diff mbox series

[v3] guides: add a guide for developing unit tests

Message ID 20210309155757.615536-1-aconole@redhat.com (mailing list archive)
State New
Delegated to: Thomas Monjalon
Headers show
Series [v3] guides: add a guide for developing unit tests | expand

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ci/github-robot success github build: passed
ci/travis-robot success travis build: passed
ci/intel-Testing success Testing PASS
ci/Intel-compilation success Compilation OK
ci/checkpatch success coding style OK

Commit Message

Aaron Conole March 9, 2021, 3:57 p.m. UTC
The DPDK testing infrastructure includes a comprehensive set of
libraries, utilities, and CI integrations for developers to test
their code changes.  This isn't well documented, however.

Document the basics for adding a test suite to the infrastructure
and enabling that test suite for continuous integration platforms
so that newer developers can understand how to develop test suites
and test cases.

Reviewed-by: David Marchand <david.marchand@redhat.com>
Signed-off-by: Aaron Conole <aconole@redhat.com>
---
v0->v1: Added information for TEST_SKIPPED and details about generating
        code coverage to help with ideas for writing unit test cases.
v1->v2: Corrected some spelling, rephrased a bit after suggestions by
        Ray.
v2->v3: Rewrite the meson build block, updated the copyright section,
        and change the title to be a bit nicer

 doc/guides/contributing/index.rst   |   1 +
 doc/guides/contributing/testing.rst | 243 ++++++++++++++++++++++++++++
 2 files changed, 244 insertions(+)
 create mode 100644 doc/guides/contributing/testing.rst
diff mbox series

Patch

diff --git a/doc/guides/contributing/index.rst b/doc/guides/contributing/index.rst
index 2fefd91931..41909d949b 100644
--- a/doc/guides/contributing/index.rst
+++ b/doc/guides/contributing/index.rst
@@ -14,6 +14,7 @@  Contributor's Guidelines
     abi_versioning
     documentation
     patches
+    testing
     vulnerability
     stable
     cheatsheet
diff --git a/doc/guides/contributing/testing.rst b/doc/guides/contributing/testing.rst
new file mode 100644
index 0000000000..0757d71ad0
--- /dev/null
+++ b/doc/guides/contributing/testing.rst
@@ -0,0 +1,243 @@ 
+..  SPDX-License-Identifier: BSD-3-Clause
+    Copyright 2021 The DPDK contributors
+
+DPDK Testing Guidelines
+=======================
+
+This document outlines the guidelines for running and adding new
+tests to the in-tree DPDK test suites.
+
+The DPDK test suite model is loosely based on the xunit model, where
+tests are grouped into test suites, and suites are run by runners.
+For a basic overview, see the basic Wikipedia article on xunit:
+`xUnit - Wikipedia <https://en.wikipedia.org/wiki/XUnit>`_.
+
+
+Running a test
+--------------
+
+DPDK tests are run via the main test runner, the `dpdk-test` app.
+The `dpdk-test` app is a command-line interface that facilitates
+running various tests or test suites.
+
+There are two modes of operation.  The first mode is as an interactive
+command shell that allows launching specific test suites.  This is
+the default operating mode of `dpdk-test` and can be done by::
+
+  $ ./build/app/test/dpdk-test --dpdk-options-here
+  EAL: Detected 4 lcore(s)
+  EAL: Detected 1 NUMA nodes
+  EAL: Static memory layout is selected, amount of reserved memory can be adjusted with -m or --socket-mem
+  EAL: Multi-process socket /run/user/26934/dpdk/rte/mp_socket
+  EAL: Selected IOVA mode 'VA'
+  EAL: Probing VFIO support...
+  EAL: PCI device 0000:00:1f.6 on NUMA socket -1
+  EAL:   Invalid NUMA socket, default to 0
+  EAL:   probe driver: 8086:15d7 net_e1000_em
+  APP: HPET is not enabled, using TSC as default timer
+  RTE>>
+
+At the prompt, simply type the name of the test suite you wish to run
+and it will execute.
+
+The second form is useful for a scripting environment, and is used by
+the DPDK meson build system.  This mode is invoked by assigning a
+specific test suite name to the environment variable `DPDK_TEST`
+before invoking the `dpdk-test` command, such as::
+
+  $ DPDK_TEST=version_autotest ./build/app/test/dpdk-test --dpdk-options-here
+  EAL: Detected 4 lcore(s)
+  EAL: Detected 1 NUMA nodes
+  EAL: Static memory layout is selected, amount of reserved memory can be adjusted with -m or --socket-mem
+  EAL: Multi-process socket /run/user/26934/dpdk/rte/mp_socket
+  EAL: Selected IOVA mode 'VA'
+  EAL: Probing VFIO support...
+  EAL: PCI device 0000:00:1f.6 on NUMA socket -1
+  EAL:   Invalid NUMA socket, default to 0
+  EAL:   probe driver: 8086:15d7 net_e1000_em
+  APP: HPET is not enabled, using TSC as default timer
+  RTE>>version_autotest
+  Version string: 'DPDK 20.02.0-rc0'
+  Test OK
+  RTE>>$
+
+The above shows running a specific test case.  On success, the return
+code will be '0', otherwise it will be set to some error value (such
+as '255').
+
+
+Running all tests
+-----------------
+
+In order to allow developers to quickly execute all the standard
+internal tests without needing to remember or look up each test suite
+name, the build system includes a standard way of executing the
+default test suites.  After building via `ninja`, the ``meson test``
+command will execute the standard tests and report errors.
+
+There are four groups of default test suites.  The first group is
+the **fast** test suite, which is the largest group of test cases.
+These are the bulk of the unit tests to validate functional blocks.
+The second group is the **perf** tests.  These test suites can take
+longer to run and do performance evaluations.  The third group is
+the **driver** test suite, which is mostly for special hardware
+related testing (such as `cryptodev`).  The last group are the
+**debug** tests.  These mostly are used to dump system information.
+
+The suites can be selected by adding the ``--suite`` option to the
+``meson test`` command.  Ex: ``meson test --suite fast-tests``::
+
+  $ meson test -C build --suite fast-tests
+  ninja: Entering directory `/home/aconole/git/dpdk/build'
+  [2543/2543] Linking target app/test/dpdk-test.
+  1/60 DPDK:fast-tests / acl_autotest          OK       3.17 s
+  2/60 DPDK:fast-tests / bitops_autotest       OK       0.22 s
+  3/60 DPDK:fast-tests / byteorder_autotest    OK       0.22 s
+  4/60 DPDK:fast-tests / cmdline_autotest      OK       0.28 s
+  5/60 DPDK:fast-tests / common_autotest       OK       0.57 s
+  6/60 DPDK:fast-tests / cpuflags_autotest     OK       0.27 s
+  ...
+
+
+Adding test suites
+------------------
+
+To add a test suite to the DPDK test application, create a new test
+file for that suite (ex: see *app/test/test_version.c* for the
+``version_autotest`` test suite).  There are two important functions
+for interacting with the test harness:
+
+  1. REGISTER_TEST_COMMAND(command_name, function_to_execute)
+     Registers a test command with the name `command_name` and which
+     runs the function `function_to_execute` when `command_name` is
+     invoked.
+
+  2. unit_test_suite_runner(struct unit_test_suite \*)
+     Returns a runner for a full test suite object, which contains
+     a test suite name, setup, tear down, and vector of unit test
+     cases.
+
+Each test suite has a setup and tear down function that runs at the
+beginning and end of the test suite execution.  Each unit test has
+a similar function for test case setup and tear down.
+
+Test cases are added to the `.unit_test_cases` element of the unit
+test suite structure.  Ex:
+
+.. code-block:: c
+   :linenos:
+
+   #include <time.h>
+
+   #include <rte_common.h>
+   #include <rte_cycles.h>
+   #include <rte_hexdump.h>
+   #include <rte_random.h>
+
+   #include "test.h"
+
+   static int testsuite_setup(void) { return TEST_SUCCESS; }
+   static void testsuite_teardown(void) { }
+
+   static int ut_setup(void) { return TEST_SUCCESS; }
+   static void ut_teardown(void) { }
+
+   static int test_case_first(void) { return TEST_SUCCESS; }
+
+   static struct unit_test_suite example_testsuite = {
+          .suite_name = "EXAMPLE TEST SUITE",
+          .setup = testsuite_setup,
+          .teardown = testsuite_teardown,
+          .unit_test_cases = {
+               TEST_CASE_ST(ut_setup, ut_teardown, test_case_first),
+
+               TEST_CASES_END(), /**< NULL terminate unit test array */
+          },
+   };
+
+   static int example_tests()
+   {
+       return unit_test_suite_runner(&example_testsuite);
+   }
+
+   REGISTER_TEST_COMMAND(example_autotest, example_tests);
+
+The above code block is a small example that can be used to create a
+complete test suite with test case.
+
+
+Designing a test
+----------------
+
+Test cases have multiple ways of indicating an error has occurred,
+in order to reflect failure state back to the runner.  Using the
+various methods of indicating errors can assist in not only validating
+the requisite functionality is working, but also to help debug when
+a change in environment or code has caused things to go wrong.
+
+The first way to indicate a generic error is by returning a test
+result failure, using the *TEST_FAILED* error code.  This is the most
+basic way of indicating that an error has occurred in a test routine.
+It isn't very informative to the user, so it should really be used in
+cases where the test has catastrophically failed.
+
+The preferred method of indicating an error is via the
+`RTE_TEST_ASSERT` family of macros, which will immediately return
+*TEST_FAILED* error condition, but will also log details about the
+failure.  The basic form is:
+
+.. code-block:: c
+
+   RTE_TEST_ASSERT(cond, msg, ...)
+
+In the above macro, *cond* is the condition to evaluate to **true**.
+Any generic condition can go here.  The *msg* parameter will be a
+message to display if *cond* evaluates to **false**.  Some specialized
+macros already exist.  See `lib/librte_eal/include/rte_test.h` for
+a list of defined test assertions.
+
+Sometimes it is important to indicate that a test needs to be
+skipped, either because the environment isn't able to support running
+the test, or because some requisite functionality isn't available.  The
+test suite supports returning a result of `TEST_SKIPPED` during test
+case setup, or during test case execution to indicate that the
+preconditions of the test aren't available.  Ex::
+
+  $ meson test -C build --suite fast-tests
+  ninja: Entering directory `/home/aconole/git/dpdk/build
+  [2543/2543] Linking target app/test/dpdk-test.
+  1/60 DPDK:fast-tests / acl_autotest          OK       3.17 s
+  2/60 DPDK:fast-tests / bitops_autotest       OK       0.22 s
+  3/60 DPDK:fast-tests / byteorder_autotest    OK       0.22 s
+  ...
+  46/60 DPDK:fast-tests / ipsec_autotest       SKIP     0.22 s
+  ...
+
+
+Checking code coverage
+----------------------
+The meson build system supports generating a code coverage report
+via the `-Db_coverage=true` option, in conjunction with a package
+like **lcov**, to generate an HTML code coverage report.  Example::
+
+  $ meson setup build -Db_coverage=true
+  $ meson test -C build --suite fast-tests
+  $ ninja coverage-html -C build
+
+The above will generate an html report in the
+`build/meson-logs/coveragereport/` directory that can be explored
+for detailed code covered information.  This can be used to assist
+in test development.
+
+
+Adding a suite to the default
+-----------------------------
+
+Adding to one of the default tests involves editing the appropriate
+meson build file `app/test/meson.build` and adding the command to
+the correct test suite class.  Once added, the new test suite will
+be run as part of the appropriate class (fast, perf, driver, etc.).
+
+Some of these default test suites are run during continuous integration
+tests, making regression checking automatic for new patches submitted
+to the project.