Re: [PATCH v3] tests/unit: add unit test for qemu_hexdump()

["Daniel P. Berrangé" <berrange@redhat.com>]

On Thu, Nov 13, 2025 at 01:20:15PM +0300, Vladimir Sementsov-Ogievskiy wrote:
> On 13.11.25 12:10, Daniel P. Berrangé wrote:
> > On Thu, Nov 13, 2025 at 09:49:35AM +0300, Vladimir Sementsov-Ogievskiy wrote:
> > > Test, that fix in previous commit make sense.
> > > 
> > > To not break compilation when we build without
> > > 'block', move hexdump.c out of "if have_block"
> > > in meson.build.
> > > 
> > > Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
> > > ---
> > > 
> > > v3: change meson.build to compile hexdump.c always
> > > 
> > >   tests/unit/test-cutils.c | 43 ++++++++++++++++++++++++++++++++++++++++
> > >   util/meson.build         |  2 +-
> > >   2 files changed, 44 insertions(+), 1 deletion(-)
> > 
> > > +static void test_qemu_hexdump_alignment(void)
> > > +{
> > > +    /*
> > > +     * Test that ASCII part is properly aligned for incomplete lines.
> > > +     * This test catches the bug that was fixed in previous commit
> > > +     * "util/hexdump: fix QEMU_HEXDUMP_LINE_WIDTH logic".
> > > +     *
> > > +     * We use data that is not aligned to 16 bytes, so last line
> > > +     * is incomplete.
> > > +     */
> > > +    const uint8_t data[] = {
> > > +        /* First line: 16 bytes */
> > > +        0x48, 0x65, 0x6c, 0x6c, 0x6f, 0x20, 0x57, 0x6f,  /* "Hello Wo" */
> > > +        0x72, 0x6c, 0x64, 0x21, 0x20, 0x54, 0x68, 0x69,  /* "rld! Thi" */
> > > +        /* Second line: 5 bytes (incomplete) */
> > > +        0x73, 0x20, 0x69, 0x73, 0x20                     /* "s is " */
> > > +    };
> > > +    char *output = NULL;
> > 
> > Could be  g_autofree, and avoid the later 'free()' call.
> 
> I'm not sure that it's correct to replace free() by g_free()..
> 
> Documentation says "bad things can happen" https://docs.gtk.org/glib/memory.html

Note where it says:

  "Since GLib 2.46, g_malloc() is hardcoded to always use the system
   malloc implementation."

I added that guarantee to glib docs specifically so apps no longer
have to match free with g_free.  You should still not mix up the
C free vs C++ delete, or  free vs g_slice_free, but that's not an
issue for QEMU.

> 
> > 
> > > +    size_t size;
> > > +    FILE *stream = open_memstream(&output, &size);
> > > +
> > > +    g_assert_nonnull(stream);
> > > +
> > > +    qemu_hexdump(stream, "test", data, sizeof(data));
> > > +    fclose(stream);
> > > +
> > > +    g_assert_nonnull(output);
> > > +
> > > +    /* We expect proper alignment of "s is" part on the second line */
> > > +    const char *expected =
> > > +        "test: 0000: 48 65 6c 6c  6f 20 57 6f  72 6c 64 21  20 54 68 69   Hello World! Thi\n"
> > > +        "test: 0010: 73 20 69 73  20                                      s is \n";
> > > +
> > > +    g_assert_cmpstr(output, ==, expected);
> > > +
> > > +    free(output);
> > > +}
> > 
> > The above comment is trivial, so
> > 
> >    Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
> > 
> > 
> > 
> > With regards,
> > Daniel
> 
> 
> -- 
> Best regards,
> Vladimir
> 

With regards,
Daniel
-- 
|: https://berrange.com      -o-    https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org         -o-            https://fstop138.berrange.com :|
|: https://entangle-photo.org    -o-    https://www.instagram.com/dberrange :|