Add xml GetError

[edenhaus]

@sandervankasteel To go on with adding the xml commands, I think the best would be to split the PR #288 into smaller pieces. I have extracted the GetError command into this PR. Could you please test it?

[codecov]

Codecov Report

Attention: 3 lines in your changes are missing coverage. Please review.

Comparison is base (422b51a) 78.60% compared to head (c772dfd) 82.08%.
Report is 16 commits behind head on dev.

Files	Patch %	Lines
deebot_client/message.py	84.61%	1 Missing and 1 partial ⚠️
deebot_client/commands/xml/common.py	95.65%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##              dev     #369      +/-   ##
==========================================
+ Coverage   78.60%   82.08%   +3.47%     
==========================================
  Files          64       68       +4     
  Lines        2618     2768     +150     
  Branches      475      504      +29     
==========================================
+ Hits         2058     2272     +214     
+ Misses        516      447      -69     
- Partials       44       49       +5     

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[lukakama]

@edenhaus Just tested the PR successfully on both newer T20 Omni (json) and older Ozmo 900 (xml). For the latter I had to define a device class named "y79a7u" with no capabilities except the error one, but it worked.
For both i checked the "no errors", "off the floor" and "removed bin" statuses. They should be enough for the T20 Omni to assert no regressions.
For more advanced tests on the Ozmo 900 I need more time. Let me know if they are needed.

[edenhaus]

@lukakama Thanks for testing and you need only to test this command on the 900 as it is a XML command. It should never be used for a json model like the new bots.

Can you please share me the capabilities file of the 900, so I will add it directly with this PR :)

[lukakama]

For T20 I tested the JSON version of GetError command, as I noticed that it has been impacted by refactors needed to support the XML version (the externalization of error constants). It was just to assert absence of (imho very unlikely) regressions :P .

The capability file instead is just a sort of placeholder to perform a local test, which also does not honor type hints... Anyway, here it is:

y79a7u.py

"""Deebot Ozmo 900 Capabilities."""

from deebot_client.capabilities import (
    Capabilities,
    CapabilityEvent,
)
from deebot_client.const import DataType
from deebot_client.events import (
    ErrorEvent,
)
from deebot_client.models import StaticDeviceInfo
from deebot_client.util import short_name

from . import DEVICES

DEVICES[short_name(__name__)] = StaticDeviceInfo(
    DataType.XML,
    Capabilities(
        availability=None,
        battery=None,
        charge=None,
        clean=None,
        custom=None,
        error=CapabilityEvent(ErrorEvent, [GetError()]),
        fan_speed=None,
        life_span=None,
        map=None,
        network=None,
        play_sound=None,
        settings=None,
        state=None,
        stats=None,
        water=None,
    ),
)