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SubjectRe: [PATCH v2 2/7] arch: um: add linker section for KUnit test suites
On 1/30/20 5:08 PM, Brendan Higgins wrote:
> Add a linker section to UML where KUnit can put references to its test
> suites. This patch is an early step in transitioning to dispatching all
> KUnit tests from a centralized executor rather than having each as its
> own separate late_initcall.

All architectures please.

The early versions of Kunit documented reliance on UML. Discussion lead to
the conclusion that real architectures and real hardware would be supported.

This like this are what make me reluctant to move devicetree unittests to

Can you please add a section to the KUnit documentation that lists things
like the expectations, requirements, limitations, etc for a test case that
is run by KUnit? Some examples that pop to mind from recent discussions
and my own experiences:

- Each test case is invoked after late_init is complete.
+ Exception: the possible value of being able to run a unit test
at a specific runlevel has been expressed. If an actual unit
test can be shown to require running earlier, this restriction
will be re-visited.

- Each test case must be idempotent. Each test case may be called
multiple times, and must generate the same result each time it
is called.
+ Exception 1: a test case can be declared to not be idempotent
[[ mechanism TBD ]], in which case KUnit will not call the
test case a second time without the kernel rebooting.
+ Exception 2: hardware may not be deterministic, so a test that
always passes or fails when run under UML may not always to
so on real hardware. <--- sentence copied from
[[ This item and 1st exception do not exist yet, but will exist
in some form if the proposed proc filesystem interface is
added. ]]

- KUnit provides a helpful wrapper to simplify building a UML kernel
containing the KUnit test cases, booting the UML kernel, and
formatting the output from the test cases. This wrapper MUST NOT
be required to run the test cases or to determine a test result.
The formatting may provide additional analysis and improve
readability of a test result.

- .... There is more that belongs here, but I'm getting side tracked
here, when I'm trying to instead convert devicetree unittests to
KUnit and want to get back to that.


> Signed-off-by: Brendan Higgins <>
> Reviewed-by: Stephen Boyd <>
> ---
> arch/um/include/asm/ | 4 ++++
> 1 file changed, 4 insertions(+)
> diff --git a/arch/um/include/asm/ b/arch/um/include/asm/
> index 7145ce6999822..eab9ceb450efd 100644
> --- a/arch/um/include/asm/
> +++ b/arch/um/include/asm/
> @@ -52,6 +52,10 @@
> }
> + .kunit_test_suites : {
> + }
> +
> .exitcall : {
> __exitcall_begin = .;
> *(.exitcall.exit)

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