RFC: Add a script to simplify finding supported properties for miio

[rytilahti]

Inspired by #808 (comment), I think it could be a good idea to have a simple script (miiotester.py stored under devtools? or simply as a command for Device?) to automate checking what a target device (i.e., which properties, and how many can be requested using a single request) supports.

This script would take a host, its token and a list of properties to test against it, so executing something like:

<tester> --host 192.168.1.2 --token 123123123 is_mop some_nonexisting_property mode water_percent some_string_property 

would query each property one by one to find out which return a valid value / do not raise an exception.
After that, the script would find out how many properties can be requested at once (to find out max_properties).

The output for this script would look something like:

# Checking for properties supported by '<model name from info()>'...

Testing 'is_mop'
<< 0

Testing 'some_nonexisting_property'
<DISPLAY THE EXCEPTION / FAILED>

Testing 'mode'
<< 4

Testing 'water_percent'
<< 123

Testing 'some_string_property'
<< "hi"

Found properties: ["is_mop", "mode", "water_percent"]

# Finding out how many properties can be requested at once...

Trying to query ["is_mop", "mode", "water_percent"]..
>> <exception / invalid number of response elements>

Trying to query ["is_mop", "mode"]..
>> [1, 4]

Maximum number of properties to query at once: 2

# Summary
* '<model>' supports properties: ["is_mop", "mode", "water_percent"]
* Maximum number of properties per request: 2

@syssi I have seen you requesting users to use raw_command on set of properties to help adding and improving support for devices, what do you think?

[jeremysherriff]

+1 a great idea

This would have saved me around 4 hours in the weekend, when I could not correlate the missing parameters to the requested parameters easily (because there were four parameters not returning results, making it complex to spot with a casual look).

I even contemplated making a simply loop to do this testing, but did not think it would take as long as it did :)

[rytilahti]

Going a bit further (i.e., not miio only) with this same idea, it is even easier to do the property enumeration for miot devices (even if there would be no schema files available): simply enumerate over the available siids and piids until an error appears to and print out the values while doing that. Someone who has a device could then map the returned values to something they are seeing in the app.

[rezmus]

device won't pass xiaomi certification without having miot specs. however with brute force way you may find some props not present in specs, but somehow implemented in firmware.