Re: [PATCH bpf-next v1 5/8] selftests/bpf: bad_struct_ops test

[Eduard Zingerman <eddyz87@gmail.com>]

On Wed, 2024-02-28 at 15:40 -0800, Andrii Nakryiko wrote:
[...]

> > +static libbpf_print_fn_t old_print_cb;
> > +static bool msg_found;
> > +
> > +static int print_cb(enum libbpf_print_level level, const char *fmt, va_list args)
> > +{
> > +       old_print_cb(level, fmt, args);
> > +       if (level == LIBBPF_WARN && strncmp(fmt, EXPECTED_MSG, strlen(EXPECTED_MSG)) == 0)
> > +               msg_found = true;
> > +
> > +       return 0;
> > +}
> > +
> > +static void test_bad_struct_ops(void)
> > +{
> > +       struct bad_struct_ops *skel;
> > +       int err;
> > +
> > +       old_print_cb = libbpf_set_print(print_cb);
> > +       skel = bad_struct_ops__open_and_load();
> 
> we want to check that the load step failed specifically, right? So
> please split open from load, make sure that open succeeds, but load
> fails

Ok

> 
> > +       err = errno;
> > +       libbpf_set_print(old_print_cb);
> > +       if (!ASSERT_NULL(skel, "bad_struct_ops__open_and_load"))
> > +               return;
> > +
> > +       ASSERT_EQ(err, EINVAL, "errno should be EINVAL");
> > +       ASSERT_TRUE(msg_found, "expected message");
> > +
> > +       bad_struct_ops__destroy(skel);
> > +}
> > +
> > +void serial_test_bad_struct_ops(void)
> 
> why does it have to be a serial test?

Because it hijacks libbpf print callback.

[...]