre-determined IP address. You can either use static IP addresses written into the image, or set the image to use DHCP and have your DHCP server on the test network assign a known IP address based on the MAC address of the device.

In order to run tests on hardware, you need to set TEST_TARGET to an appropriate value. For QEMU, you do not have to change anything, the default value is “qemu”. For running tests on hardware, the following options are available:

  • “simpleremote”: Choose “simpleremote” if you are going to run tests on a target system that is already running the image to be tested and is available on the network. You can use “simpleremote” in conjunction with either real hardware or an image running within a separately started QEMU or any other virtual machine manager.

  • “SystemdbootTarget”: Choose “SystemdbootTarget” if your hardware is an EFI-based machine with systemd-boot as bootloader and core-image-testmaster (or something similar) is installed. Also, your hardware under test must be in a DHCP-enabled network that gives it the same IP address for each reboot.

    If you choose “SystemdbootTarget”, there are additional requirements and considerations. See the “Selecting SystemdbootTarget” section, which follows, for more information.

  • “BeagleBoneTarget”: Choose “BeagleBoneTarget” if you are deploying images and running tests on the BeagleBone “Black” or original “White” hardware. For information on how to use these tests, see the comments at the top of the BeagleBoneTarget meta-yocto-bsp/lib/oeqa/controllers/beaglebonetarget.py file.

  • “GrubTarget”: Choose “GrubTarget” if you are deploying images and running tests on any generic PC that boots using GRUB. For information on how to use these tests, see the comments at the top of the GrubTarget meta-yocto-bsp/lib/oeqa/controllers/grubtarget.py file.

  • “your-target”: Create your own custom target if you want to run tests when you are deploying images and running tests on a custom machine within your BSP layer. To do this, you need to add a Python unit that defines the target class under lib/oeqa/controllers/ within your layer. You must also provide an empty __init__.py. For examples, see files in meta-yocto-bsp/lib/oeqa/controllers/.

32.1.3 Selecting SystemdbootTarget

If you did not set TEST_TARGET to “SystemdbootTarget”, then you do not need any information in this section. You can skip down to the “Running Tests” section.

If you did set TEST_TARGET to “SystemdbootTarget”, you also need to perform a one-time setup of your controller image by doing the following:

  1. Set EFI_PROVIDER: Be sure that EFI_PROVIDER is as follows:

    EFI_PROVIDER = "systemd-boot"
  2. Build the controller image: Build the core-image-testmaster image. The core-image-testmaster recipe is provided as an example for a “controller” image and you can customize the image recipe as you would any other recipe.

    Image recipe requirements are:

    • Inherits core-image so that kernel modules are installed.

    • Installs normal linux utilities not BusyBox ones (e.g. bash, coreutils, tar, gzip, and kmod).

    • Uses a custom Initramfs image with a custom installer. A normal image that you can install usually creates a single root filesystem partition. This image uses another installer that creates a specific partition layout. Not all Board Support Packages (BSPs) can use an installer. For such cases, you need to manually create the following partition layout on the target:

      • First partition mounted under /boot, labeled “boot”.

      • The main root filesystem partition where this image gets installed, which is mounted under /.

      • Another partition labeled “testrootfs” where test images get deployed.

  3. Install image: Install the image that you just built on the target system.

The final thing you need to do when setting TEST_TARGET to “SystemdbootTarget” is to set up the test image:

  1. Set up your local.conf file: Make sure you have the following statements in your local.conf file:

    IMAGE_FSTYPES += "tar.gz"
    IMAGE_CLASSES += "testimage"
    TEST_TARGET = "SystemdbootTarget"
  2. Build your test image: Use BitBake to build the image:

    $ bitbake core-image-sato

32.1.4 Power Control

For most hardware targets other than “simpleremote”, you can control power:

  • You can use TEST_POWERCONTROL_CMD together with TEST_POWERCONTROL_EXTRA_ARGS as a command that runs on the host and does power cycling. The test code passes one argument to that command: off, on or cycle (off then on). Here is an example that could appear in your local.conf file:

    TEST_POWERCONTROL_CMD = "powercontrol.exp test nuc1"

    In this example, the expect script does the following:

    ssh test@ "pyctl nuc1 arg"

    It then runs a Python script that controls power for a label called nuc1.


    You need to customize TEST_POWERCONTROL_CMD and TEST_POWERCONTROL_EXTRA_ARGS for your own setup. The one requirement is that it accepts “on”, “off”, and “cycle” as the last argument.

  • When no command is defined, it connects to the device over SSH and uses the classic reboot command to reboot the device. Classic reboot is fine as long as the machine actually reboots (i.e. the SSH test has not failed). It is useful for scenarios where you have a simple setup, typically with a single board, and where some manual interaction is okay from time to time.

If you have no hardware to automatically perform power control but still wish to experiment with automated hardware testing, you can use the dialog-power-control script that shows a dialog prompting you to perform the required power action. This script requires either KDialog or Zenity to be installed. To use this script, set the TEST_POWERCONTROL_CMD variable as follows:

TEST_POWERCONTROL_CMD = "${COREBASE}/scripts/contrib/dialog-power-control"

32.1.5 Serial Console Connection

For test target classes requiring a serial console to interact with the bootloader (e.g. BeagleBoneTarget and GrubTarget), you need to specify a command to use to connect to the serial console of the target machine by using the TEST_SERIALCONTROL_CMD variable and optionally the TEST_SERIALCONTROL_EXTRA_ARGS variable.

These cases could be a serial terminal program if the machine is connected to a local serial port, or a telnet or ssh command connecting to a remote console server. Regardless of the case, the command simply needs to connect to the serial console and forward that connection to standard input and output as any normal terminal program does. For example, to use the picocom terminal program on serial device /dev/ttyUSB0 at 115200bps, you would set the variable as follows:

TEST_SERIALCONTROL_CMD = "picocom /dev/ttyUSB0 -b 115200"

For local devices where the serial port device disappears when the device reboots, an additional “serdevtry” wrapper script is provided. To use this wrapper, simply prefix the terminal command with ${COREBASE}/scripts/contrib/serdevtry:

TEST_SERIALCONTROL_CMD = "${COREBASE}/scripts/contrib/serdevtry picocom -b 115200 /dev/ttyUSB0"

32.2 Running Tests

You can start the tests automatically or manually:

  • Automatically running tests: To run the tests automatically after the OpenEmbedded build system successfully creates an image, first set the TESTIMAGE_AUTO variable to “1” in your local.conf file in the Build Directory:


    Next, build your image. If the image successfully builds, the tests run:

    bitbake core-image-sato
  • Manually running tests: To manually run the tests, first globally inherit the testimage class by editing your local.conf file:

    IMAGE_CLASSES += "testimage"

    Next, use BitBake to run the tests:

    bitbake -c testimage image

All test files reside in meta/lib/oeqa/runtime/cases in the Source Directory. A test name maps directly to a Python module. Each test module may contain a number of individual tests. Tests are usually grouped together by the area tested (e.g tests for systemd reside in meta/lib/oeqa/runtime/cases/systemd.py).

You can add tests to any layer provided you place them in the proper area and you extend BBPATH in the local.conf file as normal. Be sure that tests reside in layer/lib/oeqa/runtime/cases.


Be sure that module names do not collide with module names used in the default set of test modules in meta/lib/oeqa/runtime/cases.

You can change the set of tests run by appending or overriding TEST_SUITES variable in local.conf. Each name in TEST_SUITES represents a required test for the image. Test modules named within TEST_SUITES cannot be skipped even if a test is not suitable for an image (e.g. running the RPM tests on an image without rpm). Appending “auto” to TEST_SUITES causes the build system to try to run all tests that are suitable for the image (i.e. each test module may elect to skip itself).

The order you list tests in TEST_SUITES is important and influences test dependencies. Consequently, tests that depend on other tests should be added after the test on which they depend. For example, since the ssh test depends on the ping test, “ssh” needs to come after “ping” in the list. The test class provides no re-ordering or dependency handling.


Each module can have multiple classes with multiple test methods. And, Python unittest rules apply.

Here are some things to keep in mind when running tests:

  • The default tests for the image are defined as:

    DEFAULT_TEST_SUITES:pn-image = "ping ssh df connman syslog xorg scp vnc date rpm dnf dmesg"
  • Add your own test to the list of the by using the following:

    TEST_SUITES:append = " mytest"
  • Run a specific list of tests as follows:

    TEST_SUITES = "test1 test2 test3"

    Remember, order is important. Be sure to place a test that is dependent on another test later in the order.

32.3 Exporting Tests

You can export tests so that they can run independently of the build system. Exporting tests is required if you want to be able to hand the test execution off to a scheduler. You can only export tests that are defined in TEST_SUITES.

If your image is already built, make sure the following are set in your local.conf file:

INHERIT += "testexport"
TEST_TARGET_IP = "IP-address-for-the-test-target"
TEST_SERVER_IP = "IP-address-for-the-test-server"

You can then export the tests with the following BitBake command form:

$ bitbake image -c testexport

Exporting the tests places them in the Build Directory in tmp/testexport/image, which is controlled by the TEST_EXPORT_DIR variable.

You can now run the tests outside of the build environment:

$ cd tmp/testexport/image
$ ./runexported.py testdata.json

Here is a complete example that shows IP addresses and uses the core-image-sato image:

INHERIT += "testexport"

Use BitBake to export the tests:

$ bitbake core-image-sato -c testexport

Run the tests outside of the build environment using the following:

$ cd tmp/testexport/core-image-sato
$ ./runexported.py testdata.json

32.4 Writing New Tests

As mentioned previously, all new test files need to be in the proper place for the build system to find them. New tests for additional functionality outside of the core should be added to the layer that adds the functionality, in layer/lib/oeqa/runtime/cases (as long as BBPATH is extended in the layer’s layer.conf file as normal). Just remember the following:

  • Filenames need to map directly to test (module) names.

  • Do not use module names that collide with existing core tests.

  • Minimally, an empty __init__.py file must be present in the runtime directory.

To create a new test, start by copying an existing module (e.g. oe_syslog.py or gcc.py are good ones to use). Test modules can use code from meta/lib/oeqa/utils, which are helper classes.


Structure shell commands such that you rely on them and they return a single code for success. Be aware that sometimes you will need to parse the output. See the df.py and date.py modules for examples.

You will notice that all test classes inherit oeRuntimeTest, which is found in meta/lib/oetest.py. This base class offers some helper attributes, which are described in the following sections:

32.4.1 Class Methods

Class methods are as follows:

  • hasPackage(pkg): Returns “True” if pkg is in the installed package list of the image, which is based on the manifest file that is generated during the do_rootfs task.

  • hasFeature(feature): Returns “True” if the feature is in IMAGE_FEATURES or DISTRO_FEATURES.

32.4.2 Class Attributes

Class attributes are as follows:

  • pscmd: Equals “ps -ef” if procps is installed in the image. Otherwise, pscmd equals “ps” (busybox).

  • tc: The called test context, which gives access to the following attributes:

    • d: The BitBake datastore, which allows you to use stuff such as oeRuntimeTest.tc.d.getVar("VIRTUAL-RUNTIME_init_manager").

    • testslist and testsrequired: Used internally. The tests do not need these.

    • filesdir: The absolute path to meta/lib/oeqa/runtime/files, which contains helper files for tests meant for copying on the target such as small files written in C for compilation.

    • target: The target controller object used to deploy and start an image on a particular target (e.g. Qemu, SimpleRemote, and SystemdbootTarget). Tests usually use the following:

      • ip: The target’s IP address.

      • server_ip: The host’s IP address, which is usually used by the DNF test suite.

      • run(cmd, timeout=None): The single, most used method. This command is a wrapper for: ssh root@host "cmd". The command returns a tuple: (status, output), which are what their names imply - the return code of “cmd” and whatever output it produces. The optional timeout argument represents the number of seconds the test should wait for “cmd” to return. If the argument is “None”, the test uses the default instance’s timeout period, which is 300 seconds. If the argument is “0”, the test runs until the command returns.

      • copy_to(localpath, remotepath): scp localpath root@ip:remotepath.

      • copy_from(remotepath, localpath): scp root@host:remotepath localpath.

32.4.3 Instance Attributes

There is a single instance attribute, which is target. The target instance attribute is identical to the class attribute of the same name, which is described in the previous section. This attribute exists as both an instance and class attribute so tests can use self.target.run(cmd) in instance methods instead of oeRuntimeTest.tc.target.run(cmd).

32.5 Installing Packages in the DUT Without the Package Manager

When a test requires a package built by BitBake, it is possible to install that package. Installing the package does not require a package manager be installed in the device under test (DUT). It does, however, require an SSH connection and the target must be using the sshcontrol class.


This method uses scp to copy files from the host to the target, which causes permissions and special attributes to be lost.

A JSON file is used to define the packages needed by a test. This file must be in the same path as the file used to define the tests. Furthermore, the filename must map directly to the test module name with a .json extension.

The JSON file must include an object with the test name as keys of an object or an array. This object (or array of objects) uses the following data:

  • “pkg” — a mandatory string that is the name of the package to be installed.

  • “rm” — an optional boolean, which defaults to “false”, that specifies to remove the package after the test.

  • “extract” — an optional boolean, which defaults to “false”, that specifies if the package must be extracted from the package format. When set to “true”, the package is not automatically installed into the DUT.

Here is an example JSON file that handles test “foo” installing package “bar” and test “foobar” installing packages “foo” and “bar”. Once the test is complete, the packages are removed from the DUT:

    "foo": {
        "pkg": "bar"
    "foobar": [
            "pkg": "foo",
            "rm": true
            "pkg": "bar",
            "rm": true