add proc-net-igmp6 parser and tests

tests/fixtures/linux-proc/net_igmp6.json

@@ -0,0 +1 @@
+[{"index":1,"name":"lo","address":"ff020000000000000000000000000001","users":1,"group":"0000000C","reporters":0},{"index":1,"name":"lo","address":"ff010000000000000000000000000001","users":1,"group":"00000008","reporters":0},{"index":2,"name":"ens33","address":"ff0200000000000000000001ffa4e315","users":1,"group":"00000004","reporters":0},{"index":2,"name":"ens33","address":"ff020000000000000000000000000001","users":2,"group":"0000000C","reporters":0},{"index":2,"name":"ens33","address":"ff010000000000000000000000000001","users":1,"group":"00000008","reporters":0}]

tests/test_proc_net_igmp6.py

@@ -0,0 +1,44 @@
+import os
+import unittest
+import json
+from typing import Dict
+import jc.parsers.proc_net_igmp6
+
+THIS_DIR = os.path.dirname(os.path.abspath(__file__))
+
+
+class MyTests(unittest.TestCase):
+    f_in: Dict = {}
+    f_json: Dict = {}
+
+    @classmethod
+    def setUpClass(cls):
+        fixtures = {
+            'proc_net_igmp6': (
+                'fixtures/linux-proc/net_igmp6',
+                'fixtures/linux-proc/net_igmp6.json')
+        }
+
+        for file, filepaths in fixtures.items():
+            with open(os.path.join(THIS_DIR, filepaths[0]), 'r', encoding='utf-8') as a, \
+                 open(os.path.join(THIS_DIR, filepaths[1]), 'r', encoding='utf-8') as b:
+                cls.f_in[file] = a.read()
+                cls.f_json[file] = json.loads(b.read())
+
+
+    def test_proc_net_igmp6_nodata(self):
+        """
+        Test 'proc_net_igmp6' with no data
+        """
+        self.assertEqual(jc.parsers.proc_net_igmp6.parse('', quiet=True), [])
+
+    def test_proc_net_igmp6(self):
+        """
+        Test '/proc/net/igmp6'
+        """
+        self.assertEqual(jc.parsers.proc_net_igmp6.parse(self.f_in['proc_net_igmp6'], quiet=True),
+                                                         self.f_json['proc_net_igmp6'])
+
+
+if __name__ == '__main__':
+    unittest.main()