It was observed from a log of a failed CI test that the ACK from
clearing the rally items took 6 wallclock seconds to arrive.
We were not waiting for that ACK to arrive before sending the request
for the mission item count, but if it has taken more than six seconds
for the ACK to arrive it is reasonable to assume that MISSION_COUNT
could very well take more than the 10 seconds we allow for it.
If we drain the mav before sending the request for the mission count we
should remove any signficiant timing problem due to a backlog of mavlnk
messages, but the amount of traffic here is problematic.
Also drain in lots of other places where we might be spending way too
long parsing messages.
MAVProxy's output is read by autotest via pexpect.
SITL's output is read by MAVProxy.
If we don't read MAVProxy's stdout then it doesn't read SITL and
everything stops.
Also, since we need to drain pexpects as part of reboot, and applying
parameter files requires rebooting... we need to append the expect
objects to the global list before we apply parameter files. So move
that call.
we are in stabilize and flying around, needs more than half throttle
to maintain height. This test was already marginal, but addition of
pressure alt in SITL pushed it over the edge
This makes the AutoTest instance cognizant of the binary log files it is creating. This will be useful for checking the contents of the log files created.
Avoid SyntaxWarnings on Python >= 3.8
% `python3.8`
```
>>> "second" is "second"
<stdin>:1: SyntaxWarning: "is" with a literal. Did you mean "=="?
```
`flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics`
```
./Tools/autotest/arducopter.py:3899:20: F632 use ==/!= to compare constant literals (str, bytes, int, float, tuple)
if loop is not "second":
^
./Tools/autotest/arducopter.py:4047:20: F632 use ==/!= to compare constant literals (str, bytes, int, float, tuple)
if loop is not "second":
^
2 F632 use ==/!= to compare constant literals (str, bytes, int, float, tuple)
2
```
