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diff --git a/test/py/README.md b/test/py/README.md new file mode 100644 index 0000000000..8036299d07 --- /dev/null +++ b/test/py/README.md @@ -0,0 +1,300 @@ +# U-Boot pytest suite + +## Introduction + +This tool aims to test U-Boot by executing U-Boot shell commands using the +console interface. A single top-level script exists to execute or attach to the +U-Boot console, run the entire script of tests against it, and summarize the +results. Advantages of this approach are: + +- Testing is performed in the same way a user or script would interact with + U-Boot; there can be no disconnect. +- There is no need to write or embed test-related code into U-Boot itself. + It is asserted that writing test-related code in Python is simpler and more + flexible that writing it all in C. +- It is reasonably simple to interact with U-Boot in this way. + +## Requirements + +The test suite is implemented using pytest. Interaction with the U-Boot console +involves executing some binary and interacting with its stdin/stdout. You will +need to implement various "hook" scripts that are called by the test suite at +the appropriate time. + +On Debian or Debian-like distributions, the following packages are required. +Similar package names should exist in other distributions. + +| Package | Version tested (Ubuntu 14.04) | +| -------------- | ----------------------------- | +| python | 2.7.5-5ubuntu3 | +| python-pytest | 2.5.1-1 | + +The test script supports either: + +- Executing a sandbox port of U-Boot on the local machine as a sub-process, + and interacting with it over stdin/stdout. +- Executing an external "hook" scripts to flash a U-Boot binary onto a + physical board, attach to the board's console stream, and reset the board. + Further details are described later. + +### Using `virtualenv` to provide requirements + +Older distributions (e.g. Ubuntu 10.04) may not provide all the required +packages, or may provide versions that are too old to run the test suite. One +can use the Python `virtualenv` script to locally install more up-to-date +versions of the required packages without interfering with the OS installation. +For example: + +```bash +$ cd /path/to/u-boot +$ sudo apt-get install python python-virtualenv +$ virtualenv venv +$ . ./venv/bin/activate +$ pip install pytest +``` + +## Testing sandbox + +To run the testsuite on the sandbox port (U-Boot built as a native user-space +application), simply execute: + +``` +./test/py/test.py --bd sandbox --build +``` + +The `--bd` option tells the test suite which board type is being tested. This +lets the test suite know which features the board has, and hence exactly what +can be tested. + +The `--build` option tells U-Boot to compile U-Boot. Alternatively, you may +omit this option and build U-Boot yourself, in whatever way you choose, before +running the test script. + +The test script will attach to U-Boot, execute all valid tests for the board, +then print a summary of the test process. A complete log of the test session +will be written to `${build_dir}/test-log.html`. This is best viewed in a web +browser, but may be read directly as plain text, perhaps with the aid of the +`html2text` utility. + +## Command-line options + +- `--board-type`, `--bd`, `-B` set the type of the board to be tested. For + example, `sandbox` or `seaboard`. +- `--board-identity`, `--id` set the identity of the board to be tested. + This allows differentiation between multiple instances of the same type of + physical board that are attached to the same host machine. This parameter is + not interpreted by the test script in any way, but rather is simply passed + to the hook scripts described below, and may be used in any site-specific + way deemed necessary. +- `--build` indicates that the test script should compile U-Boot itself + before running the tests. If using this option, make sure that any + environment variables required by the build process are already set, such as + `$CROSS_COMPILE`. +- `--build-dir` sets the directory containing the compiled U-Boot binaries. + If omitted, this is `${source_dir}/build-${board_type}`. +- `--result-dir` sets the directory to write results, such as log files, + into. If omitted, the build directory is used. +- `--persistent-data-dir` sets the directory used to store persistent test + data. This is test data that may be re-used across test runs, such as file- + system images. + +`pytest` also implements a number of its own command-line options. Please see +`pytest` documentation for complete details. Execute `py.test --version` for +a brief summary. Note that U-Boot's test.py script passes all command-line +arguments directly to `pytest` for processing. + +## Testing real hardware + +The tools and techniques used to interact with real hardware will vary +radically between different host and target systems, and the whims of the user. +For this reason, the test suite does not attempt to directly interact with real +hardware in any way. Rather, it executes a standardized set of "hook" scripts +via `$PATH`. These scripts implement certain actions on behalf of the test +suite. This keeps the test suite simple and isolated from system variances +unrelated to U-Boot features. + +### Hook scripts + +#### Environment variables + +The following environment variables are set when running hook scripts: + +- `UBOOT_BOARD_TYPE` the board type being tested. +- `UBOOT_BOARD_IDENTITY` the board identity being tested, or `na` if none was + specified. +- `UBOOT_SOURCE_DIR` the U-Boot source directory. +- `UBOOT_TEST_PY_DIR` the full path to `test/py/` in the source directory. +- `UBOOT_BUILD_DIR` the U-Boot build directory. +- `UBOOT_RESULT_DIR` the test result directory. +- `UBOOT_PERSISTENT_DATA_DIR` the test peristent data directory. + +#### `u-boot-test-console` + +This script provides access to the U-Boot console. The script's stdin/stdout +should be connected to the board's console. This process should continue to run +indefinitely, until killed. The test suite will run this script in parallel +with all other hooks. + +This script may be implemented e.g. by exec()ing `cu`, `kermit`, `conmux`, etc. + +If you are able to run U-Boot under a hardware simulator such as qemu, then +you would likely spawn that simulator from this script. However, note that +`u-boot-test-reset` may be called multiple times per test script run, and must +cause U-Boot to start execution from scratch each time. Hopefully your +simulator includes a virtual reset button! If not, you can launch the +simulator from `u-boot-test-reset` instead, while arranging for this console +process to always communicate with the current simulator instance. + +#### `u-boot-test-flash` + +Prior to running the test suite against a board, some arrangement must be made +so that the board executes the particular U-Boot binary to be tested. Often, +this involves writing the U-Boot binary to the board's flash ROM. The test +suite calls this hook script for that purpose. + +This script should perform the entire flashing process synchronously; the +script should only exit once flashing is complete, and a board reset will +cause the newly flashed U-Boot binary to be executed. + +It is conceivable that this script will do nothing. This might be useful in +the following cases: + +- Some other process has already written the desired U-Boot binary into the + board's flash prior to running the test suite. +- The board allows U-Boot to be downloaded directly into RAM, and executed + from there. Use of this feature will reduce wear on the board's flash, so + may be preferable if available, and if cold boot testing of U-Boot is not + required. If this feature is used, the `u-boot-test-reset` script should + peform this download, since the board could conceivably be reset multiple + times in a single test run. + +It is up to the user to determine if those situations exist, and to code this +hook script appropriately. + +This script will typically be implemented by calling out to some SoC- or +board-specific vendor flashing utility. + +#### `u-boot-test-reset` + +Whenever the test suite needs to reset the target board, this script is +executed. This is guaranteed to happen at least once, prior to executing the +first test function. If any test fails, the test infra-structure will execute +this script again to restore U-Boot to an operational state before running the +next test function. + +This script will likely be implemented by communicating with some form of +relay or electronic switch attached to the board's reset signal. + +The semantics of this script require that when it is executed, U-Boot will +start running from scratch. If the U-Boot binary to be tested has been written +to flash, pulsing the board's reset signal is likely all this script need do. +However, in some scenarios, this script may perform other actions. For +example, it may call out to some SoC- or board-specific vendor utility in order +to download the U-Boot binary directly into RAM and execute it. This would +avoid the need for `u-boot-test-flash` to actually write U-Boot to flash, thus +saving wear on the flash chip(s). + +### Board-type-specific configuration + +Each board has a different configuration and behaviour. Many of these +differences can be automatically detected by parsing the `.config` file in the +build directory. However, some differences can't yet be handled automatically. + +For each board, an optional Python module `u_boot_board_${board_type}` may exist +to provide board-specific information to the test script. Any global value +defined in these modules is available for use by any test function. The data +contained in these scripts must be purely derived from U-Boot source code. +Hence, these configuration files are part of the U-Boot source tree too. + +### Execution environment configuration + +Each user's hardware setup may enable testing different subsets of the features +implemented by a particular board's configuration of U-Boot. For example, a +U-Boot configuration may support USB device mode and USB Mass Storage, but this +can only be tested if a USB cable is connected between the board and the host +machine running the test script. + +For each board, optional Python modules `u_boot_boardenv_${board_type}` and +`u_boot_boardenv_${board_type}_${board_identity}` may exist to provide +board-specific and board-identity-specific information to the test script. Any +global value defined in these modules is available for use by any test +function. The data contained in these is specific to a particular user's +hardware configuration. Hence, these configuration files are not part of the +U-Boot source tree, and should be installed outside of the source tree. Users +should set `$PYTHONPATH` prior to running the test script to allow these +modules to be loaded. + +### Board module parameter usage + +The test scripts rely on the following variables being defined by the board +module: + +- None at present. + +### U-Boot `.config` feature usage + +The test scripts rely on various U-Boot `.config` features, either directly in +order to test those features, or indirectly in order to query information from +the running U-Boot instance in order to test other features. + +One example is that testing of the `md` command requires knowledge of a RAM +address to use for the test. This data is parsed from the output of the +`bdinfo` command, and hence relies on CONFIG_CMD_BDI being enabled. + +For a complete list of dependencies, please search the test scripts for +instances of: + +- `buildconfig.get(...` +- `@pytest.mark.buildconfigspec(...` + +### Complete invocation example + +Assuming that you have installed the hook scripts into $HOME/ubtest/bin, and +any required environment configuration Python modules into $HOME/ubtest/py, +then you would likely invoke the test script as follows: + +If U-Boot has already been built: + +```bash +PATH=$HOME/ubtest/bin:$PATH \ + PYTHONPATH=${HOME}/ubtest/py:${PYTHONPATH} \ + ./test/py/test.py --bd seaboard +``` + +If you want the test script to compile U-Boot for you too, then you likely +need to set `$CROSS_COMPILE` to allow this, and invoke the test script as +follow: + +```bash +CROSS_COMPILE=arm-none-eabi- \ + PATH=$HOME/ubtest/bin:$PATH \ + PYTHONPATH=${HOME}/ubtest/py:${PYTHONPATH} \ + ./test/py/test.py --bd seaboard --build +``` + +## Writing tests + +Please refer to the pytest documentation for details of writing pytest tests. +Details specific to the U-Boot test suite are described below. + +A test fixture named `u_boot_console` should be used by each test function. This +provides the means to interact with the U-Boot console, and retrieve board and +environment configuration information. + +The function `u_boot_console.run_command()` executes a shell command on the +U-Boot console, and returns all output from that command. This allows +validation or interpretation of the command output. This function validates +that certain strings are not seen on the U-Boot console. These include shell +error messages and the U-Boot sign-on message (in order to detect unexpected +board resets). See the source of `u_boot_console_base.py` for a complete list of +"bad" strings. Some test scenarios are expected to trigger these strings. Use +`u_boot_console.disable_check()` to temporarily disable checking for specific +strings. See `test_unknown_cmd.py` for an example. + +Board- and board-environment configuration values may be accessed as sub-fields +of the `u_boot_console.config` object, for example +`u_boot_console.config.ram_base`. + +Build configuration values (from `.config`) may be accessed via the dictionary +`u_boot_console.config.buildconfig`, with keys equal to the Kconfig variable +names. |