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

Brendan Higgins
2019-05-10T10:25:20Z

> 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

Sorry about this! I will have it fixed on the next revision.