Test Runner (Twister)

Twister scans for the set of test applications in the git repository and attempts to execute them. By default, it tries to build each test application on boards marked as default in the board definition file.

The default options will build the majority of the test applications on a defined set of boards and will run in an emulated environment if available for the architecture or configuration being tested.

Because of the limited test execution coverage, twister cannot guarantee local changes will succeed in the full build environment, but it does sufficient testing by building samples and tests for different boards and different configurations to help keep the complete code tree buildable.

When using (at least) one -v option, twister’s console output shows for every test application how the test is run (qemu, native_sim, etc.) or whether the binary was just built. The resultant status of a test is likewise reported in the twister.json and other report files. There are a few reasons why twister only builds a test and doesn’t run it:

• The test is marked as build_only: true in its .yaml configuration file.

• The test configuration has defined a harness but you don’t have it or haven’t set it up.

• The target device is not connected and not available for flashing

• You or some higher level automation invoked twister with --build-only.

To run Twister in the local tree, follow the steps below:

$ west twister

Note

The examples in this document invoke Twister as west twister, the west extension command, which works the same on all host operating systems. The following invocations are equivalent:

• west twister ... (recommended).

• ./scripts/twister ... (Linux/macOS) or python .\scripts\twister ... (Windows): invoking the script directly. This requires the Zephyr environment to be set up first (source zephyr-env.sh or zephyr-env.cmd).

All forms accept the same command line options.

If you want to run tests on one or more specific platforms, you can use the --platform option, it is a platform filter for testing, with this option, test suites will only be built/run on the platforms specified. This option also supports different revisions of one same board, you can use --platform board@revision to test on a specific revision.

The list of command line options supported by twister can be viewed with west twister --help. See Command Line Options for the full set of options.

The following pages cover additional Twister topics:

• Command Line Options
• Integration with pytest test framework
• Twister Status
• Twister blackbox tests

Board Configuration

To build tests for a specific board and to execute some of the tests on real hardware or in an emulation environment such as QEMU a board configuration file is required which is generic enough to be used for other tasks that require a board inventory with details about the board and its configuration that is only available during build time otherwise.

The board metadata file is located in the board directory and is structured using the YAML markup language. The example below shows a board with a data required for best test coverage for this specific board:

identifier: frdm_k64f
name: NXP FRDM-K64F
type: mcu
arch: arm
toolchain:
  - zephyr
  - gnuarmemb
supported:
  - arduino_gpio
  - arduino_i2c
  - netif:eth
  - adc
  - i2c
  - nvs
  - spi
  - gpio
  - usb_device
  - watchdog
  - can
  - pwm
testing:
  default: true

identifier:

A string that matches how the board is defined in the build system. This same string is used when building, for example when calling west build or cmake:

# with west
west build -b reel_board
# with cmake
cmake -DBOARD=reel_board ..

name:

The actual name of the board as it appears in marketing material.

vendor:

The board vendor. Used by the vendor_allow and vendor_exclude test scenario filters.

tier:

An optional integer indicating the board support tier. Used for reporting and to group platforms by their level of support.

type:

Type of the board or configuration. One of mcu, qemu, sim, unit or native.

simulation:

Simulator(s) used to simulate the platform, e.g. qemu.

simulation:
  - name: qemu
  - name: armfvp
    exec: FVP_Some_Platform
  - name: custom
    exec: AnotherBinary

By default, tests will be executed using the first entry in the simulation array. Another simulation can be selected with --simulation <simulation_name>. The exec attribute is optional. If it is set but the required simulator is not available, the tests will be built only. If it is not set and the required simulator is not available the tests will fail to run. The simulation name must match one of the elements of SUPPORTED_EMU_PLATFORMS.

arch:

Architecture of the board

toolchain:

The list of supported toolchains that can build this board. This should match one of the values used for ZEPHYR_TOOLCHAIN_VARIANT when building on the command line

ram:

Available RAM on the board (specified in KB). This is used to match test scenario requirements. If not specified we default to 128KB.

flash:

Available FLASH on the board (specified in KB). This is used to match test scenario requirements. If not specified we default to 512KB.

sysbuild: [True|False] (default False)

If true, applications for this platform are built using sysbuild by default.

twister: [True|False] (default True)

If false, Twister ignores this platform entirely and never builds or runs tests on it.

supported:

A list of features this board supports. This can be specified as a single word feature or as a variant of a feature class. For example:

supported:
  - pci

This indicates the board does support PCI. You can make a test scenario build or run only on such boards, or:

supported:
  - netif:eth
  - sensor:bmi16

A test scenario can depend on ‘eth’ to only test ethernet or on ‘netif’ to run on any board with a networking interface.

testing:

testing relating keywords to provide best coverage for the features of this board.

binaries:

A list of custom binaries to be kept for device testing.

default: [True|False]:

This is a default board, it will tested with the highest priority and is covered when invoking the simplified twister without any additional arguments.

ignore_tags:

Do not attempt to build (and therefore run) tests marked with this list of tags.

only_tags:

Only execute tests with this list of tags on a specific platform.

timeout_multiplier: <float> (default 1)

Multiply each test scenario timeout by specified ratio. This option allows to tune timeouts only for required platform. It can be useful in case naturally slow platform I.e.: HW board with power-efficient but slow CPU or simulation platform which can perform instruction accurate simulation but does it slowly.

flash_before: [True|False] (default False)

For pytest/shell harness hardware testing, flash the device before opening the serial port. This prevents serial port disconnection issues during flashing on some boards (e.g., those with USB CDC that reset during flash operations).

renode:

Configuration for the Renode simulator. Supports two keys: uart, the UART peripheral the harness connects to (e.g. sysbus.uart0), and resc, the Renode script (.resc) used to set up the simulated machine.

env:

A list of environment variables. Twister will check if all these environment variables are set, and otherwise skip this platform. This allows the user to define a platform which should be used, for example, only if some required software or hardware is present, and to signal that presence to twister using these environment variables.

variants:

A mapping of board variant (qualifier) names to per-variant overrides. Each entry is itself a platform definition and may override any of the keys above for that specific variant, while inheriting the remaining values from the top-level definition.

Tests

Tests are detected by the presence of a tests.yaml (sample.yaml and testcase.yaml support is deprecated) files in the application’s project directory. This test application configuration file may contain one or more entries in the tests: section each identifying a Test Scenario.

Twister and a Test application project.

Test application configurations are written using the YAML syntax and share the same structure as samples.

A Test Scenario is a set of conditions and variables defined in a Test Scenario entry, under which a set of Test Suites will be built and executed.

A Test Suite is a collection of Test Cases which are intended to be used to test a software program to ensure it meets certain requirements. The Test Cases in a Test Suite are either related or meant to be executed together.

Test Scenario, Test Suite, and Test Case names must follow to these basic rules:

1. The format of the Test Scenario identifier shall be a string without any spaces or special characters (allowed characters: alphanumeric and [_=]) consisting of multiple sections delimited with a dot (.).

2. Each Test Scenario identifier shall start with a section name followed by a subsection names delimited with a dot (.). For example, a test scenario that covers semaphores in the kernel shall start with kernel.semaphore.

3. All Test Scenario identifiers within a Test Configuration (testcase.yaml file) need to be unique. For example a testcase.yaml file covering semaphores in the kernel can have:

   • kernel.semaphore: For general semaphore tests

   • kernel.semaphore.stress: Stress testing semaphores in the kernel.

4. The full canonical name of a Test Suite is: <Test Application Project path>/<Test Scenario identifier>

5. Depending on the Test Suite implementation, its Test Case identifiers consist of at least three sections delimited with a dot (.):

   • Ztest tests: a Test Scenario identifier from the corresponding testcase.yaml file, a Ztest suite name, and a Ztest test name: <Test Scenario identifier>.<Ztest suite name>.<Ztest test name>

   • Standalone tests and samples: a Test Scenario identifier from the corresponding tests.yaml file where the last section signifies the standalone Test Case name, for example: debug.coredump.logging_backend.

The --no-detailed-test-id command line option modifies the above rules in this way:

1. A Test Suite name has only <Test Scenario identifier> component. Its Application Project path can be found in twister.json report as path: property.

2. With short Test Suite names in this mode, all corresponding Test Scenario names must be unique for the Twister execution scope.

The following is an example test configuration with a few options that are explained in this document.

tests:
  bluetooth.gatt:
    build_only: true
    platform_allow:
      - qemu_cortex_m3
      - qemu_x86
    tags:
      - bluetooth
  bluetooth.gatt.br:
    build_only: true
    extra_args:
      -CONF_FILE="prj_br.conf"
    filter: not CONFIG_DEBUG
    platform_exclude:
      -up_squared
    platform_allow:
      - qemu_cortex_m3 qemu_x86
    tags:
      bluetooth

A sample with tests will have the same structure with additional information related to the sample and what is being demonstrated:

sample:
  name: hello world
  description: Hello World sample, the simplest Zephyr application
tests:
  sample.basic.hello_world:
    build_only: true
    tags:
      - tests
    min_ram: 16
  sample.basic.hello_world.singlethread:
    build_only: true
    extra_args: CONF_FILE=prj_single.conf
    filter: not CONFIG_BT
    tags:
      - tests
    min_ram: 16

A Test Scenario entry in the tests: YAML dictionary has its Test Scenario identifier as a key.

Each Test Scenario entry in the Test Application configuration can define the following key/value pairs:

tags: <list of tags> (required)

A set of string tags for the test scenario. Usually pertains to functional domains but can be anything. Command line invocations of this script can filter the set of tests to run based on tag.

skip: <True|False> (default False)

skip test scenario unconditionally. This can be used for broken tests for example.

slow: <True|False> (default False)

Don’t run this test scenario unless --enable-slow or --enable-slow-only was passed in on the command line. Intended for time-consuming test scenarios that are only run under certain circumstances, like daily builds. These test scenarios are still compiled.

extra_args: <list of extra arguments>

Extra arguments to pass to build tool when building or running the test scenario.

Using namespacing, it is possible to apply extra_args only to some hardware. Currently architectures/platforms/simulation are supported:

common:
  tags: drivers adc
tests:
  test:
    depends_on: adc
  test_async:
    extra_args:
      - arch:x86:CONFIG_ADC_ASYNC=y
      - platform:qemu_x86:CONFIG_DEBUG=y
      - platform:mimxrt1060_evk:SHIELD=rk043fn66hs_ctg
      - simulation:qemu:CONFIG_MPU=y

extra_configs: <list of extra configurations>

Extra configuration options to be merged with a main prj.conf when building or running the test scenario. For example:

common:
  tags: drivers adc
tests:
  test:
    depends_on: adc
  test_async:
    extra_configs:
      - CONFIG_ADC_ASYNC=y

Using namespacing, it is possible to apply a configuration only to some hardware. Currently both architectures and platforms are supported:

common:
  tags: drivers adc
tests:
  test:
    depends_on: adc
  test_async:
    extra_configs:
      - arch:x86:CONFIG_ADC_ASYNC=y
      - platform:qemu_x86:CONFIG_DEBUG=y

extra_conf_files: <list of configuration files>

Extra Kconfig fragment files to merge into the build, as an alternative to passing CONF_FILE= through extra_args. Entries from common and the test scenario are concatenated. Prefer this field over extra_args for configuration files.

extra_overlay_confs: <list of overlay configuration files>

Extra Kconfig overlay fragments to merge into the build, as an alternative to passing OVERLAY_CONFIG= through extra_args. Entries from common and the test scenario are concatenated.

extra_dtc_overlay_files: <list of devicetree overlay files>

Extra devicetree overlay files to apply to the build, as an alternative to passing DTC_OVERLAY_FILE= through extra_args. Entries from common and the test scenario are concatenated.

build_only: <True|False> (default False)

If true, twister will not try to run the test even if the test is runnable on the platform.

This keyword is reserved for tests that are used to test if some code actually builds. A build_only test is not designed to be run in any environment and should not be testing any functionality, it only verifies that the code builds.

This option is often used to test drivers and the fact that they are correctly enabled in Zephyr and that the code builds, for example sensor drivers. Such test shall not be used to verify the functionality of the driver.

build_on_all: <True|False> (default False)

If true, attempt to build test scenario on all available platforms. This is mostly used in CI for increased coverage. Do not use this flag in new tests.

depends_on: <list of features>

A board or platform can announce what features it supports, this option will enable the test only those platforms that provide this feature.

levels: <list of levels>

Test levels this test should be part of. If a level is present, this test will be selectable using the command line option --level <level name>

min_ram: <integer>

estimated minimum amount of RAM in KB needed for this test to build and run. This is compared with information provided by the board metadata.

min_flash: <integer>

estimated minimum amount of ROM in KB needed for this test to build and run. This is compared with information provided by the board metadata.

timeout: <number of seconds>

Length of time to run test before automatically killing it. Default to 60 seconds.

arch_allow: <list of arches, such as x86, arm, arc>

Set of architectures that this test scenario should only be run for.

arch_exclude: <list of arches, such as x86, arm, arc>

Set of architectures that this test scenario should not run on.

toolchain_allow: <list of toolchain variants>

Set of toolchain variants that this test scenario should only be run for. The toolchain is the one configured for the run (see ZEPHYR_TOOLCHAIN_VARIANT). Platforms built with any other toolchain are filtered out.

toolchain_exclude: <list of toolchain variants>

Set of toolchain variants that this test scenario should not be run for.

vendor_allow: <list of vendors>

Set of platform vendors that this test scenario should only be run for. The vendor is defined as part of the board definition. Boards associated with this vendors will be included. Other boards, including those without a vendor will be excluded.

vendor_exclude: <list of vendors>

Set of platform vendors that this test scenario should not run on. The vendor is defined as part of the board. Boards associated with this vendors will be excluded.

platform_allow: <list of platforms>

Set of platforms that this test scenario should only be run for. Do not use this option to limit testing or building in CI due to time or resource constraints, this option should only be used if the test or sample can only be run on the allowed platform and nothing else.

integration_platforms: <YML list of platforms/boards>

This option limits the scope to the listed platforms when twister is invoked with the --integration option. Use this instead of platform_allow if the goal is to limit scope due to timing or resource constraints.

integration_toolchains: <YML list of toolchain variants>

This option expands the scope to all the listed toolchains variants and adds another vector of testing where desired. By default, test configurations are generated based on the toolchain configured in the environment:

test scenario -> platforms1 -> toolchain1 test scenario -> platforms2 -> toolchain1

When a platform supports multiple toolchains that are available during the twister run, it is possible to expand the test configurations to include additional tests for each toolchain. For example, if a platform supports toolchains toolchain1 and toolchain2, and the test scenario includes:

integration_toolchains:
  - toolchain1
  - toolchain2

the following configurations are generated:

test scenario -> platforms1 -> toolchain1 test scenario -> platforms1 -> toolchain2 test scenario -> platforms2 -> toolchain1 test scenario -> platforms2 -> toolchain2

Note

This functionality is evaluated always and is not limited to the --integration option.

platform_exclude: <list of platforms>

Set of platforms that this test scenario should not run on.

platform_type: <list of platform types>

Restrict this test scenario to platforms of the given type(s). A platform’s type is declared via the type: key in its board metadata. Supported values are mcu, qemu, sim, unit and native. Platforms whose type is not in this list are filtered out.

simulation_exclude: <list of simulators>

Set of simulators that this test scenario should not run on. Supported values are qemu, simics, xt-sim, renode, nsim, mdb-nsim, tsim, armfvp, native and custom.

extra_sections: <list of extra binary sections>

When computing sizes, twister will report errors if it finds extra, unexpected sections in the Zephyr binary unless they are named here. They will not be included in the size calculation.

sysbuild: <True|False> (default False)

Build the project using sysbuild infrastructure. Only the main project’s generated devicetree and Kconfig will be used for filtering tests. on device testing must use the hardware map, or west flash to load the images onto the target. The --erase option of west flash is not supported with this option. Usage of unsupported options will result in tests requiring sysbuild support being skipped.

harness: <string>

A harness keyword in the testcase.yaml file identifies a Twister harness needed to run a test successfully. A harness is a feature of Twister and implemented by Twister, some harnesses are defined as placeholders and have no implementation yet.

A harness can be seen as the handler that needs to be implemented in Twister to be able to evaluate if a test passes criteria. For example, a keyboard harness is set on tests that require keyboard interaction to reach verdict on whether a test has passed or failed, however, Twister lack this harness implementation at the moment.

Supported harnesses:

• ztest

• test

• console

• pytest

• gtest

• robot

• ctest

• shell

• power

• display_capture

• script

• bsim

See Harnesses for more information.

platform_key: <list of platform attributes>

Often a test needs to only be built and run once to qualify as passing. Imagine a library of code that depends on the platform architecture where passing the test on a single platform for each arch is enough to qualify the tests and code as passing. The platform_key attribute enables doing just that.

For example to key on (arch, simulation) to ensure a test is run once per arch and simulation (as would be most common):

platform_key:
  - arch
  - simulation

Adding platform (board) attributes to include things such as soc name, soc family, and perhaps sets of IP blocks implementing each peripheral interface would enable other interesting uses. For example, this could enable building and running SPI tests once for each unique IP block.

harness_config: <harness configuration options>

Extra harness configuration options to be used to select a board and/or for handling generic Console with regex matching. Config can announce what features it supports. This option will enable the test to run on only those platforms that fulfill this external dependency.

fixture: <string or list>

Specify a test scenario dependency on an external device(e.g., sensor), and identify setups that fulfill this dependency. It depends on specific test setup and board selection logic to pick the particular board(s) out of multiple boards that fulfill the dependency in an automation setup based on fixture keyword. Some sample fixture names are i2c_hts221, i2c_bme280, i2c_FRAM, ble_fw and gpio_loop.

ztest_suite_repeat: <int> (default 1)

This parameter specifies the number of times the entire test suite should be repeated.

ztest_test_repeat: <int> (default 1)

This parameter specifies the number of times each individual test within the test suite should be repeated.

ztest_test_shuffle: <True|False> (default False)

This parameter indicates whether the order of the tests within the test suite should be shuffled. When set to true, the tests will be executed in a random order.

The following is an example yaml file with robot harness_config options.

tests:
  robot.example:
    harness: robot
    harness_config:
      robot_testsuite: [robot file path]

It can be more than one test suite using a list.

tests:
  robot.example:
    harness: robot
    harness_config:
      robot_testsuite:
        - [robot file path 1]
        - [robot file path 2]
        - [robot file path n]

One or more options can be passed to robotframework.

tests:
  robot.example:
    harness: robot
    harness_config:
      robot_testsuite: [robot file path]
      robot_option:
        - --exclude tag
        - --stop-on-error

filter: <expression>

Filter whether the test scenario should be run by evaluating an expression against an environment containing the following values:

{ ARCH : <architecture>,
  PLATFORM : <platform>,
  <all CONFIG_* key/value pairs in the test's generated defconfig>,
  *<env>: any environment variable available
}

Twister will first evaluate the expression to find if a “limited” cmake call, i.e. using package_helper cmake script, can be done.

Existence of “dt_*” entries indicates devicetree is needed. Refer to Devicetree Filtering Expressions for detailed description of the different DT expressions available.

Existence of “CONFIG*” entries indicates kconfig is needed. If there are no other types of entries in the expression a filtration can be done without creating a complete build system. If there are entries of other types a full cmake is required.

The grammar for the expression language is as follows:

expression : expression 'and' expression
           | expression 'or' expression
           | 'not' expression
           | '(' expression ')'
           | symbol '==' constant
           | symbol '!=' constant
           | symbol '<' NUMBER
           | symbol '>' NUMBER
           | symbol '>=' NUMBER
           | symbol '<=' NUMBER
           | symbol 'in' list
           | symbol ':' STRING
           | symbol
           ;

list : '[' list_contents ']';

list_contents : constant (',' constant)*;

constant : NUMBER | STRING;

For the case where expression ::= symbol, it evaluates to true if the symbol is defined to a non-empty string.

Operator precedence, starting from lowest to highest:

• or (left associative)

• and (left associative)

• not (right associative)

• all comparison operators (non-associative)

arch_allow, arch_exclude, platform_allow, platform_exclude are all syntactic sugar for these expressions. For instance:

arch_exclude = x86 arc

Is the same as:

filter = not ARCH in ["x86", "arc"]

The : operator compiles the string argument as a regular expression, and then returns a true value only if the symbol’s value in the environment matches. For example, if CONFIG_SOC="stm32f107xc" then

filter = CONFIG_SOC : "stm.*"

Would match it.

required_snippets: <list of needed snippets>

Snippets are supported in twister for test scenarios that require them. As with normal applications, twister supports using the base zephyr snippet directory and test application directory for finding snippets. Listed snippets will filter supported tests for boards (snippets must be compatible with a board for the test to run on them, they are not optional).

The following is an example yaml file with 2 required snippets.

tests:
  snippet.example:
    required_snippets:
      - cdc-acm-console
      - user-snippet-example

required_applications: <list of required applications> (default empty)

Specify a list of test applications that must be built before current test can run. It enables sharing of built applications between test scenarios, allowing tests to access build artifacts from other applications.

Each required application entry supports:

• application: Test scenario identifier (required)

• name: Deprecated alias for application (still accepted for backward compatibility, but application should be used in new configurations)

• platform: Target platform (optional, defaults to current test’s platform)

• path: Directory path where Twister should search for the application (optional). Can be an absolute path or a path relative to the directory containing the test’s YAML file. Environment variables are expanded. If not specified, Twister searches in the same directory as the referring test’s YAML file.

Required applications are automatically discovered and built by Twister. If a required application is not already loaded, Twister searches for it in the directory specified by path or, if path is not set, in the same directory as the referring test’s YAML file. When reusing build directories (e.g., with --no-clean), Twister can find required applications in the current build directory.

How it works:

• Twister builds the required applications first

• The main test application waits for required applications to complete

• Build directories of required applications are made available to the test harness

• For pytest harness, build directories are passed via --required-build arguments and accessible through the required_build_dirs fixture

When combined with build: false, the current test scenario skips its own build step entirely and uses the first required application’s build artifacts as its image. This is useful for scenarios that serve purely as test harnesses for an image built elsewhere.

Example configuration:

tests:
  # Requires two applications, second one from a different path and with a fixed platform
  sample.required_app_demo:
    harness: pytest
    required_applications:
      - application: sample.shared_app
      - application: other.app
        path: ../other_app
        platform: native_sim
  # No self build, use the first required application as the test image
  sample.no_self_build:
    build: false
    harness: pytest
    required_applications:
      - application: sample.basic.helloworld
        path: $ZEPHYR_BASE/samples/hello_world
  sample.shared_app:
    build_only: true

Limitations:

• Not supported with --runtime-artifact-cleanup, as build artifacts of required applications must be retained for use by the main test application.

• Not supported with --subset: a required application and the test depending on it may be assigned to different subsets, making build artifacts unavailable at test execution time.

build: <True|False> (default True)

If false, the test scenario skips its own build step and uses the build artifacts from the first entry in required_applications as its image. This is useful for scenarios that serve purely as a test harness for an image built by another scenario.

Constraints:

• required_applications must be non-empty.

• Supported harnesses: pytest-based (e.g. pytest, shell) and bsim.

• QEMU platforms are not supported.

expect_reboot: <True|False> (default False)

Notify twister that the test scenario is expected to reboot while executing. When enabled, twister will suppress warnings about unexpected multiple runs of a testsuite or testcase.

modules: <list of module names>

Build and run this test scenario only when all of the listed modules are present in the workspace. Scenarios that require a module which is not available are filtered out.

type: <string> (default integration)

Test type of the scenario. Set to unit for unit tests that are built for the unit_testing board and run on the host without the full Zephyr build system.

testcases: <list of test case names>

Explicitly declare the list of test case names that make up this scenario. This is normally detected automatically (for example from the ztest source) and only needs to be set for harnesses that cannot be introspected.

ignore_faults: <True|False> (default False)

Do not mark the test scenario as failed if a fault is detected in the output while the test is running.

ignore_qemu_crash: <True|False> (default False)

Do not mark the test scenario as failed if QEMU crashes while the test is running.

The set of test scenarios that actually run depends on directives in the test scenario file and options passed in on the command line. If there is any confusion, running with -v or examining the test plan (testplan.json) can help show why particular test scenarios were filtered out.

To load arguments from a file, add + before the file name, e.g., +file_name. File content must be one or more valid arguments separated by line break instead of white spaces.

Most everyday users will run with no arguments.

Managing tests timeouts

There are several parameters which control tests timeouts on various levels:

• timeout option in each test scenario. See here for more details.

• timeout_multiplier option in board configuration. See here for more details.

• --timeout-multiplier twister option which can be used to adjust timeouts in exact twister run. It can be useful in case of simulation platform as simulation time may depend on the host speed & load or we may select different simulation method (i.e. cycle accurate but slower one), etc…

Overall test scenario timeout is a multiplication of these three parameters.

Devicetree Filtering Expressions

Expressions starting with “dt_*” are used to filter boards based on specific devicetree properties, such as compatibles, aliases, node labels, node properties, chosen nodes, etc. when selecting test scenarios.

Note

The source code for these expressions can be found at scripts/pylib/twister/expr_parser.py.

Expressions

dt_compat_enabled(compat)

Purpose:

Checks if any DT node with the specified compatible string (compat) is enabled.

Parameters:

• compat: The compatible string to match.

dt_alias_exists(alias)

Purpose:

Checks if any DT node with the specified alias exists and is enabled.

Parameters:

• alias: The alias (defined in aliases node) to match.

dt_enabled_alias_with_parent_compat(alias, compat)

Purpose:

Checks if the DT has an enabled alias node whose parent has the specified compatible string. Useful for nodes like gpio-leds child nodes, which may not have their own compatible.

Parameters:

• alias: The alias (defined in aliases node) to match.

• compat: The parent node’s compatible string to match.

dt_label_with_parent_compat_enabled(label, compat)

Purpose:

Checks if a DT node with the specified label exists, is enabled, and its parent has the specified compatible string.

Parameters:

• label: The node label to match.

• compat: The parent node’s compatible string to match.

dt_label_compat_enabled(label, compat)

Purpose:

Checks if a DT node with the specified label exists, is enabled, and has the specified compatible string.

Parameters:

• label: The node label to match.

• compat: The node compatible string to match.

dt_chosen_enabled(chosen)

Purpose:

Checks if a DT chosen property with the specified name exists and the node assigned to it is enabled.

Parameters:

• chosen: The name of the chosen property.

dt_nodelabel_enabled(label)

Purpose:

Checks if a DT node with the specified label exists and is enabled.

Parameters:

• label: The node label to match.

dt_nodelabel_prop_enabled(label, prop)

Purpose:

Checks if a DT node with the specified label exists, is enabled, and has the specified property with a non-empty value.

Parameters:

• label: The node label to match.

• prop: The node’s property to check.

dt_node_has_prop(node_id, prop)

Purpose:

Checks if a DT node (specified by alias or path) has the specified property, regardless of its status. Useful for nodes that do not have a status, like zephyr,user node.

Parameters:

• node_id: The node alias (defined in aliases node) or node path to match.

• prop: The node’s property to check.

Usage

These expressions are used in Twister’s test scenarios filtering logic to select boards that match specific DT conditions. For example:

tests:
  - test: my_test
    filter: dt_compat_enabled("my-compat-string")

The test scenario my_test will only build for boards where a DT node with my-compat-string is enabled.

Harnesses

A harness is the mechanism Twister uses to run a test and decide whether it passed or failed. After a test image is built and started on its target (real hardware, an emulator, or the host), the harness drives the interaction with the running image – providing input, capturing output, or handing execution over to an external test runner – and interprets the result to assign a status to each test case.

A test scenario selects a harness with the harness: entry in its tests.yaml and tunes its behavior through harness_config. When no harness is specified, the default test harness is used. Different harnesses serve different needs: some parse the device’s console output against expected patterns, while others delegate execution to an external framework such as pytest, Robot Framework, or ctest. The pages linked below describe each supported harness and its harness_config options.

Harnesses ztest, gtest and console are based on parsing of the output and matching certain phrases. ztest and gtest harnesses look for pass/fail/etc. frames defined in those frameworks.

Some widely used harnesses that are not supported yet:

• keyboard

• net

• bluetooth

The following is an example yaml file with a few harness_config options.

sample:
  name: HTS221 Temperature and Humidity Monitor
common:
  tags: sensor
  harness: console
  harness_config:
    type: multi_line
    ordered: false
    regex:
      - "Temperature:(.*)C"
      - "Relative Humidity:(.*)%"
    fixture: i2c_hts221
tests:
  test:
    tags: sensors
    depends_on: i2c

• Ctest
• Gtest
• Pytest
• Console
• Robot
• Power
• Display capture
• Script
• Bsim
• Shell

Selecting platform scope

One of the key features of Twister is its ability to decide on which platforms a given test scenario should run. This behavior has its roots in Twister being developed as a test runner for Zephyr’s CI. With hundreds of available platforms and thousands of tests, the testing tools should be able to adapt the scope and select/filter out what is relevant and what is not.

Twister always prepares an initial list of platforms in scope for a given test, based on command line arguments and the test’s configuration. Then, platforms that don’t fulfill the conditions required in the configuration yaml (e.g. minimum ram) are filtered out from the scope. Using --force-platform allows to override filtering caused by platform_allow, platform_exclude, arch_allow and arch_exclude keys in test configuration files.

Command line arguments define the initial scope in the following way:

• -p/--platform <platform_name> (can be used multiple times): only platforms passed with this argument;

• -l/--all: all available platforms;

• -G/--integration: all platforms from an integration_platforms list in a given test configuration file. If a test has no integration_platforms “scope presumption” will happen;

• No scope argument: “scope presumption” will happen.

“Scope presumption”: A list of Twister’s default platforms is used as the initial list. If nothing is left after the filtration, the platform_allow list is used as the initial scope.

Running in Integration Mode

This mode is used in continuous integration (CI) and other automated environments used to give developers fast feedback on changes. The mode can be activated using the --integration option of twister and narrows down the scope of builds and tests if applicable to platforms defined under the integration keyword in the test configuration file (tests.yaml).

Running tests on custom emulator

Apart from the already supported QEMU and other simulated environments, Twister supports running any out-of-tree custom emulator defined in the board’s board.cmake. To use this type of simulation, add the following properties to custom_board/custom_board.yaml:

simulation:
  - name: custom
    exec: <name_of_emu_binary>

This tells Twister that the board is using a custom emulator called <name_of_emu_binary>, make sure this binary exists in the PATH.

Then, in custom_board/board.cmake, set the supported emulation platforms to custom:

set(SUPPORTED_EMU_PLATFORMS custom)

Finally, implement the run_custom target in custom_board/board.cmake. It should look something like this:

add_custom_target(run_custom
  COMMAND
  <name_of_emu_binary to invoke during 'run'>
  <any args to be passed to the command, i.e. ${BOARD}, ${APPLICATION_BINARY_DIR}/zephyr/zephyr.elf>
  WORKING_DIRECTORY ${APPLICATION_BINARY_DIR}
  DEPENDS ${logical_target_for_zephyr_elf}
  USES_TERMINAL
  )

Running Tests in Random Order

Enable ZTEST framework’s CONFIG_ZTEST_SHUFFLE config option to run your tests in random order. This can be beneficial for identifying dependencies between test cases. For native_sim platforms, you can provide the seed to the random number generator by providing --seed=value as an argument to twister. See Shuffling Test Sequence for more details.

Running Tests on Hardware

Beside being able to run tests in QEMU and other simulated environments, twister supports running most of the tests on real devices and produces reports for each run with detailed FAIL/PASS results.

Executing tests on a single device

To use this feature on a single connected device, run twister with the following new options:

LinuxWindows

west twister --device-testing --device-serial /dev/ttyACM0 \
--device-serial-baud 115200 -p frdm_k64f  -T tests/kernel

The --device-serial option denotes the serial device the board is connected to. This needs to be accessible by the user running twister. You can run this on only one board at a time, specified using the --platform option. If the platform supports multiple serial ports, you can provide --device-serial multiple times, and it will be passed to the pytest harness. Alternatively you can use the hardware map, see multi-core testing for more details

The --device-serial-baud option is only needed if your device does not run at 115200 baud.

To support devices without a physical serial port, use the --device-serial-pty option. In this cases, log messages are captured for example using a script. In this case you can run twister with the following options:

LinuxWindows

west twister --device-testing --device-serial-pty "script.py" \
-p intel_adsp/cavs25 -T tests/kernel

The script is user-defined and handles delivering the messages which can be used by twister to determine the test execution status.

The --device-flash-timeout option allows to set explicit timeout on the device flash operation, for example when device flashing takes significantly large time.

The --device-flash-with-test option indicates that on the platform the flash operation also executes a test scenario, so the flash timeout is increased by a test scenario timeout.

Executing tests on multiple devices

To build and execute tests on multiple devices connected to the host PC, a hardware map needs to be created with all connected devices and their details such as the serial device, baud and their IDs if available. Run the following command to produce the hardware map:

$ west twister --generate-hardware-map map.yml

The generated hardware map file (map.yml) will have the list of connected devices, for example:

LinuxWindows

- connected: true
  id: OSHW000032254e4500128002ab98002784d1000097969900
  platform: unknown
  product: DAPLink CMSIS-DAP
  runner: pyocd
  serial: /dev/cu.usbmodem146114202
- connected: true
  id: 000683759358
  platform: unknown
  product: J-Link
  runner: unknown
  serial: /dev/cu.usbmodem0006837593581

Any options marked as unknown need to be changed and set with the correct values, in the above example the platform names, the products and the runners need to be replaced with the correct values corresponding to the connected hardware. In this example we are using a reel_board and an nrf52840dk/nrf52840:

LinuxWindows

- connected: true
  id: OSHW000032254e4500128002ab98002784d1000097969900
  platform: reel_board
  product: DAPLink CMSIS-DAP
  runner: pyocd
  serial: /dev/cu.usbmodem146114202
  baud: 9600
- connected: true
  id: 000683759358
  platform: nrf52840dk/nrf52840
  product: J-Link
  runner: nrfjprog
  serial: /dev/cu.usbmodem0006837593581
  baud: 9600

The baud entry is only needed if not running at 115200.

If the map file already exists, then new entries are added and existing entries will be updated. This way you can use one single master hardware map and update it for every run to get the correct serial devices and status of the devices.

With the hardware map ready, you can run any tests by pointing to the map

LinuxWindows

west twister --device-testing --hardware-map map.yml -T samples/hello_world/

The above command will result in twister building tests for the platforms defined in the hardware map and subsequently flashing and running the tests on those platforms.

Note

Currently only boards with support for pyocd, nrfjprog, jlink, openocd, or dediprog are supported with the hardware map features. Boards that require other runners to flash the Zephyr binary are still work in progress.

Hardware map allows to set --device-flash-timeout and --device-flash-with-test command line options as flash-timeout and flash-with-test fields respectively. These hardware map values override command line options for the particular platform.

Serial PTY support using --device-serial-pty can also be used in the hardware map:

- connected: true
  id: None
  platform: intel_adsp/cavs25
  product: None
  runner: intel_adsp
  serial_pty: path/to/script.py
  runner_params:
    - --remote-host=remote_host_ip_addr
    - --key=/path/to/key.pem

The runner_params field indicates the parameters you want to pass to the west runner. For some boards the west runner needs some extra parameters to work. It is equivalent to following west and twister commands.

LinuxWindows

west flash --remote-host remote_host_ip_addr --key /path/to/key.pem

west twister -p intel_adsp/cavs25 --device-testing --device-serial-pty script.py
--west-flash="--remote-host=remote_host_ip_addr,--key=/path/to/key.pem"

Note

For serial PTY, the “–generate-hardware-map” option cannot scan it out and generate a correct hardware map automatically. You have to edit it manually according to above example. This is because the serial port of the PTY is not fixed and being allocated in the system at runtime.

If west is not available or does not know how to flash your system, a custom flash command can be specified using the flash-command flag. The script is called with a --build-dir with the path of the current build, as well as a --board-id flag to identify the specific device when multiple are available in a hardware map.

LinuxWindows

west twister -p npcx9m6f_evb --device-testing --device-serial /dev/ttyACM0
--flash-command './custom_flash_script.py,--flag,"complex, argument"'

Would result in calling ./custom_flash_script.py --build-dir <build directory> --board-id <board identification> --flag "complex, argument".

Fixtures

Some tests require additional setup or special wiring specific to the test. Running the tests without this setup or test fixture may fail. A test scenario can specify the fixture it needs which can then be matched with hardware capability of a board and the fixtures it supports via the command line or using the hardware map file.

Fixtures are defined in the hardware map file as a list:

- connected: true
  fixtures:
    - gpio_loopback
  id: 0240000026334e450015400f5e0e000b4eb1000097969900
  platform: frdm_k64f
  product: DAPLink CMSIS-DAP
  runner: pyocd
  serial: /dev/ttyACM9

When running twister with --device-testing, the configured fixture in the hardware map file will be matched to test scenarios requesting the same fixtures and these tests will be executed on the boards that provide this fixture.

Fixtures can also be provided via twister command option --fixture, this option can be used multiple times and all given fixtures will be appended as a list. And the given fixtures will be assigned to all boards, this means that all boards set by current twister command can run those test scenarios which request the same fixtures.

Some fixtures allow for configuration strings to be appended, separated from the fixture name by a :. Only the fixture name is matched against the fixtures requested by test scenarios.

Notes

It may be useful to annotate board descriptions in the hardware map file with additional information. Use the notes keyword to do this. For example:

- connected: false
  fixtures:
    - gpio_loopback
  id: 000683290670
  notes: An nrf5340dk/nrf5340 is detected as an nrf52840dk/nrf52840 with no serial
    port, and three serial ports with an unknown platform.  The board id of the serial
    ports is not the same as the board id of the development kit.  If you regenerate
    this file you will need to update serial to reference the third port, and platform
    to nrf5340dk/nrf5340/cpuapp or another supported board target.
  platform: nrf52840dk/nrf52840
  product: J-Link
  runner: jlink
  serial: null

Overriding Board Identifier

When (re-)generated the hardware map file will contain an id keyword that serves as the argument to --board-id when flashing. In some cases the detected ID is not the correct one to use, for example when using an external J-Link probe. The probe_id keyword overrides the id keyword for this purpose. For example:

- connected: false
  id: 0229000005d9ebc600000000000000000000000097969905
  platform: mimxrt1060_evk
  probe_id: 000609301751
  product: DAPLink CMSIS-DAP
  runner: jlink
  serial: null

Using Single Board For Multiple Variants

The platform attribute can be a list of names or a string with names separated by spaces. This allows to run tests for different platform variants on the same physical board, without re-configuring the hardware map file for each variant. For example:

- connected: true
  id: '001234567890'
  platform:
  - nrf5340dk/nrf5340/cpuapp
  - nrf5340dk/nrf5340/cpuapp/ns
  product: J-Link
  runner: nrfjprog
  serial: /dev/ttyACM1

Multi-Core testing support

Twister supports testing multi-core applications where different cores use separate UART interfaces. This feature works only with the pytest harness (harness: pytest). Generated hardware map should contain multiple entries for the same physical device, each representing a different core connection. For example:

- connected: true
  id: 001234567890
  serial: /dev/ttyACM0
- connected: true
  id: 001234567890
  platform:
  - nrf54l15dk/nrf54l15/cpuapp
  product: J-Link
  runner: nrfutil
  serial: /dev/ttyACM1

Both instances share the same device ID but have different serial ports, allowing tests to interact with multiple cores simultaneously. Each connection is handled independently with separate log files.

Multi-DUTs testing support

Twister supports test scenarios that require more than one device. This feature works only with the pytest harness (harness: pytest). Hardware and native_sim execution environments are supported.

To declare that a test needs an additional device, add required_devices under harness_config in the test’s YAML file. Each entry in the list describes one extra DUT. An empty entry {} reserves a second device with the same platform and application as the main DUT. See required_devices for all available options.

Example test configuration:

tests:
  multidut.basic:
    harness: pytest
    harness_config:
      required_devices:
        - {}

The hardware map must contain at least one entry per required device. Each entry needs a matching platform and a serial connection:

- connected: true
  id: 01
  platform: nrf52840dk/nrf52840
  serial: /dev/ttyACM0
- connected: true
  id: 02
  platform: nrf52840dk/nrf52840
  serial: /dev/ttyACM1

Run the test on hardware with:

$ west twister -vv -ll debug -T tests/subsys/testsuite/multidut \
  --device-testing --hardware-map map.yaml

Run the test on native_sim (no hardware map required):

$ west twister -vv -ll debug -T tests/subsys/testsuite/multidut -p native_sim

Twister reserves all required devices (or creates placeholder entries if native_sim is used), then passes them to pytest with all necessary information (platform, serial connection, build artifacts to flash, etc.) so the test can interact with all devices.

An example multi-DUT test can be found at tests/subsys/testsuite/multidut.

Quarantine

Twister allows user to provide configuration files defining a list of tests or platforms to be put under quarantine. Such tests will be skipped and marked accordingly in the output reports. This feature is especially useful when running larger test suits, where a failure of one test can affect the execution of other tests (e.g. putting the physical board in a corrupted state).

To use the quarantine feature one has to add the argument --quarantine-list <PATH_TO_QUARANTINE_YAML> to a twister call. Multiple quarantine files can be used. The current status of tests on the quarantine list can also be verified by adding --quarantine-verify to the above argument. This will make twister skip all tests which are not on the given list.

A quarantine yaml is a sequence of dictionaries. Each dictionary must have at least one of the following keys: scenarios, platforms, architectures or simulations. A combination of these entries is allowed. An optional comment entry can be used to provide more details (e.g., a link to a reported issue). These comments will also be added to the output reports.

When quarantining a class of tests or many scenarios in a single testsuite or when dealing with multiple issues within a subsystem, it is possible to use regular expressions, for example, kernel.* would quarantine all kernel tests.

An example of entries in a quarantine yaml:

- scenarios:
    - sample.basic.helloworld
  comment: "Link to the issue: https://github.com/zephyrproject-rtos/zephyr/pull/33287"

- scenarios:
    - kernel.common
    - kernel.common.(misra|tls)
    - kernel.common.nano64
  platforms:
    - .*_cortex_.*
    - native_sim

- platforms:
    - qemu_x86
  comment: "filter out qemu_x86"

- architectures:
    - riscv

- simulations:
    - armfvp

Test Output and Reports

By default, Twister writes all of its output to a twister-out directory created in the current working directory. Use -O/--outdir to choose a different location. On each run this directory is cleaned, unless --no-clean is given; --clobber-output controls what cleaning does.

Top-level reports

The following files are written at the root of the output directory:

twister.json

The primary machine-readable report. It contains an entry for every selected test suite and test case with its status, target platform, execution time, memory footprint, any recorded data, and the environment and options used for the run.

testplan.json

The resolved test plan: every test instance (test scenario times platform) that Twister considered, including those that were filtered out together with the reason. This is the file to inspect to understand why a given scenario did or did not run. It can be reused with --load-tests to replay the same selection.

twister.xml

JUnit XML summary suitable for CI systems.

twister_report.xml

JUnit XML report including all test cases (not just the summary).

twister_suite_report.xml

JUnit XML report grouped by test suite.

twister.log

Human-readable log of the whole run.

twister_footprint.json

ROM/RAM footprint report. Only generated when --footprint-report is used.

The report base name (twister) can be changed with --report-name, and --report-suffix appends a suffix (for example a version or commit ID) to all generated file names. Use -o/--report-dir to write the reports to a directory other than the output directory, and --platform-reports to additionally emit a per-platform <platform>.json and <platform>.xml. --report-summary prints a summary of the failures from the latest run without rebuilding.

Per-test artifacts

Each test instance has its own build directory under the output directory, named after the platform and the test: twister-out/<platform>/<test path>/<scenario>/. In addition to the normal Zephyr build artifacts (for example zephyr/zephyr.elf), it may contain:

build.log

Output of the build for this instance.

handler.log

Console output captured from the device or emulator while running the test.

twister_harness.log

Log produced by pytest-based harnesses (for example pytest and shell).

recording.csv

Data fields captured by the record option of the console harness, when configured.

Twister Configuration File

The Twister configuration file (test_config.yaml, passed with --test-config) can be used to customize various aspects of twister and the default enabled options and features. This allows tweaking the filtering capabilities depending on the environment and makes it possible to adapt and improve coverage when targeting different sets of platforms.

Note

This file (selected with --test-config) configures a whole Twister run. It is distinct from the per-application test configuration in tests.yaml, which describes individual test scenarios.

The Twister configuration file also adds support for test levels and the ability to assign a specific test to one or more levels. Using command line options of twister it is then possible to select a level and just execute the tests included in this level.

Additionally, the configuration file allows defining level dependencies and additional inclusion of tests into a specific level if the test itself does not have this information already.

In the configuration file you can include complete components using regular expressions and you can specify which test level to import from the same file, making management of levels easier.

To help with testing outside of upstream CI infrastructure, additional options are available in the configuration file, which can be hosted locally. As of now, those options are available:

• Ability to ignore default platforms as defined in board definitions (Those are mostly emulation platforms used to run tests in upstream CI)

• Option to specify your own list of default platforms overriding what upstream defines.

• Ability to override build_on_all options used in some test scenarios. This will treat tests or sample as any other just build for default platforms you specify in the configuration file or on the command line.

• Ignore some logic in twister to expand platform coverage in cases where default platforms are not in scope.

Platform Configuration

The following options control platform filtering in twister:

• override_default_platforms: override default key a platform sets in board configuration and instead use the list of platforms provided in the configuration file as the list of default platforms. This option is set to False by default.

• increased_platform_scope: This option is set to True by default, when disabled, twister will not increase platform coverage automatically and will only build and run tests on the specified platforms.

• default_platforms: A list of additional default platforms to add. This list can either be used to replace the existing default platforms or can extend it depending on the value of override_default_platforms.

And example platforms configuration:

platforms:
  override_default_platforms: true
  increased_platform_scope: false
  default_platforms:
    - qemu_x86

Test Level Configuration

The test configuration allows defining test levels, level dependencies and additional inclusion of tests into a specific test level if the test itself does not have this information already.

In the configuration file you can include complete components using regular expressions and you can specify which test level to import from the same file, making management of levels simple.

And example test level configuration:

levels:
  - name: my-test-level
    description: >
      my custom test level
    adds:
      - kernel.threads.*
      - kernel.timer.behavior
      - arch.interrupt
      - boards.*

Combined configuration

To mix the Platform and level configuration, you can take an example as below:

An example platforms plus level configuration:

platforms:
  override_default_platforms: true
  default_platforms:
    - frdm_k64f
levels:
  - name: smoke
    description: >
        A plan to be used verifying basic zephyr features.
  - name: unit
    description: >
        A plan to be used verifying unit test.
  - name: integration
    description: >
        A plan to be used verifying integration.
  - name: acceptance
    description: >
        A plan to be used verifying acceptance.
  - name: system
    description: >
        A plan to be used verifying system.
  - name: regression
    description: >
        A plan to be used verifying regression.

To run with above test_config.yaml file, only default_platforms with given test level test scenarios will run.

$ west twister --test-config=<path to>/test_config.yaml -T tests --level="smoke"