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+# 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.