| .. _twister_script: |
| |
| Test Runner (Twister) |
| ##################### |
| |
| This script scans for the set of unit test applications in the git repository |
| and attempts to execute them. By default, it tries to build each test |
| case on boards marked as default in the board definition file. |
| |
| The default options will build the majority of the tests on a defined set of |
| boards and will run in an emulated environment if available for the |
| architecture or configuration being tested. |
| |
| In normal use, twister runs a limited set of kernel tests (inside |
| an emulator). Because of its 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 how the test is run (qemu, native_posix, etc.) or |
| whether the binary was just built. 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``. |
| |
| These also affect the outputs of ``--testcase-report`` and |
| ``--detailed-report``, see their respective ``--help`` sections. |
| |
| To run the script in the local tree, follow the steps below: |
| |
| :: |
| |
| $ source zephyr-env.sh |
| $ ./scripts/twister |
| |
| If you have a system with a large number of cores and plenty of free storage space, |
| you can build and run all possible tests using the following options: |
| |
| :: |
| |
| $ ./scripts/twister --all --enable-slow |
| |
| This will build for all available boards and run all applicable tests in |
| a simulated (for example QEMU) environment. |
| |
| The list of command line options supported by twister can be viewed using:: |
| |
| $ ./scripts/twister --help |
| |
| |
| |
| 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: |
| |
| .. code-block:: yaml |
| |
| identifier: frdm_k64f |
| name: NXP FRDM-K64F |
| type: mcu |
| arch: arm |
| toolchain: |
| - zephyr |
| - gnuarmemb |
| - xtools |
| 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. |
| type: |
| Type of the board or configuration, currently we support 2 types: mcu, qemu |
| 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 testcase |
| requirements. If not specified we default to 128KB. |
| flash: |
| Available FLASH on the board (specified in KB). This is used to match testcase |
| requirements. If not specified we default to 512KB. |
| 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 testcase build or |
| run only on such boards, or: |
| |
| :: |
| |
| supported: |
| - netif:eth |
| - sensor:bmi16 |
| |
| A testcase can both 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. |
| |
| 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. |
| |
| Test Cases |
| ********** |
| |
| Test cases are detected by the presence of a 'testcase.yaml' or a 'sample.yaml' |
| files in the application's project directory. This file may contain one or more |
| entries in the test section each identifying a test scenario. |
| |
| The name of each testcase needs to be unique in the context of the overall |
| testsuite and has to follow basic rules: |
| |
| #. The format of the test identifier shall be a string without any spaces or |
| special characters (allowed characters: alphanumeric and [\_=]) consisting |
| of multiple sections delimited with a dot (.). |
| |
| #. Each test identifier shall start with a section followed by a subsection |
| separated by a dot. For example, a test that covers semaphores in the kernel |
| shall start with ``kernel.semaphore``. |
| |
| #. All test identifiers within a 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. |
| |
| #. Depending on the nature of the test, an identifier can consist of at least |
| two sections: |
| |
| * Ztest tests: The individual testcases in the ztest testsuite will be |
| concatenated to identifier in the testcase.yaml file generating unique |
| identifiers for every testcase in the suite. |
| |
| * Standalone tests and samples: This type of test should at least have 3 |
| sections in the test identifier in the testcase.yaml (or sample.yaml) file. |
| The last section of the name shall signify the test itself. |
| |
| |
| Test cases are written using the YAML syntax and share the same structure as |
| samples. The following is an example test 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 |
| |
| The full canonical name for each test case is: |
| |
| :: |
| |
| <path to test case>/<test entry> |
| |
| Each test block in the testcase meta data can define the following key/value |
| pairs: |
| |
| tags: <list of tags> (required) |
| A set of string tags for the testcase. 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 testcase unconditionally. This can be used for broken tests. |
| |
| slow: <True|False> (default False) |
| Don't run this test case unless --enable-slow was passed in on the |
| command line. Intended for time-consuming test cases that are only |
| run under certain circumstances, like daily builds. These test cases |
| are still compiled. |
| |
| extra_args: <list of extra arguments> |
| Extra arguments to pass to Make when building or running the |
| test case. |
| |
| extra_configs: <list of extra configurations> |
| Extra configuration options to be merged with a master prj.conf |
| when building or running the test case. For example:: |
| |
| common: |
| tags: drivers adc |
| tests: |
| test: |
| depends_on: adc |
| test_async: |
| extra_configs: |
| - CONFIG_ADC_ASYNC=y |
| |
| |
| build_only: <True|False> (default False) |
| If true, don't try to run the test even if the |
| selected platform supports it. |
| |
| build_on_all: <True|False> (default False) |
| If true, attempt to build test on all available platforms. |
| |
| 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. |
| |
| min_ram: <integer> |
| 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> |
| 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 in QEMU before automatically killing it. |
| Default to 60 seconds. |
| |
| arch_allow: <list of arches, such as x86, arm, arc> |
| Set of architectures that this test case should only be run for. |
| |
| arch_exclude: <list of arches, such as x86, arm, arc> |
| Set of architectures that this test case should not run on. |
| |
| platform_allow: <list of platforms> |
| Set of platforms that this test case 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. |
| |
| platform_exclude: <list of platforms> |
| Set of platforms that this test case should not run on. |
| |
| 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. |
| |
| harness: <string> |
| A harness string needed to run the tests successfully. This can be as |
| simple as a loopback wiring or a complete hardware test setup for |
| sensor and IO testing. |
| Usually pertains to external dependency domains but can be anything such as |
| console, sensor, net, keyboard, Bluetooth or pytest. |
| |
| 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. |
| |
| The following options are currently supported: |
| |
| type: <one_line|multi_line> (required) |
| Depends on the regex string to be matched |
| |
| |
| record: <recording options> |
| |
| regex: <expression> (required) |
| Any string that the particular test case prints to record test |
| results. |
| |
| regex: <expression> (required) |
| Any string that the particular test case prints to confirm test |
| runs as expected. |
| |
| ordered: <True|False> (default False) |
| Check the regular expression strings in orderly or randomly fashion |
| |
| repeat: <integer> |
| Number of times to validate the repeated regex expression |
| |
| fixture: <expression> |
| Specify a test case 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. |
| |
| Only one fixture can be defined per testcase. |
| |
| pytest_root: <pytest directory> (default pytest) |
| Specify a pytest directory which need to execute when test case begin to running, |
| default pytest directory name is pytest, after pytest finished, twister will |
| check if this case pass or fail according the pytest report. |
| |
| pytest_args: <list of arguments> (default empty) |
| Specify a list of additional arguments to pass to ``pytest``. |
| |
| 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 |
| |
| The following is an example yaml file with pytest harness_config options, |
| default pytest_root name "pytest" will be used if pytest_root not specified. |
| please refer the example in samples/subsys/testsuite/pytest/. |
| |
| :: |
| |
| tests: |
| pytest.example: |
| harness: pytest |
| harness_config: |
| pytest_root: [pytest directory name] |
| |
| filter: <expression> |
| Filter whether the testcase 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 |
| } |
| |
| 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 |
| | list_contents "," 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. |
| |
| The set of test cases that actually run depends on directives in the testcase |
| filed and options passed in on the command line. If there is any confusion, |
| running with -v or examining the discard report |
| (:file:`twister_discard.csv`) can help show why particular test cases were |
| skipped. |
| |
| Metrics (such as pass/fail state and binary size) for the last code |
| release are stored in scripts/release/twister_last_release.csv. |
| To update this, pass the --all --release options. |
| |
| To load arguments from a file, write '+' 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. |
| |
| 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 testcase definition file (testcase.yaml and |
| sample.yaml). |
| |
| |
| 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:: |
| |
| scripts/twister --device-testing --device-serial /dev/ttyACM0 \ |
| --device-serial-baud 9600 -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. |
| |
| 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:: |
| |
| scripts/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. |
| |
| |
| 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:: |
| |
| ./scripts/twister --generate-hardware-map map.yml |
| |
| The generated hardware map file (map.yml) will have the list of connected |
| devices, for example:: |
| |
| - 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 both the platform names 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:: |
| |
| - 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 |
| file:: |
| |
| ./scripts/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 both pyocd and nrfjprog are supported |
| with the hardware map features. Boards that require other runners to flash the |
| Zephyr binary are still work in progress. |
| |
| Serial PTY support using ``--device-serial-pty`` can also be used in the |
| hardware map:: |
| |
| - connected: true |
| id: None |
| platform: intel_adsp_cavs18 |
| product: None |
| runner: intel_adsp |
| serial_pty: path/to/script.py |
| runner_params: |
| - --remote-host=remote_host_ip_addr |
| - --key=/path/to/key.pem |
| - 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:: |
| |
| west flash --remote-host remote_host_ip_addr --key /path/to/key.pem |
| |
| twister -p intel_adsp_cavs18 --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. |
| |
| 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 testcase 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 testcases requesting the same fixtures |
| and these tests will be executed on the boards that provide this fixture. |
| |
| .. figure:: fixtures.svg |
| :figclass: align-center |
| |
| 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 testcases which request the same fixtures. |
| |
| 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 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 |
| |
| Quarantine |
| ++++++++++ |
| |
| Twister allows using user-defined yaml files defining the list of tests 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. |
| 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 has to be a sequence of dictionaries. Each dictionary has to have |
| "scenarios" and "platforms" entries listing combinations of scenarios and platforms |
| to put under quarantine. In addition, an optional entry "comment" can be used, where |
| some more details can be given (e.g. link to a reported issue). These comments will also |
| be added to the output reports. |
| |
| An example of entries in a quarantine yaml:: |
| |
| - scenarios: |
| - sample.basic.helloworld |
| platforms: |
| - all |
| comment: "Link to the issue: https://github.com/zephyrproject-rtos/zephyr/pull/33287" |
| |
| - scenarios: |
| - kernel.common |
| - kernel.common.misra |
| - kernel.common.nano64 |
| platforms: |
| - qemu_cortex_m3 |
| - native_posix |
| |
| Running in Tests in Random Order |
| ******************************** |
| Enable ZTEST framework's :kconfig:option:`CONFIG_ZTEST_SHUFFLE` config option to |
| run your tests in random order. This can be beneficial for identifying |
| dependencies between test cases. For native_posix platforms, you can provide |
| the seed to the random number generator by providing ``-seed=value`` as an |
| argument to twister. See :ref:`Shuffling Test Sequence <ztest_shuffle>` for more |
| details. |