test_interfaces.py

#! /usr/bin/env python3
# -*- coding: utf-8 -*-

# test class interfaces.PhysicalInterace

from interfaces import PhysicalInterface
from unittest.mock import patch


def fake_run_ip_link_command(interface=None) -> dict:
    """
    This subroutine is to be run instead of the real
    PhysicalInterfaces.run_ip_link_command
    :param interface: str   name of the interface to test
    :return:
    """

    if interface == "eno1":
        answer = {"eno1": "<NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 "
                          r"qdisc fq_codel state DOWN mode DEFAULT group default "
                          r"qlen 1000\      link/ether 00:22:4d:7c:4d:d9 "
                          r"brd ff:ff:ff:ff:ff:ff\ "
                          r"RX: bytes  packets  errors  dropped overrun mcast   \    0"
                          r" \ 0        0       0       0       0       \    "
                          r"TX: bytes  packets  errors  dropped carrier collsns \ "
                          r"0          0        0       0       0       0"}
        return answer
    else:
        # This must be a dict, and not a string
        return {interface: f"Haven't done {interface} yet."}


def test_interfaces():
    mocked_interface = "eno1"       # Use a real interface name here.  The real function will return real results
    print(f"The object ID of the fake_run_ip_link_command method is {id(fake_run_ip_link_command)}")
    print(
        f"The object ID of the interfaces.PhysicalInterface.run_ip_link_command is "
        f"{id(PhysicalInterface.run_ip_link_command)}")
    print(f"Before patching, the results of the PhysicalInterface.run_ip_link_command call on {mocked_interface} is:\n" + str(
        PhysicalInterface.run_ip_link_command(mocked_interface)))
    with patch("interfaces.PhysicalInterface.run_ip_link_command") as run_ip_link_command_mock:
        # fake_run_ip_link_command is not a call, it's a callable

        # When I set the run_ip_link_command_mock.return_value to a dictionary,
        # I get a good result.  It is only if I set the run_ip_link_command_mock.return_value
        # to a callable that I run into a problem
        run_ip_link_command_mock.return_value = \
            {"eno1": "<NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 "
                     r"qdisc fq_codel state DOWN mode DEFAULT group default "
                     r"qlen 1000\      link/ether 00:22:4d:7c:4d:d9 "
                     r"brd ff:ff:ff:ff:ff:ff\ "
                     r"RX: bytes  packets  errors  dropped overrun mcast   \    0"
                     r" \ 0        0       0       0       0       \    "
                     r"TX: bytes  packets  errors  dropped carrier collsns \ "
                     r"0          0        0       0       0       0"}
            # fake_run_ip_link_command
        print(
            f"After patching, the object ID of the interfaces.PhysicalInterface.run_ip_link_command is "
            f"{id(PhysicalInterface.run_ip_link_command)}")
        if_properties_dict = PhysicalInterface.run_ip_link_command(mocked_interface)
        if callable(if_properties_dict):
            print(f"if_properties_dict is callable.  If we call it,\n{if_properties_dict()} . ")
            print(f"If we call it with {mocked_interface}: {PhysicalInterface.run_ip_link_command(mocked_interface)}.")
        assert isinstance(if_properties_dict, dict), \
            f"if_properties_dict should be a dict, but it's really a " + \
            str(type(if_properties_dict))
        print(if_properties_dict)