[BUG] unit/test-midi spurious failure

Hi all,

I get spurious failures in unit/test-midi

Debugging gives:

ALSA SysEx events to Raw BLE packets - init
ALSA SysEx events to Raw BLE packets - setup
ALSA SysEx events to Raw BLE packets - setup complete
ALSA SysEx events to Raw BLE packets - run
**
ERROR:unit/test-midi.c:287:compare_events: assertion failed (ev1->data.ext.len == ev2->data.ext.len): (5 == 4)

Program received signal SIGABRT, Aborted.
0x00007ffff746a8d7 in raise () from /lib64/libc.so.6
Missing separate debuginfos, use: zypper install libasound2-debuginfo-1.1.2-1.2.x86_64 libglib-2_0-0-debuginfo-2.48.2-1.10.x86_64 libpcre1-debuginfo-8.33-4.51.x86_64
(gdb) bt
#0  0x00007ffff746a8d7 in raise () from /lib64/libc.so.6
#1  0x00007ffff746bcaa in abort () from /lib64/libc.so.6
#2  0x00007ffff7b3bbc5 in g_assertion_message () from /usr/lib64/libglib-2.0.so.0
#3  0x00007ffff7b3bf61 in g_assertion_message_cmpnum () from /usr/lib64/libglib-2.0.so.0
#4  0x000055555555662c in compare_events (ev1=0x55555575bb20 <event4>, ev2=0x7fffffffe590) at unit/test-midi.c:285
#5  0x000055555555693b in compare_events_cb (parser=0x7fffffffe660, user_data=0x7fffffffe640) at unit/test-midi.c:577
#6  0x0000555555556bcb in test_midi_writer (data=0x55555575bb00 <midi4>) at unit/test-midi.c:603
#7  0x0000555555557878 in run_callback (user_data=0x555555763600) at src/shared/tester.c:415
#8  0x00007ffff7b18015 in g_main_context_dispatch () from /usr/lib64/libglib-2.0.so.0
#9  0x00007ffff7b18388 in ?? () from /usr/lib64/libglib-2.0.so.0
#10 0x00007ffff7b1864a in g_main_loop_run () from /usr/lib64/libglib-2.0.so.0
#11 0x0000555555558721 in tester_run () at src/shared/tester.c:830
#12 0x0000555555556429 in main (argc=1, argv=0x7fffffffe9c8) at unit/test-midi.c:631
(gdb) 

It does not happen every time, but maybe once in 10 runs,
the assertion failure numbers are different:
ERROR:unit/test-midi.c:287:compare_events: assertion failed (ev1->data.ext.len == ev2->data.ext.len): (1024 == 1023)
Aborted (core dumped)
ERROR:unit/test-midi.c:287:compare_events: assertion failed (ev1->data.ext.len == ev2->data.ext.len): (5 == 4)
Aborted (core dumped)

About one in four runs fails:

#!/bin/bash
G=0; B=0;
for i in `seq 1 1000`; do
  if unit/test-midi; then
    G=$((G+1)
  else
    B=$((B+1))
  fi
done
echo "good: $G bad: $B"

good: 730 bad: 270

I have no idea what this means, if this is an error in the
test code or a sign something is wrong with the testing system.

It started to happen with bluez-5.45, still happens with git master.
-- 
Stefan Seyfried

"For a successful technology, reality must take precedence over
 public relations, for nature cannot be fooled." -- Richard Feynman