Parse using device output

Parsergen now supports working without passing the device as an argument, user can pass the device output (as a string) along with the OS (for abstraction purpose) instead.

def test_non_tabular_parser(self):

    """
        Test non tabular parser when passing a device output
        and device os only and compare against selected tags.
    """

    pure_cli = dedent(self.showCommandOutput1)

    attrValPairsToCheck = [
        ('show.intf.if_name',                       'MgmtEth0/0/CPU0/0'),
        ('show.intf.line_protocol',                 'up'),
        ('show.intf.ip_address',                    '10.30.108.132'),
        ('show.intf.mtu',                           1514),
        ('show.intf.admin_state',                   'up'),
    ]

    device_os = 'iosxr'

    pgcheck = oper_check (
                attrvalpairs = attrValPairsToCheck,
                show_command = \
                    ('show_interface_<WORD>', [], {'ifname':'MgmtEth0/0/CPU0/0'}),
                refresh_cache=True,
                device_output = pure_cli,
                device_os = device_os)

    result = pgcheck.parse()
    self.assertTrue(result)
    self.assertEqual(parsergen.ext_dictio['device_name'], self.outputDict2)

def test_tabular_parser(self):

    """
        Test tabular parser when passing a device output
        and device os only.
    """

    pure_cli='''
        Interface              IP-Address      OK? Method Status                Protocol
        GigabitEthernet0/0     10.1.10.20      YES NVRAM  up                    up
        GigabitEthernet1/0/1   unassigned      YES unset  up                    up
        GigabitEthernet1/0/10  unassigned      YES unset  down                  down
    '''
    device_os = 'iosxe'

    res = parsergen.oper_fill_tabular(header_fields=
                                        [ "Interface",
                                          "IP-Address",
                                          "OK\?",
                                          "Method",
                                          "Status",
                                          "Protocol" ],
                                      label_fields=
                                        [ "Interface",
                                          "IP-Address",
                                          "OK?",
                                          "Method",
                                          "Status",
                                          "Protocol" ],
                                      index=[ 0, 5 ],
                                      device_output = pure_cli,
                                      device_os = device_os)

    self.assertEqual(res.entries, outputDict4)

    outputDict4 = {
        'GigabitEthernet0/0':
            {'up':
                {'IP-Address': '10.1.10.20',
                 'Interface': 'GigabitEthernet0/0',
                 'Method': 'NVRAM',
                 'OK?': 'YES',
                 'Protocol': 'up',
                 'Status': 'up'}},
        'GigabitEthernet1/0/1':
            {'up':
                {'IP-Address': 'unassigned',
                 'Interface': 'GigabitEthernet1/0/1',
                 'Method': 'unset',
                 'OK?': 'YES',
                 'Protocol': 'up',
                 'Status': 'up'}},
        'GigabitEthernet1/0/10':
            {'down':
                {'IP-Address': 'unassigned',
                 'Interface': 'GigabitEthernet1/0/10',
                 'Method': 'unset',
                 'OK?': 'YES',
                 'Protocol': 'down',
                 'Status': 'down'}}}