Re: [RFC v3 17/19] of: unittest: migrate tests to run on KUnit

From: Brendan Higgins
Date: Wed Feb 27 2019 - 19:29:19 EST

On Mon, Feb 18, 2019 at 2:56 PM Frank Rowand <frowand.list@xxxxxxxxx> wrote:
>
> On 2/12/19 5:44 PM, Brendan Higgins wrote:
> > On Wed, Nov 28, 2018 at 12:56 PM Rob Herring <robh@xxxxxxxxxx> wrote:
> >>
> >> On Wed, Nov 28, 2018 at 1:38 PM Brendan Higgins
> >> <brendanhiggins@xxxxxxxxxx> wrote:
<snip>
> >>> ---
> >>> drivers/of/Kconfig | 1 +
> >>> drivers/of/unittest.c | 1405 ++++++++++++++++++++++-------------------
> >>> 2 files changed, 752 insertions(+), 654 deletions(-)
> >>>
> > <snip>
> >>> diff --git a/drivers/of/unittest.c b/drivers/of/unittest.c
> >>> index 41b49716ac75f..a5ef44730ffdb 100644
> >>> --- a/drivers/of/unittest.c
> >>> +++ b/drivers/of/unittest.c
<snip>
> >>> +
> >>> + KUNIT_EXPECT_EQ(test,
> >>> + of_property_match_string(np,
> >>> + "phandle-list-names",
> >>> + "first"),
> >>> + 0);
> >>> + KUNIT_EXPECT_EQ(test,
> >>> + of_property_match_string(np,
> >>> + "phandle-list-names",
> >>> + "second"),
> >>> + 1);
> >>
> >> Fewer lines on these would be better even if we go over 80 chars.
>
> Agreed. unittest.c already is a greater than 80 char file in general, and
> is a file that benefits from that.
>

Noted.

>
> > On the of_property_match_string(...), I have no opinion. I will do
> > whatever you like best.
> >
> > Nevertheless, as far as the KUNIT_EXPECT_*(...), I do have an opinion: I am
> > trying to establish a good, readable convention. Given an expect statement
> > structured as
> > ```
> > KUNIT_EXPECT_*(
> > test,
> > expect_arg_0, ..., expect_arg_n,
> > fmt_str, fmt_arg_0, ..., fmt_arg_n)
> > ```
> > where `test` is the `struct kunit` context argument, `expect_arg_{0, ..., n}`
> > are the arguments the expectations is being made about (so in the above example,
> > `of_property_match_string(...)` and `1`), and `fmt_*` is the optional format
> > string that comes at the end of some expectations.
> >
> > The pattern I had been trying to promote is the following:
> >
> > 1) If everything fits on 1 line, do that.
> > 2) If you must make a line split, prefer to keep `test` on its own line,
> > `expect_arg_{0, ..., n}` should be kept together, if possible, and the format
> > string should follow the conventions already most commonly used with format
> > strings.
> > 3) If you must split up `expect_arg_{0, ..., n}` each argument should get its
> > own line and should not share a line with either `test` or any `fmt_*`.
> >
> > The reason I care about this so much is because expectations should be
> > extremely easy to read; they are the most important part of a unit
> > test because they tell you what the test is verifying. I am not
> > married to the formatting I proposed above, but I want something that
> > will be extremely easy to identify the arguments that the expectation
> > is on. Maybe that means that I need to add some syntactic fluff to
> > make it clearer, I don't know, but this is definitely something we
> > need to get right, especially in the earliest examples.
>
> I will probably raise the ire of the kernel formatting rule makers by offering
> what I think is a _much_ more readable format __for this specific case__.
> In other words for drivers/of/unittest.c.
>
> If you can not make your mail window _very_ wide, or if this email has been
> line wrapped, this example will not be clear.
>
> Two possible formats:
>
>
> ### ----- version 1, as created by the patch series
>
> static void of_unittest_property_string(struct kunit *test)
> {
> const char *strings[4];
> struct device_node *np;
> int rc;
>
> np = of_find_node_by_path("/testcase-data/phandle-tests/consumer-a");
> KUNIT_ASSERT_NOT_ERR_OR_NULL(test, np);
>
> KUNIT_EXPECT_EQ(
> test,
> of_property_match_string(np, "phandle-list-names", "first"),
> 0);
> KUNIT_EXPECT_EQ(
> test,
> of_property_match_string(np, "phandle-list-names", "second"),
> 1);
> KUNIT_EXPECT_EQ(
> test,
> of_property_match_string(np, "phandle-list-names", "third"),
> 2);
> KUNIT_EXPECT_EQ_MSG(
> test,
> of_property_match_string(np, "phandle-list-names", "fourth"),
> -ENODATA,
> "unmatched string");
> KUNIT_EXPECT_EQ_MSG(
> test,
> of_property_match_string(np, "missing-property", "blah"),
> -EINVAL,
> "missing property");
> KUNIT_EXPECT_EQ_MSG(
> test,
> of_property_match_string(np, "empty-property", "blah"),
> -ENODATA,
> "empty property");
> KUNIT_EXPECT_EQ_MSG(
> test,
> of_property_match_string(np, "unterminated-string", "blah"),
> -EILSEQ,
> "unterminated string");
>
> /* of_property_count_strings() tests */
> KUNIT_EXPECT_EQ(test,
> of_property_count_strings(np, "string-property"), 1);
> KUNIT_EXPECT_EQ(test,
> of_property_count_strings(np, "phandle-list-names"), 3);
> KUNIT_EXPECT_EQ_MSG(
> test,
> of_property_count_strings(np, "unterminated-string"), -EILSEQ,
> "unterminated string");
> KUNIT_EXPECT_EQ_MSG(
> test,
> of_property_count_strings(np, "unterminated-string-list"),
> -EILSEQ,
> "unterminated string array");
>
>
>
>
> ### ----- version 2, modified to use really long lines
>
> static void of_unittest_property_string(struct kunit *test)
> {
> const char *strings[4];
> struct device_node *np;
> int rc;
>
> np = of_find_node_by_path("/testcase-data/phandle-tests/consumer-a");
> KUNIT_ASSERT_NOT_ERR_OR_NULL(test, np);
>
> KUNIT_EXPECT_EQ( test, of_property_match_string(np, "phandle-list-names", "first"), 0);
> KUNIT_EXPECT_EQ( test, of_property_match_string(np, "phandle-list-names", "second"), 1);
> KUNIT_EXPECT_EQ( test, of_property_match_string(np, "phandle-list-names", "third"), 2);
> KUNIT_EXPECT_EQ_MSG(test, of_property_match_string(np, "phandle-list-names", "fourth"), -ENODATA, "unmatched string");
> KUNIT_EXPECT_EQ_MSG(test, of_property_match_string(np, "missing-property", "blah"), -EINVAL, "missing property");
> KUNIT_EXPECT_EQ_MSG(test, of_property_match_string(np, "empty-property", "blah"), -ENODATA, "empty property");
> KUNIT_EXPECT_EQ_MSG(test, of_property_match_string(np, "unterminated-string", "blah"), -EILSEQ, "unterminated string");
>
> /* of_property_count_strings() tests */
> KUNIT_EXPECT_EQ( test, of_property_count_strings(np, "string-property"), 1);
> KUNIT_EXPECT_EQ( test, of_property_count_strings(np, "phandle-list-names"), 3);
> KUNIT_EXPECT_EQ_MSG(test, of_property_count_strings(np, "unterminated-string"), -EILSEQ, "unterminated string");
> KUNIT_EXPECT_EQ_MSG(test, of_property_count_strings(np, "unterminated-string-list"), -EILSEQ, "unterminated string array");
>
>
> ------------------------ ------------------------------------------------------------- --------------------------------------
> ^ ^ ^
> | | |
> | | |
> mostly boilerplate what is being tested expected result, error message
> (can vary in relop
> and _MSG or not)
>
> In my opinion, the second version is much more readable. It is easy to see the
> differences in the boilerplate. It is easy to see what is being tested, and how
> the arguments of the tested function vary for each test. It is easy to see the
> expected result and error message. The entire block fits into a single short
> window (though much wider).

I have no opinion on the over 80 char thing, so as long as everyone
else is okay with it, I have no complaints.

Cheers