Re: [PATCH v2] kunit: Print test statistics on failure

[David Gow <davidgow@google.com>]

On Fri, Aug 6, 2021 at 2:15 AM 'Brendan Higgins' via KUnit Development
<kunit-dev@googlegroups.com> wrote:
>
> On Tue, Aug 3, 2021 at 10:08 PM David Gow <davidgow@google.com> wrote:
> >
> > When a number of tests fail, it can be useful to get higher-level
> > statistics of how many tests are failing (or how many parameters are
> > failing in parameterised tests), and in what cases or suites. This is
> > already done by some non-KUnit tests, so add support for automatically
> > generating these for KUnit tests.
> >
> > This change adds a 'kunit.stats_enabled' switch which has three values:
> > - 0: No stats are printed (current behaviour)
> > - 1: Stats are printed only for tests/suites with more than one
> >      subtest (new default)
> > - 2: Always print test statistics
> >
> > For parameterised tests, the summary line looks as follows:
> > "    # inode_test_xtimestamp_decoding: pass:16 fail:0 skip:0 total:16"
> > For test suites, there are two lines looking like this:
> > "# ext4_inode_test: pass:1 fail:0 skip:0 total:1"
> > "# Totals: pass:16 fail:0 skip:0 total:16"
> >
> > The first line gives the number of direct subtests, the second "Totals"
> > line is the accumulated sum of all tests and test parameters.
> >
> > This format is based on the one used by kselftest[1].
> >
> > [1]: https://elixir.bootlin.com/linux/latest/source/tools/testing/selftests/kselftest.h#L109
> >
> > Signed-off-by: David Gow <davidgow@google.com>
>
> This looks great, David!
>
> My only suggestion, can you maybe provide a sample of the TAP output
> with your change running on the thread? I think it looks great, but I
> imagine that it has the potential of being more interesting to people
> other than you, Daniel, and myself rather than the actual code change.
> (To be clear, I think the summary and the code both look good, IMO.)

Sure. The lines in the commit description I think cover the actual
change pretty well:

"    # inode_test_xtimestamp_decoding: pass:16 fail:0 skip:0 total:16"

"# ext4_inode_test: pass:1 fail:0 skip:0 total:1"
"# Totals: pass:16 fail:0 skip:0 total:16"

Nevertheless, here's the complete output of the 'example' and
'rational' suites, which should give a more complete overview. (This
is with the default configuration of only printing out lines where the
number of subtests is >1)

TAP version 14
1..2
   # Subtest: example
   1..3
   # example_simple_test: initializing
   ok 1 - example_simple_test
   # example_skip_test: initializing
   # example_skip_test: You should not see a line below.
   ok 2 - example_skip_test # SKIP this test should be skipped
   # example_mark_skipped_test: initializing
   # example_mark_skipped_test: You should see a line below.
   # example_mark_skipped_test: You should see this line.
   ok 3 - example_mark_skipped_test # SKIP this test should be skipped
# example: pass:1 fail:0 skip:2 total:3
# Totals: pass:1 fail:0 skip:2 total:3
ok 1 - example
   # Subtest: rational
   1..1
   # rational_test: ok 1 - Exceeds bounds, semi-convergent term > 1/2 last term
   # rational_test: ok 2 - Exceeds bounds, semi-convergent term < 1/2 last term
   # rational_test: ok 3 - Closest to zero
   # rational_test: ok 4 - Closest to smallest non-zero
   # rational_test: ok 5 - Use convergent
   # rational_test: ok 6 - Exact answer
   # rational_test: ok 7 - Semiconvergent, numerator limit
   # rational_test: ok 8 - Semiconvergent, denominator limit
   # rational_test: pass:8 fail:0 skip:0 total:8
   ok 1 - rational_test
# Totals: pass:8 fail:0 skip:0 total:8
ok 2 - rational