regress: use non blocking descriptors whenever it is possible Next tests uses fds without O_NONBLOCK flag - main/free_active_base - main/many_events - et/et (has some other bits cleaned up by using TT_* flags and test setup/cleanup callbacks) And hence they will fail in debug mode (EVENT_DEBUG_MODE=): Assertion flags & O_NONBLOCK failed in event_debug_assert_socket_nonblocking_