Re: [PATCH v2 00/17] kunit: introduce KUnit, the Linux kernel unit testing framework

Masahiro Yamada
2019-05-09T15:20:04Z

On Thu, May 2, 2019 at 8:02 AM Brendan Higgins
<brendanhiggins@google.com> wrote:
>
> ## TLDR
>
> I rebased the last patchset on 5.1-rc7 in hopes that we can get this in
> 5.2.
>
> Shuah, I think you, Greg KH, and myself talked off thread, and we agreed
> we would merge through your tree when the time came? Am I remembering
> correctly?
>
> ## Background
>
> This patch set proposes KUnit, a lightweight unit testing and mocking
> framework for the Linux kernel.
>
> Unlike Autotest and kselftest, KUnit is a true unit testing framework;
> it does not require installing the kernel on a test machine or in a VM
> and does not require tests to be written in userspace running on a host
> kernel. Additionally, KUnit is fast: From invocation to completion KUnit
> can run several dozen tests in under a second. Currently, the entire
> KUnit test suite for KUnit runs in under a second from the initial
> invocation (build time excluded).
>
> KUnit is heavily inspired by JUnit, Python's unittest.mock, and
> Googletest/Googlemock for C++. KUnit provides facilities for defining
> unit test cases, grouping related test cases into test suites, providing
> common infrastructure for running tests, mocking, spying, and much more.
>
> ## What's so special about unit testing?
>
> A unit test is supposed to test a single unit of code in isolation,
> hence the name. There should be no dependencies outside the control of
> the test; this means no external dependencies, which makes tests orders
> of magnitudes faster. Likewise, since there are no external dependencies,
> there are no hoops to jump through to run the tests. Additionally, this
> makes unit tests deterministic: a failing unit test always indicates a
> problem. Finally, because unit tests necessarily have finer granularity,
> they are able to test all code paths easily solving the classic problem
> of difficulty in exercising error handling code.
>
> ## Is KUnit trying to replace other testing frameworks for the kernel?
>
> No. Most existing tests for the Linux kernel are end-to-end tests, which
> have their place. A well tested system has lots of unit tests, a
> reasonable number of integration tests, and some end-to-end tests. KUnit
> is just trying to address the unit test space which is currently not
> being addressed.
>
> ## More information on KUnit
>
> There is a bunch of documentation near the end of this patch set that
> describes how to use KUnit and best practices for writing unit tests.
> For convenience I am hosting the compiled docs here:
> https://google.github.io/kunit-docs/third_party/kernel/docs/
> Additionally for convenience, I have applied these patches to a branch:
> https://kunit.googlesource.com/linux/+/kunit/rfc/v5.1-rc7/v1
> The repo may be cloned with:
> git clone https://kunit.googlesource.com/linux
> This patchset is on the kunit/rfc/v5.1-rc7/v1 branch.
>
> ## Changes Since Last Version
>
> None. I just rebased the last patchset on v5.1-rc7.
>
> --
> 2.21.0.593.g511ec345e18-goog
>

The following is the log of 'git am' of this series.
I see several 'new blank line at EOF' warnings.

masahiro@pug:~/workspace/bsp/linux$ git am ~/Downloads/*.patch
Applying: kunit: test: add KUnit test runner core
Applying: kunit: test: add test resource management API
Applying: kunit: test: add string_stream a std::stream like string builder
.git/rebase-apply/patch:223: new blank line at EOF.
+
warning: 1 line adds whitespace errors.
Applying: kunit: test: add kunit_stream a std::stream like logger
Applying: kunit: test: add the concept of expectations
.git/rebase-apply/patch:475: new blank line at EOF.
+
warning: 1 line adds whitespace errors.
Applying: kbuild: enable building KUnit
Applying: kunit: test: add initial tests
.git/rebase-apply/patch:203: new blank line at EOF.
+
warning: 1 line adds whitespace errors.
Applying: kunit: test: add support for test abort
.git/rebase-apply/patch:453: new blank line at EOF.
+
warning: 1 line adds whitespace errors.
Applying: kunit: test: add tests for kunit test abort
Applying: kunit: test: add the concept of assertions
.git/rebase-apply/patch:518: new blank line at EOF.
+
warning: 1 line adds whitespace errors.
Applying: kunit: test: add test managed resource tests
Applying: kunit: tool: add Python wrappers for running KUnit tests
.git/rebase-apply/patch:457: new blank line at EOF.
+
warning: 1 line adds whitespace errors.
Applying: kunit: defconfig: add defconfigs for building KUnit tests
Applying: Documentation: kunit: add documentation for KUnit
.git/rebase-apply/patch:71: new blank line at EOF.
+
.git/rebase-apply/patch:209: new blank line at EOF.
+
.git/rebase-apply/patch:848: new blank line at EOF.
+
warning: 3 lines add whitespace errors.
Applying: MAINTAINERS: add entry for KUnit the unit testing framework
Applying: kernel/sysctl-test: Add null pointer test for sysctl.c:proc_dointvec()
Applying: MAINTAINERS: add proc sysctl KUnit test to PROC SYSCTL section

--
Best Regards
Masahiro Yamada