Tast Test Dependencies (go/tast-deps)

A test may specify software or hardware features that must be supported on the DUT in order for the test to run successfully. If one or more features aren‘t supported by the DUT, the test will usually be skipped. See the tast command’s -checktestdeps flag to control this behavior.

Tests specify dependencies through the SoftwareDeps and HardwareDeps fields in testing.Test.

Software dependencies

Existing features

The following software features are defined:

  • amd64 - The amd64 processor architecture.
  • amd_cpu - Boards that contain an AMD application processor.
  • android_container - The ability to run Android apps in a container instead of a VM. Prefer this over android_container_r if possible.
  • android_container_r - android_container features that runs in R container.
  • android_vm - The ability to run Android apps in VM instead of container. Any version of Android R+ can be used. Prefer this over android_vm_r if possible.
  • android_vm_r - android_vm feature that runs in R VM.
  • android_p - The ability to run Android apps that require Android P.
  • android_r - The ability to run Android apps that require Android R.
  • arc - The ability to run Android apps in any way, in VM or container, with any Android version. This is intended to be used to run non-ARC tests only when ARC is supported on the board.
  • arc32 - Runs 32-bit Android primary ABI.
  • arc64 - Runs 64-bit Android primary ABI, may or may not have 32-bit support.
  • arc_android_data_cros_access - The ability to access Android‘s /data directory from ChromeOS. For ARCVM virtio-blk /data devices, this only ensures that we can mount the virtio-blk disk image of Android’s /data directory on the host, and does not grant an automatic access to Android's /data directory from the host side.
  • arc_camera3 - Using Camera HAL3 interface in Chrome and Android.
  • arc_launched_32bit - This platform originally launched with 32-bit Android.
  • arc_launched_64bit - This platform originally launched with 64-bit Android.
  • arm - The arm 32 and 64 bit processor architecture.
  • aslr - Address space layout randomization, which mitigates buffer-overflow attacks, is functional (this is not true for builds with AddressSanitizer instrumentation built in).
  • auto_update_stable - No suffix like -kernelnext and -arc-r in the board name. Auto update to a stable version is possible.
  • autotest-capability:foo - An Autotest capability named foo. See below.
  • biometrics_daemon - The ability to process fingerprint authentication. This implies the presence of the biod package.
  • bluetooth_floss - Excludes boards that do not support the floss bluetooth adapter.
  • boot_perf_info - Reven (ChromeOS Flex) doesn't support boot performance metrics.
  • borealis_host - Boards that can host the Borealis system.
  • borealis_nvidia - Boards that use nvidia supported Borealis system.
  • bpf - Whether the platform (kernel) has the bpf syscall enabled.
  • breakpad - Whether the platform supports the breakpad crash handler for Chrome.
  • camera_720p - The ability to capture video with frame size 1280x720.
  • camera_app - The ability to run the builtin camera app.
  • camera_feature_auto_framing - Whether Auto Framing is enabled on this platform.
  • camera_feature_effects - Whether camera effects are enabled on this platform.
  • camera_feature_hdrnet - Whether HDRnet is enabled on this platform.
  • camera_feature_portrait_mode - Whether Portrait Mode is enabled on this platform.
  • cert_provision - The ability to use an additional cert_provision library that supports an interface for provisioning machine-wide certificates and using them for signing data on top of cryptohome dbus interface.
  • chrome - Support for performing user login via Chrome (i.e. using session_manager and cryptohome). This also implies that the chromeos-chrome Portage package is installed (which also installs Chrome binary tests), and that the ui Upstart job is present.
  • chromeless - Explicit lack of support for login via Chrome.
  • chromeos_firmware - Boards that use ChromeOS firmware.
  • chromeos_kernelci - Whether the image built for https://chromeos.kernelci.org/ or not.
  • chrome_internal - Functionality that is only available in internal builds of Chrome (e.g. official branding). Any test that specifies this dependency should also explicitly specify a chrome dependency.
  • coresched - Whether device supports core scheduling feature for secure HT.
  • cpuidle_teo - Availability of the TEO cpuidle governor.
  • cpu_heterogeneous - Whether device has heterogeneous CPU topology.
  • cpu_vuln_sysfs - Whether the platform has /sys/devices/system/cpu/vulnerabilities sysfs files
  • cras - Whether the platform supports the ChromeOS Audio Server.
  • crashpad - Whether the platform supports the crashpad crash handler for Chrome.
  • cros_internal - Functionality that is only available in internal builds of ChromeOS (i.e. ones built using chromeos-overlay).
  • crossystem - ChromeOS firmware/system interface utility.
  • crostini_stable - Boards that can run Crostini tests reliably.
  • crostini_unstable - Boards that cannot run Crostini tests reliably.
  • crosvm_gpu - Boards that use hardware GPU acceleration in the guest VM environment.
  • crosvm_no_gpu - Boards that use software GPU emulation in the guest VM environment.
  • crosvm_swap - Boards that have crosvm's vmm-swap feature enabled.
  • csme_update - Intel boards with updateable CSME firmware (volteer/dedede onwards)
  • cups - CUPS daemon.
  • device_crash - Boards that can recover gracefully after a hard crash (e.g. kernel crash)
  • diagnostics - Boards that contain generic cross-platform Diagnostic utilities.
  • dlc - Support of Downloadable Content (DLC).
  • dmverity_stable - Kernels with which dm-verity runs stably. See b/172227689.
  • dmverity_unstable - Kernels having known issue of dm-verity causing random crashes. See b/172227689.
  • dptf - Support of Intel Dynamic Platform and Thermal Framework (DPTF).
  • drivefs - Google Drive support enabled.
  • drm_atomic - The DRM/KMS kernel subsystem supports atomic commits.
  • drm_trace - The DRM/KMS kernel subsystem supports tracing using tracefs.
  • ec_crash - Boards that have EC firmware, implement the crash EC command, and produce a panicinfo file after a crash.
  • endorsement - Whether the system have a valid endorsement certificate.
  • faceauth - Whether the system has faceauth functionality enabled, go/cros-faceauth.
  • factory_flow- Device is subject to the go/chromeos-factory-flow (e.g. most devices).
  • fake_hps - Whether the HPS daemon (go/cros-hps) uses a fake software device for testing purposes.
  • firewall - Standard ChromeOS network firewall rules.
  • flashrom - Userspace utility to update firmware.
  • flex_id - Enable using flex_id for enrollment.
  • flex_internal - Enable using flex_internal to pull in data (URLs, API keys, etc.) only needed by official Flex releases.
  • ghostscript - Ghostscript and dependent packages are available for printing.
  • google_virtual_keyboard - The proprietary Google onscreen virtual keyboard (as opposed to the builtin open-source virtual keyboard).
  • gpu_sandboxing - Chrome's GPU process is sandboxed.
  • gsc - Whether the platform has an onboard Google security chip.
  • has_recovery_mrc_cache - Boards that have the RECOVERY_MRC_CACHE section.
  • hibernate- Whether the platform supports hibernate.
  • houdini - Availability of 32-bit Houdini library for ARC.
  • houdini64 - Availability of 64-bit Houdini library for ARC.
  • hostap_hwsim - Whether system has the hostap project's test dependencies (scripts, daemons) installed and configured appropriately.
  • hps - Whether the system has the hps daemon and tools, go/cros-hps.
  • igt - Boards that can run igt-gpu-tools tests
  • iioservice - Whether the device has CrOS IIO Service running.
  • inference_accuracy_eval - Whether the device has inference accuracy evaluation tools installed.
  • intel_psr - Whether Intel PSR (platform service record) is supported or not.
  • ikev2 - The ability to run an IKEv2 VPN.
  • io_uring - Whether the platform (kernel) has the io_uring syscalls enabled.
  • iwlwifi_rescan - Ability to remove/rescan WiFi PCI device when the hardware becomes non-responsive.
  • known_fixed_ssd - Set when the fixed SSD location globs are defined. They are not for board:reven (the hardware is not fixed) and VMs, since the path is either not defined (if taken directly from xxx-generic overlay) or already defined to real hardware location. Only for betty we do defined a “hardware” path since that board is only used for VM.
  • lacros - Whether the system supports running lacros.
  • lacros_stable - Whether the system supports running lacros and is stable enough for CQ. TODO: Remove this.
  • lacros_unstable - Whether the system supports running lacros and is not stable enough for CQ. TODO: Remove this.
  • landlock_enabled - Whether the system supports the Landlock Linux Security Module.
  • mbo - WiFi MBO support.
  • memfd_create - memfd_create function implemented in the kernel.
  • memd - Memory stats collection daemon.
  • microcode - Platforms that have CPU microcode.
  • ml_benchmark_drivers - ML benchmarking suite
  • ml_service - ML Service daemon.
  • ml_tiered_support - Platforms enabled for tiered benchmarking.
  • mosys - Ability to run mosys command.
  • nacl - Availability of the Native Client sandboxing technology.
  • ndk_translation - Availability of 32-bit NDK translation library for ARC.
  • ndk_translation64 - Availability of 64-bit NDK translation library for ARC.
  • nnapi - Has the nnapi (libneuralnetworks.so) installed. Run minimal VTS tests.
  • nnapi_vendor_driver - Run the full VTS / CTS test suite. Ignores VM's.
  • no_android - The inability to run Android apps. This is the opposite of the android feature; DUTs will have exactly one of these two features.
  • no_arm - The absence of arm 32 bit userspace.
  • no_asan - Build was not built with Address Sanitizer. Similar to aslr.
  • no_borealis_host - Boards which is not designed to host borealis.
  • no_chrome_dcheck - Chrome/Chromium was not built with dcheck enabld.
  • no_eth_loss_on_reboot - Board does not lose ethernet on reboot. Context: b/178529170
  • no_iioservice - Build was not built with CrOS IIO Service.
  • no_msan - Build was not built with Memory Sanitizer.
  • no_ondevice_handwriting - Doesn‘t have on-device handwriting recognition support. Either ml_service is not enabled, or if ml_service doesn’t support ondevice_handwriting.
  • no_arc_userdebug - Skip boards that ship ARC userdebug build.
  • no_arc_x86 - Skip on x86 architecture.
  • no_qemu - For tests not for ChromeOS QEMU images.
  • no_symlink_mount - Symlink mounting is disabled via the CONFIG_SECURITY_CHROMIUMOS_NO_SYMLINK_MOUNT kernel option.
  • no_tablet_form_factor - The device's primary form factor is not tablet
  • no_tpm2_simulator - Built was not built with the simulator of Trusted Platform Module supporting TPMv2.
  • no_tpm_dynamic - Build was not built with dynamic TPM.
  • no_ubsan - Build was not built with Undefined Behavior Sanitizer.
  • no_vulkan - Build was not built with Vulkan enabled.
  • no_arcvm_virtio_blk_data - Build was not built with ARCVM virtio-blk /data enabled.
  • no_gsc - Build was not built with onboard Google security chip support.
  • nmi_backtrace - The Linux kernel has support for NMI backtraces.
  • nvme - Ability to run NVMe software utilities.
  • oci - The ability to use the run_oci program to execute code within OCI containers.
  • ocr - Optical Character Recognition Service daemon.
  • ondevice_document_scanner - On-device document scanner support in ml_service which installed document scanner library in rootfs. This implies ml_service.
  • ondevice_document_scanner_rootfs_or_dlc - On-device document scanner support in ml_service. This implies ml_service.
  • ondevice_grammar - On-device grammar check support in ml_service.
  • ondevice_handwriting - On-device handwriting recognition support in ml_service.
  • ondevice_image_content_annotation - On-device image content annotation support in ml_service.
  • ondevice_speech - On-device speech recognition support in ml_service.
  • ondevice_text_suggestions - On-device txt suggestions support in ml_service.
  • pinweaver - Pinweaver support, either by GSC or Intel CSME. This implies ml_service.
  • play_store - Boards where Google Play Store is supported.
  • plugin_vm - The ability to run Plugin VMs.
  • proprietary_codecs - Indicates if Chrome supports proprietary video codecs (e.g. H.264). This is supported by Chrome official builds and Chromium builds with the |propietary_codecs| build flag set.
  • protected_content - Platform has HW backed OEMCrypto implementation for Widevine L1 HW DRM.
  • qemu - For tests exclusive to ChromeOS QEMU images.
  • racc - Whether Runtime AVL Compliance Check is available.
  • reboot - The ability to reboot reliably during a remote test.
  • screenshot - The screenshot command can save screenshots.
  • selinux - An SELinux-enabled board. All Android boards are SELinux-enabled.
  • selinux_current - All SELinux-enabled boards except experimental boards. This implies selinux.
  • selinux_experimental - An experimental SELinux board. An experimental board has SELINUX=permissive in /etc/selinux/config, thus no policy will be enforced. This implies selinux.
  • shill-wifi - WiFi technology is enabled for Shill.
  • shipping_kernel - Debug-related kernel configs are not enabled.
  • smartdim - Use smart dim to defer the imminent screen dimming.
  • smartctl - Ability to run smartctl software utility.
  • stack_sampled_metrics - Ability to run the stack profiler and gather stack-sampled metrics.
  • storage_wearout_detect - The ability to measure storage device health.
  • tablet_form_factor - The device's primary form factor is tablet
  • tast_vm - The test is running in a VM managed by chromite.
  • tflite_opencl - Skips boards which have issues with the OpenCL TFLite delegate (b/233851820).
  • thread_safe_libva_backend - Boards where the LIBVA backend is threadsafe.
  • tpm - A Trusted Platform Module chip.
  • tpm_clear_allowed - The device's TPM can be cleared.
  • tpm1 - Indicate a Trusted Platform Module supporting TPMv1.2 is available. Note that TPMv2 is not backward compatible.
  • tpm2 - Indicate a Trusted Platform Module supporting TPMv2 is available.
  • tpm2_simulator - Indicate the simulator of Trusted Platform Module supporting TPMv2 is available.
  • tpm_dynamic - Indicate the dynamic TPM is available.
  • transparent_hugepage - Transparent Hugepage support in the Linux kernel.
  • unibuild - The ChromeOS build is a unified build.
  • untrusted_vm - The ability to run an untrusted VM.
  • usbguard - The ability to allow or block USB devices based on policy.
  • usb_hid_wake - The platform will register HID wake events to a usb device.
  • use_fscrypt_v1 - The board is set to use v1 fscrypt policy for user vault.
  • use_fscrypt_v2 - The board is set to use v2 fscrypt policy for user vault.
  • uvc_compliant - The board has a UVC driver that is V4L2 compliant.
  • v4l2_codec - Whether or not v4l2 video acceleration API is supported by this DUT.
  • vaapi - Whether or not VA-API is supported by this DUT.
  • video_cards_ihd - Boards that use the Intel Media Driver (also known as iHD) for VA-API.
  • video_decoder_direct - The platform uses the VideoDecoder (VD) by default.
  • video_decoder_legacy - The platform used the VideoDecodeAccelerator (VDA) by default.
  • video_decoder_legacy_supported - Is the VDA is supported on this platform.
  • video_overlays - The kernel DRM/KMS version atomic commits and the underlying hardware display controller support the NV12 DRM Plane format needed to promote videos to hardware overlays.
  • virtual_multidisplay - The platform supports virtual multi display testing (at the time of writing, only 6.1+ betty boards). This should be depended on for all multidisplay presubmit tests to run on betty.
  • virtual_susupend_time_injection - The platform supports KVM virtual suspend time injection.
  • vm_host - The ability to run virtual machines.
  • vpd - The DUT has a VPD chip.
  • vulkan - Whether Vulkan libraries are installed on the system image.
  • vulkan_composite - Boards that support composition with Vulkan.
  • watchdog - watchdog daemon
  • wifi - If this DUT has WiFi device.
  • wpa3_sae - The ability to use WPA3-SAE authentication for WiFi.
  • wilco - If this DUT is a wilco device. These features include the DTC (Diagnostic and Telemetry Controller) VM, a special EC interface, and a dock firmware updater.
  • wireguard - The ability to run a WireGuard VPN.
  • no_kernel_upstream - Skip boards with continuously-rebased kernel.

New features

Features should be descriptive and precise. Consider a hypothetical test that exercises authentication using a biometrics daemon that isn‘t present in system images built to run on virtual machines. Instead of adding a real_hardware or non_vm feature that is overly broad and will likely be interpreted as carrying additional meaning beyond the original intent, add a biometrics_daemon feature that precisely communicates the test’s actual requirement.

Features are composed from USE flags and board names, which are statically defined when the system image is built. As an example, the USE flags for Brya devices are defined in make.defaults. software_defs.go lists boolean expressions that are used to generate features; for example, an imaginary feature named hd_audio with the expression

cras && (audio_chipset_a || audio_chipset_b) && !broken_headphone_jack

will be reported as available on systems where the cras USE flag is set, either audio_chipset_a or audio_chipset_b is set, and broken_headphone_jack is explicitly not set.

A feature can depend on board names, too. Another imaginary feature named vm_graphics with the expression


will be reported as available on betty-pi-arc board only.

Before a new USE flag can be used in an expression, it must be added to IUSE in the tast-use-flags package. Local changes to the tast-use-flags ebuild have to be pushed to the DUT manually to take effect:

cros_workon-$BOARD start chromeos-base/tast-use-flags
emerge-$BOARD chromeos-base/tast-use-flags
cros deploy --root=/usr/local $HOST chromeos-base/tast-use-flags

When submitting changes to add new USE flags to the tast-use-flags package, please use Cq-Depend in your commit messages to ensure that changes land in the correct order.

If you‘re having trouble finding a way to specify your test’s dependencies, please ask for help on the tast-users mailing list.

Example changes

See the following changes for an example of adding a new containers software feature based on the containers USE flag and making a test depend on it:

(Note that the containers feature has since been renamed to oci.)


There are also autotest-capability:-prefixed features, which are added by the autocaps package as specified by YAML files in /usr/local/etc/autotest-capability. This exists in order to support porting existing Autotest-based video tests to Tast. Do not depend on capabilities from outside of video tests.

Hardware dependencies

Tast provides a way to run/skip tests based on the device characteristics.

Note that “device characteristics” here only consists of information that can be determined solely based on the DUT, without depending on the other surrounding environment, such as some config files on DUT.

The examples of the device characteristics are as follows:

  • Whether the device has a touch screen.
  • Whether the device has fingerprint.
  • Whether the device has an internal display.

For example, in order to run tests on DUT where touchscreen is available, the dependency can be declared in the HardwareDeps field of testing.Test.

func init() {
    HardwareDeps: hwdep.D(hwdep.Touchscreen()),

You can provide multiple Conditions to hwdep.D. In the case, the test will run only on DUTs where all the conditions are satisfied.

You can find the full list of supported conditions in the hwdep package.

Note that there are special kinds of hardware dependencies, named Model and SkipOnModel. With these dependencies, tests will be controlled based on the device type names, rather than the device characteristics. In general, it is recommended not to use these conditions. If you feel you need these conditions, it is recommended to reconsider whether there is an alternative (and more appropriate) condition. Examples of their expected use cases are:

  • There are known issues in a driver of a specific device, which cannot be fixed immediately. The test is stable on other models, and we would like to promoted it to critical.
  • There is a test running as informational. Flakiness failures are found only on a few models, but the test is stable on other models. With depending models, we can promote the test to critical on most of models, except ones where the test results flakiness. In this case, it is expected that a dedicated engineer is assigned to investigate the cause and its fix.

Adding new hardware conditions

In order to guarantee forward compatibility in ChromeOS infra, each Condition should be based on the chromiumos.config.api.HardwareFeatures protobuf schema.

For example, the hwdep.Touchscreen() can check whether Screen.TouchSupport is set to HardwareFeatures_PRESENT.

Note that currently a chromiumos.config.api.HardwareFeatures instance is generated internally by Tast at runtime, so only limited fields are filled. In the future, ChromeOS Infra test scheduler will be responsible for checking hardware dependencies before running Tast tests.

Here is an example end-to-end workflow: Let’s assume that a developer wants to add a new Tast test which requires a new hardware feature to be used in the test hardware constraints (e.g. “wifi chip vendor name is X”).

  1. The developer makes a change for that hardware feature.
  2. To test locally, run these commands to regenerate the go proto bindings.
    cros workon --host start cros-config-api
    sudo emerge cros-config-api
  3. The developer waits until the CL in #1 is landed, then implements some functions in the Tast framework supporting the new feature(s) using the new message type.
    • The Tast team reviews and approves such a change to Tast. Here is an example CL which puts some data into the protobuf in Tast.
  4. The developer writes test(s) with hwdeps in its test metadata using the above function in Tast.