pytest-dev
modules: interface: return None if speed not defined
On Linux, some interfaces don't have a speed attribute, such as lo for
instance. In that case, cat /sys/class/net/lo/speed returns:
cat: /sys/class/net/lo/speed: Invalid argument
which causes Interface.speed to throw an exception.
This commit makes Interface.speed return None in those cases, instead of throwing an AssertionError.
Hi, thanks for contributing !
If the interface name does not exists it will return None as well and I think it's better to raise an error in this case.
% cat /sys/class/net/doesnotexist/speed
cat: /sys/class/net/doesnotexist/speed: No such file or directory
% echo $?
1
Maybe we should keep the current behavior and assume we can't test speed of such interfaces.
You're right, I didn't think about that. It still seems counter-intuitive to me to throw an assertion error when the speed is undefined though.
How about checking whether the interface exists or not during __init__(), since the interface properties (speed, address) don't make sense if it doesn't; the exception could be thrown there.
Otherwise, I would do assert self.exists at the beginning of speed, and then use the same logic as proposed in this PR; but it seems like we'd end up having that assertion on every single property, so having it in __init__() would be more straightforward.
Let me know what you think.
It seems to me that an except in __init__() if the interface does not exist breaks workflows that want to assert that an interface does not exist, i.e. assert not interface.exists(). Also one might use the same interface object to assert that an interface does not exist, create it externally and then assert that does exists now or the other way around.
