| .. _chapter-pw-unit-test: |
| .. default-domain:: cpp |
| |
| .. highlight:: sh |
| |
| ------------ |
| pw_unit_test |
| ------------ |
| ``pw_unit_test`` unit testing library with a `Google Test`_-compatible API, |
| built on top of embedded-friendly primitives. |
| |
| ``pw_unit_test`` is a portable library which can run on almost any system from |
| from bare metal to a full-fledged desktop OS. It does this by offloading the |
| responsibility of test reporting and output to the underlying system, |
| communicating its results through a common interface. Unit tests can be written |
| once and run under many different environments, empowering developers to write |
| robust, high quality code. |
| |
| ``pw_unit_test`` is still under development and lacks many features expected in |
| a complete testing framework; nevertheless, it is already used heavily within |
| Pigweed. |
| |
| .. note:: |
| |
| This documentation is currently incomplete. |
| |
| Writing unit tests |
| ================== |
| |
| ``pw_unit_test``'s interface is largely compatible with `Google Test`_. Refer to |
| the Google Test documentation for examples of to define unit test cases. |
| |
| .. note:: |
| |
| A lot of Google Test's more advanced features are not yet implemented. To |
| request a feature addition, please |
| `let us know <mailto:pigweed@googlegroups.com>`_. |
| |
| Using the test framework |
| ======================== |
| |
| The EventHandler interface |
| ^^^^^^^^^^^^^^^^^^^^^^^^^^ |
| The ``EventHandler`` class in ``public/pw_unit_test/event_handler.h`` defines |
| the interface through which ``pw_unit_test`` communicates the results of its |
| test runs. A platform using ``pw_unit_test`` must register an event handler with |
| the unit testing framework to receive test output. |
| |
| As the framework runs tests, it calls the event handler's callback functions to |
| notify the system of various test events. The system can then choose to perform |
| any necessary handling or aggregation of these events, and report them back to |
| the developer. |
| |
| Predefined event handlers |
| ------------------------- |
| Pigweed provides some standard event handlers upstream to simplify the process |
| of getting started using ``pw_unit_test``. |
| |
| * ``SimplePrintingEventHandler``: An event handler that writes Google Test-style |
| output to a specified sink. |
| |
| .. code:: |
| |
| [==========] Running all tests. |
| [ RUN ] Status.Default |
| [ OK ] Status.Default |
| [ RUN ] Status.ConstructWithStatusCode |
| [ OK ] Status.ConstructWithStatusCode |
| [ RUN ] Status.AssignFromStatusCode |
| [ OK ] Status.AssignFromStatusCode |
| [ RUN ] Status.CompareToStatusCode |
| [ OK ] Status.CompareToStatusCode |
| [ RUN ] Status.Ok_OkIsTrue |
| [ OK ] Status.Ok_OkIsTrue |
| [ RUN ] Status.NotOk_OkIsFalse |
| [ OK ] Status.NotOk_OkIsFalse |
| [ RUN ] Status.KnownString |
| [ OK ] Status.KnownString |
| [ RUN ] Status.UnknownString |
| [ OK ] Status.UnknownString |
| [==========] Done running all tests. |
| [ PASSED ] 8 test(s). |
| |
| |
| * ``LoggingEventHandler``: An event handler which uses the ``pw_log`` module to |
| output test results, to integrate with the system's existing logging setup. |
| |
| .. _running-tests: |
| |
| Running tests |
| ^^^^^^^^^^^^^ |
| To run unit tests, link the tests into a single binary with the unit testing |
| framework, register an event handler, and call the ``RUN_ALL_TESTS`` macro. |
| |
| .. code:: cpp |
| |
| #include "pw_unit_test/framework.h" |
| #include "pw_unit_test/simple_printing_event_handler.h" |
| |
| void WriteString(const std::string_view& string, bool newline) { |
| printf("%s", string.data()); |
| if (newline) { |
| printf("\n"); |
| } |
| } |
| |
| int main() { |
| pw::unit_test::SimplePrintingEventHandler handler(WriteString); |
| pw::unit_test::RegisterEventHandler(&handler); |
| return RUN_ALL_TESTS(); |
| } |
| |
| Build system integration |
| ^^^^^^^^^^^^^^^^^^^^^^^^ |
| ``pw_unit_test`` integrates directly into Pigweed's GN build system. To define |
| simple unit tests, set the ``pw_unit_test_main`` build variable to a target |
| which configures the test framework as described in the :ref:`running-tests` |
| section, and use the ``pw_test`` template to register your test code. |
| |
| .. code:: |
| |
| import("$dir_pw_unit_test/test.gni") |
| |
| pw_test("foo_test") { |
| sources = [ "foo_test.cc" ] |
| } |
| |
| ``pw_unit_test`` module provides a few optional libraries to simplify setup: |
| |
| - ``simple_printing_event_handler```: When running tests, output test results |
| as plain text over ``pw_sys_io``. |
| - ``simple_printing_main``: Implements a ``main()`` function that simply runs |
| tests using the ``simple_printing_event_handler``. |
| - ``logging_event_handler``: When running tests, log test results as |
| plain text using pw_log (ensure your target has set a ``pw_log`` backend). |
| - ``logging_main``: Implements a ``main()`` function that simply runs tests |
| using the ``logging_event_handler``. |
| |
| |
| .. _Google Test: https://github.com/google/googletest/blob/master/googletest/docs/primer.md |