Re: [PATCH v8 2/3] unit tests: add TAP unit test framework

[Christian Couder <christian.couder@gmail.com>]

On Tue, Oct 10, 2023 at 12:22 AM Josh Steadmon <steadmon@google.com> wrote:
>
> From: Phillip Wood <phillip.wood@dunelm.org.uk>
>
> This patch contains an implementation for writing unit tests with TAP
> output. Each test is a function that contains one or more checks. The
> test is run with the TEST() macro and if any of the checks fail then the
> test will fail. A complete program that tests STRBUF_INIT would look
> like
>
>      #include "test-lib.h"
>      #include "strbuf.h"
>
>      static void t_static_init(void)
>      {
>              struct strbuf buf = STRBUF_INIT;
>
>              check_uint(buf.len, ==, 0);
>              check_uint(buf.alloc, ==, 0);
>              check_char(buf.buf[0], ==, '\0');
>      }
>
>      int main(void)
>      {
>              TEST(t_static_init(), "static initialization works);
>
>              return test_done();
>      }
>
> The output of this program would be
>
>      ok 1 - static initialization works
>      1..1
>
> If any of the checks in a test fail then they print a diagnostic message
> to aid debugging and the test will be reported as failing. For example a
> failing integer check would look like
>
>      # check "x >= 3" failed at my-test.c:102

I wonder if it would be a bit better to say that the test was an
integer test for example with "check_int(x >= 3) failed ..."

>      #    left: 2
>      #   right: 3

I like "expected" and "actual" better than "left" and "right", not
sure how it's possible to have that in a way consistent with the shell
tests though.

>      not ok 1 - x is greater than or equal to three
>
> There are a number of check functions implemented so far. check() checks
> a boolean condition, check_int(), check_uint() and check_char() take two
> values to compare and a comparison operator. check_str() will check if
> two strings are equal. Custom checks are simple to implement as shown in
> the comments above test_assert() in test-lib.h.

Yeah, nice.

> Tests can be skipped with test_skip() which can be supplied with a
> reason for skipping which it will print. Tests can print diagnostic
> messages with test_msg().  Checks that are known to fail can be wrapped
> in TEST_TODO().

Maybe TEST_TOFIX() would be a bit more clear, but "TODO" is something
that is more likely to be searched for than "TOFIX", so Ok.

> There are a couple of example test programs included in this
> patch. t-basic.c implements some self-tests and demonstrates the
> diagnostic output for failing test. The output of this program is
> checked by t0080-unit-test-output.sh. t-strbuf.c shows some example
> unit tests for strbuf.c
>
> The unit tests will be built as part of the default "make all" target,
> to avoid bitrot. If you wish to build just the unit tests, you can run
> "make build-unit-tests". To run the tests, you can use "make unit-tests"
> or run the test binaries directly, as in "./t/unit-tests/bin/t-strbuf".

Nice!

> +unit-tests-prove:
> +       @echo "*** prove - unit tests ***"; $(PROVE) $(GIT_PROVE_OPTS) $(UNIT_TESTS)

Nice, but DEFAULT_TEST_TARGET=prove isn't used. So not sure how
important or relevant the 'prove' related sections are in the
Documentation/technical/unit-tests.txt file introduced by the previous
patch.


> +int test_assert(const char *location, const char *check, int ok)
> +{
> +       assert(ctx.running);
> +
> +       if (ctx.result == RESULT_SKIP) {
> +               test_msg("skipping check '%s' at %s", check, location);
> +               return 1;
> +       } else if (!ctx.todo) {

I think it would be a bit clearer without the "else" above and with
the "if (!ctx.todo) {" starting on a new line.

> +               if (ok) {
> +                       test_pass();
> +               } else {
> +                       test_msg("check \"%s\" failed at %s", check, location);
> +                       test_fail();
> +               }
> +       }
> +
> +       return !!ok;
> +}

Otherwise it looks good to me.