Re: [PATCH v5 bpf-next 2/3] selftests/bpf: add ASSERT_STRNEQ() variant for test_progs

From: Andrii Nakryiko <andrii.nakryiko@gmail.com>
To: Alan Maguire <alan.maguire@oracle.com>
Cc: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>, Martin Lau <kafai@fb.com>,
	Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
	john fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@kernel.org>, Bill Wendling <morbo@google.com>,
	Shuah Khan <shuah@kernel.org>, bpf <bpf@vger.kernel.org>,
	Networking <netdev@vger.kernel.org>,
	"open list:KERNEL SELFTEST FRAMEWORK" 
	<linux-kselftest@vger.kernel.org>,
	open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v5 bpf-next 2/3] selftests/bpf: add ASSERT_STRNEQ() variant for test_progs
Date: Tue, 6 Jul 2021 20:32:49 -0700	[thread overview]
Message-ID: <CAEf4BzabCuTcA4jPsp+hYboCnr74PptL7hjZtm3HX1j0SJ2YSw@mail.gmail.com> (raw)
In-Reply-To: <1624092968-5598-3-git-send-email-alan.maguire@oracle.com>

On Sat, Jun 19, 2021 at 1:56 AM Alan Maguire <alan.maguire@oracle.com> wrote:
>
> It will support strncmp()-style string comparisons.
>
> Suggested-by: Andrii Nakryiko <andrii.nakryiko@gmail.com>
> Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
> ---
>  tools/testing/selftests/bpf/test_progs.h | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
>
> diff --git a/tools/testing/selftests/bpf/test_progs.h b/tools/testing/selftests/bpf/test_progs.h
> index 8ef7f33..d2944da 100644
> --- a/tools/testing/selftests/bpf/test_progs.h
> +++ b/tools/testing/selftests/bpf/test_progs.h
> @@ -221,6 +221,18 @@ struct test_env {
>         ___ok;                                                          \
>  })
>
> +#define ASSERT_STRNEQ(actual, expected, len, name) ({                  \
> +       static int duration = 0;                                        \
> +       const char *___act = actual;                                    \
> +       const char *___exp = expected;                                  \
> +       size_t ___len = len;                                            \
> +       bool ___ok = strncmp(___act, ___exp, ___len) == 0;              \
> +       CHECK(!___ok, (name),                                           \
> +             "unexpected %s: actual '%s' != expected '%s'\n",          \
> +             (name), ___act, ___exp);                                  \

it would be nice to only emit what we are actually comparing - first n
characters of each string. Luckily, printf is cool enough to support
this:

printf("actual '%.*s' != expected '%.*s'\n", ___len, ___act, ___len, ___exp);

> +       ___ok;                                                          \
> +})
> +
>  #define ASSERT_OK(res, name) ({                                                \
>         static int duration = 0;                                        \
>         long long ___res = (res);                                       \
> --
> 1.8.3.1
>