diff --git a/test/test_papi.py b/test/test_papi.py
index 1a5f6ae..b5b5ac6 100644
--- a/test/test_papi.py
+++ b/test/test_papi.py
@@ -1,5 +1,7 @@
 import binascii
 from framework import VppTestCase
+from vpp_papi import VPP
+import json
 
 """ TestPAPI is a subclass of  VPPTestCase classes.
 
@@ -29,3 +31,439 @@
         node_name = 'X' * 100
         self.assertRaises(ValueError, self.v.get_node_index,
                           node_name=node_name)
+
+
+class TestPAPIMessageParsing(VppTestCase):
+    """ PAPI Message parsing Test Case """
+
+    show_version_msg = '''["show_version",
+              ["u16", "_vl_msg_id"],
+              ["u32", "client_index"],
+              ["u32", "context"],
+              {"crc" : "0xf18f9480"}
+        ]'''
+
+    ip_address_details_msg = '''["ip_address_details",
+            ["u16", "_vl_msg_id"],
+            ["u32", "client_index"],
+            ["u32", "context"],
+            ["u8", "ip", 16],
+            ["u8", "prefix_length"],
+            {"crc" : "0x87d522a1"}
+        ]'''
+
+    cli_inband_msg = '''["cli_inband",
+            ["u16", "_vl_msg_id"],
+            ["u32", "client_index"],
+            ["u32", "context"],
+            ["u32", "length"],
+            ["u8", "cmd", 0, "length"],
+            {"crc" : "0x22345937"}
+        ]'''
+
+    def test_adding_new_message_object(self):
+        p = json.loads(TestPAPIMessageParsing.show_version_msg)
+        msglist = VPP(testmode=json)
+        msgdef = msglist.add_message(p[0], p[1:])
+
+        # Verify that message can be retrieved
+        self.assertTrue(msglist['show_version'])
+        self.assertFalse(msglist['foobar'])
+
+        # Test duplicate
+        self.assertRaises(ValueError, msglist.add_message, p[0], p[1:])
+
+        # Look at return tuple
+        self.assertTrue(msglist.ret_tup('show_version'))
+
+    def test_adding_new_message_object_with_array(self):
+        p = json.loads(TestPAPIMessageParsing.ip_address_details_msg)
+        msglist = VPP(testmode=True)
+        msglist.add_message(p[0], p[1:])
+
+        self.assertTrue(msglist['ip_address_details'])
+
+    def test_message_to_bytes(self):
+        msglist = VPP(testmode=True)
+        p = json.loads(TestPAPIMessageParsing.show_version_msg)
+        msgdef = msglist.add_message(p[0], p[1:])
+
+        # Give me a byte string for given message and given arguments
+
+        b = msglist.encode(msgdef, {'_vl_msg_id': 50, 'context': 123})
+        self.assertEqual(10, len(b))
+        rv = msglist.decode(msgdef, b)
+        self.assertEqual(rv._0, 50)
+        self.assertEqual(rv.context, 123)
+
+        p = json.loads(TestPAPIMessageParsing.ip_address_details_msg)
+        msgdef = msglist.add_message(p[0], p[1:])
+
+        # Give me a byte string for given message and given arguments
+        b = msglist.encode(msgdef, {'_vl_msg_id': 50, 'context': 123,
+                                    'ip': b'\xf0\xf1\xf2',
+                                    'prefix_length': 12})
+        self.assertEqual(27, len(b))
+        rv = msglist.decode(msgdef, b)
+
+        self.assertEqual(rv.context, 123)
+        self.assertEqual(rv.ip, b'\xf0\xf1\xf2\x00\x00\x00' +
+                         '\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
+        self.assertEqual(rv.prefix_length, 12)
+
+        p = json.loads(TestPAPIMessageParsing.cli_inband_msg)
+        msgdef = msglist.add_message(p[0], p[1:])
+
+        # Give me a byte string for given message and given arguments
+        b = msglist.encode(msgdef, {'_vl_msg_id': 50, 'context': 123,
+                                    'length': 20,
+                                    'cmd': 'show version verbose'})
+        self.assertEqual(34, len(b))
+        rv = msglist.decode(msgdef, b)
+        self.assertEqual(rv._0, 50)
+        self.assertEqual(rv.context, 123)
+        self.assertEqual(rv.cmd.decode('ascii'), 'show version verbose')
+
+        variable_array_16_msg = '''["variable_array_16",
+            ["u32", "length"],
+            ["u16", "list", 0, "length"]
+        ]'''
+
+        p = json.loads(variable_array_16_msg)
+        msgdef = msglist.add_message(p[0], p[1:])
+
+        # Give me a byte string for given message and given arguments
+        b = msglist.encode(msgdef, {'list': [1, 2], 'length': 2})
+        self.assertEqual(8, len(b))
+        rv = msglist.decode(msgdef, b)
+        self.assertEqual(2, rv.length)
+        self.assertEqual([1, 2], rv.list)
+
+    def test_add_new_types(self):
+        counter_type = '''["ip4_fib_counter",
+            ["u32", "address"],
+            ["u8", "address_length"],
+            ["u64", "packets"],
+            ["u64", "bytes"],
+            {"crc" : "0xb2739495"}
+        ]'''
+
+        with_type_msg = '''["with_type_msg",
+            ["u32", "length"],
+            ["u16", "list", 0, "length"],
+            ["vl_api_ip4_fib_counter_t", "counter"]
+        ]'''
+
+        # Add new type
+        msglist = VPP(testmode=True)
+        p = json.loads(counter_type)
+        msglist.add_type(p[0], p[1:])
+        p = json.loads(with_type_msg)
+        msgdef = msglist.add_message(p[0], p[1:])
+        b = msglist.encode(msgdef, {'length': 2, 'list': [1, 2],
+                                    'counter': {'address': 4,
+                                                'address_length': 12,
+                                                'packets': 1235,
+                                                'bytes': 5678}})
+        self.assertEqual(29, len(b))
+        rv = msglist.decode(msgdef, b)
+        self.assertEqual(2, rv.length)
+        self.assertEqual(5678, rv.counter.bytes)
+
+    def test_add_two_new_types(self):
+        mock_r1 = '''["mock_r1",
+            ["u32", "a1"],
+            {"crc" : "0xb2739495"}
+        ]'''
+        mock_r2 = '''["mock_r2",
+            ["u32", "a1"],
+            {"crc" : "0xb2739495"}
+        ]'''
+
+        mock_msg = '''["mock_msg",
+            ["u32", "context"],
+            ["i32", "retval"],
+            ["vl_api_mock_r1_t", "r1"],
+            ["vl_api_mock_r2_t", "r2"],
+            {"crc" : "0xb2739495"}
+        ]'''
+
+        # Add new type
+        msglist = VPP(testmode=True)
+        p = json.loads(mock_r1)
+        msglist.add_type(p[0], p[1:])
+        p = json.loads(mock_r2)
+        msglist.add_type(p[0], p[1:])
+        p = json.loads(mock_msg)
+        msgdef = msglist.add_message(p[0], p[1:])
+        b = msglist.encode(msgdef, {'context': 2, 'retval': 0,
+                                    'r1': {'a1': 4}, 'r2': {'a1': 12}})
+
+        self.assertEqual(16, len(b))
+        rv = msglist.decode(msgdef, b)
+        self.assertEqual(4, rv.r1.a1)
+
+    def test_nested_array_type(self):
+        bier_type = '''["bier_table_id",
+            ["u8", "bt_set"],
+            ["u8", "bt_sub_domain"],
+            ["u8", "bt_hdr_len_id"],
+            {"crc" : "0xb2739495"}
+        ]'''
+        fib_path3 = '''["fib_path3",
+            ["u32", "sw_if_index"],
+            ["u8", "n_labels"],
+            ["u32", "label_stack", 0, "n_labels"],
+            {"crc" : "0xb2739495"}
+        ]'''
+
+        bier_route_details = '''["bier_route_details",
+            ["u32", "client_index"],
+            ["vl_api_bier_table_id_t", "br_tbl_id"],
+            ["u32", "br_n_paths"],
+            ["vl_api_fib_path3_t", "br_paths", 0, "br_n_paths"],
+            {"crc" : "0xb2739495"}
+        ]'''
+
+        # Add new type
+        msglist = VPP(testmode=True)
+
+        p = json.loads(bier_type)
+        msglist.add_type(p[0], p[1:])
+        p = json.loads(fib_path3)
+        msglist.add_type(p[0], p[1:])
+
+        p = json.loads(bier_route_details)
+        msgdef = msglist.add_message(p[0], p[1:])
+
+        bt_tbl_id = {'bt_set': 1, 'bt_sub_domain': 2, 'bt_hdr_len_id': 3}
+        fib_path = {'sw_if_index': 1, 'n_labels': 2,
+                    'label_stack': [123, 456]}
+
+        b = msglist.encode(msgdef, {'client_index': 2,
+                                    'br_tbl_id': bt_tbl_id,
+                                    'br_n_paths': 2,
+                                    'br_paths': [fib_path, fib_path]})
+        self.assertEqual(37, len(b))
+        rv = msglist.decode(msgdef, b)
+        self.assertEqual([123, 456], rv.br_paths[1].label_stack)
+        self.assertEqual(bt_tbl_id['bt_set'], rv.br_tbl_id.bt_set)
+
+    def test_add_new_compound_type_with_array(self):
+        counter_type = '''["ip4_fib_counter",
+            ["u32", "address"],
+            ["u8", "address_length"],
+            ["u64", "packets"],
+            ["u64", "bytes"],
+            {"crc" : "0xb2739495"}
+        ]'''
+
+        with_type_msg = '''["with_type_msg",
+            ["u32", "length"],
+            ["u16", "list", 0, "length"],
+            ["vl_api_ip4_fib_counter_t", "counter", 2]
+
+        ]'''
+
+        # Add new type
+        msglist = VPP(testmode=True)
+        p = json.loads(counter_type)
+        msglist.add_type(p[0], p[1:])
+        p = json.loads(with_type_msg)
+        msgdef = msglist.add_message(p[0], p[1:])
+        b = msglist.encode(msgdef, {'length': 2, 'list': [1, 2],
+                                    'counter': [{'address': 4,
+                                                 'address_length': 12,
+                                                 'packets': 1235,
+                                                 'bytes': 5678},
+                                                {'address': 111,
+                                                 'address_length': 222,
+                                                 'packets': 333,
+                                                 'bytes': 444}]})
+        self.assertEqual(50, len(b))
+        rv = msglist.decode(msgdef, b)
+        self.assertEqual([1, 2], rv.list)
+        self.assertEqual(1235, rv.counter[0].packets)
+
+        with_type_variable_msg = '''["with_type_variable_msg",
+            ["u32", "length"],
+            ["vl_api_ip4_fib_counter_t", "counter", 0, "length"]
+
+        ]'''
+
+        p = json.loads(with_type_variable_msg)
+        msgdef = msglist.add_message(p[0], p[1:])
+        b = msglist.encode(msgdef, {'length': 2,
+                                    'counter': [{'address': 4,
+                                                 'address_length': 12,
+                                                 'packets': 1235,
+                                                 'bytes': 5678},
+                                                {'address': 111,
+                                                 'address_length': 222,
+                                                 'packets': 333,
+                                                 'bytes': 444}]})
+        self.assertEqual(46, len(b))
+        rv = msglist.decode(msgdef, b)
+        self.assertEqual(2, rv.length)
+        self.assertEqual(1235, rv.counter[0].packets)
+        self.assertEqual(333, rv.counter[1].packets)
+
+    def test_simple_array(self):
+        msglist = VPP(testmode=True)
+
+        simple_byte_array = '''["simple_byte_array",
+            ["u32", "length"],
+            ["u8", "namecommand", 64]
+
+        ]'''
+        p = json.loads(simple_byte_array)
+        msgdef = msglist.add_message(p[0], p[1:])
+        b = msglist.encode(msgdef, {'length': 2, 'namecommand': 'foobar'})
+        self.assertEqual(68, len(b))
+        rv = msglist.decode(msgdef, b)
+        self.assertEqual(2, rv.length)
+
+        simple_array = '''["simple_array",
+            ["u32", "length"],
+            ["u32", "list", 2]
+
+        ]'''
+        p = json.loads(simple_array)
+        msgdef = msglist.add_message(p[0], p[1:])
+        b = msglist.encode(msgdef, {'length': 2, 'list': [1, 2]})
+        self.assertEqual(12, len(b))
+        rv = msglist.decode(msgdef, b)
+        self.assertEqual(2, rv.length)
+        self.assertEqual([1, 2], rv.list)
+
+        simple_variable_array = '''["simple_variable_array",
+            ["u32", "length"],
+            ["u32", "list", 0, "length"]
+
+        ]'''
+        p = json.loads(simple_variable_array)
+        msgdef = msglist.add_message(p[0], p[1:])
+        b = msglist.encode(msgdef, {'length': 2, 'list': [1, 2]})
+        self.assertEqual(12, len(b))
+        rv = msglist.decode(msgdef, b)
+        self.assertEqual(2, rv.length)
+        self.assertEqual([1, 2], rv.list)
+
+        simple_variable_byte_array = '''["simple_variable_byte_array",
+            ["u32", "length"],
+            ["u8", "list", 0, "length"]
+        ]'''
+        p = json.loads(simple_variable_byte_array)
+        msgdef = msglist.add_message(p[0], p[1:])
+        b = msglist.encode(msgdef, {'length': 6, 'list': 'foobar'})
+        self.assertEqual(10, len(b))
+        rv = msglist.decode(msgdef, b)
+        self.assertEqual(6, rv.length)
+        self.assertEqual('foobar', rv.list)
+
+    def test_old_vla_array(self):
+        msglist = VPP(testmode=True)
+
+        # VLA
+        vla_byte_array = '''["vla_byte_array",
+            ["u32", "foobar"],
+            ["u32", "list", 2],
+            ["u32", "propercount"],
+            ["u8", "propermask", 0, "propercount"],
+            ["u8", "oldmask", 0],
+            {"crc" : "0xb2739495"}
+        ]'''
+        p = json.loads(vla_byte_array)
+        msgdef = msglist.add_message(p[0], p[1:])
+        b = msglist.encode(msgdef, {'list': [123, 456], 'oldmask': b'foobar',
+                                    'propercount': 2,
+                                    'propermask': [8, 9]})
+        self.assertEqual(24, len(b))
+        rv = msglist.decode(msgdef, b)
+        self.assertEqual(b'foobar', rv.oldmask)
+
+    def test_old_vla_array_not_last_member(self):
+        msglist = VPP(testmode=True)
+
+        # VLA
+        vla_byte_array = '''["vla_byte_array",
+            ["u8", "oldmask", 0],
+            ["u32", "foobar"],
+            {"crc" : "0xb2739495"}
+        ]'''
+        p = json.loads(vla_byte_array)
+        self.assertRaises(ValueError, msglist.add_message, p[0], p[1:])
+
+    def test_old_vla_array_u32(self):
+        msglist = VPP(testmode=True)
+
+        # VLA
+        vla_byte_array = '''["vla_byte_array",
+            ["u32", "foobar"],
+            ["u32", "oldmask", 0],
+            {"crc" : "0xb2739495"}
+        ]'''
+        p = json.loads(vla_byte_array)
+        msgdef = msglist.add_message(p[0], p[1:])
+        b = msglist.encode(msgdef, {'foobar': 123,
+                                    'oldmask': [123, 456, 789]})
+        self.assertEqual(16, len(b))
+        rv = msglist.decode(msgdef, b)
+        self.assertEqual([123, 456, 789], rv.oldmask)
+
+    def test_old_vla_array_compound(self):
+        msglist = VPP(testmode=True)
+
+        # VLA
+        counter_type = '''["ip4_fib_counter",
+            ["u32", "address"],
+            ["u8", "address_length"],
+            ["u64", "packets"],
+            ["u64", "bytes"],
+            {"crc" : "0xb2739495"}
+        ]'''
+
+        vla_byte_array = '''["vla_byte_array",
+            ["vl_api_ip4_fib_counter_t", "counter", 0],
+            {"crc" : "0xb2739495"}
+        ]'''
+
+        p = json.loads(counter_type)
+        msglist.add_type(p[0], p[1:])
+
+        p = json.loads(vla_byte_array)
+        with self.assertRaises(NotImplementedError):
+            msgdef = msglist.add_message(p[0], p[1:])
+
+    def test_array_count_not_previous(self):
+        msglist = VPP(testmode=True)
+
+        # VLA
+        vla_byte_array = '''["vla_byte_array",
+            ["u32", "count"],
+            ["u32", "filler"],
+            ["u32", "lst", 0, "count"],
+            {"crc" : "0xb2739495"}
+        ]'''
+
+        p = json.loads(vla_byte_array)
+        msgdef = msglist.add_message(p[0], p[1:])
+        b = msglist.encode(msgdef, {'count': 3, 'lst': [1, 2, 3],
+                                    'filler': 1})
+        rv = msglist.decode(msgdef, b)
+        self.assertEqual(rv.lst, [1, 2, 3])
+
+    def test_argument_name(self):
+        msglist = VPP(testmode=True)
+
+        simple_name = '''["simple_name",
+            ["u32", "length"],
+            ["u8", "name"]
+        ]'''
+        p = json.loads(simple_name)
+        msgdef = msglist.add_message(p[0], p[1:])
+        b = msglist.encode(msgdef, {'length': 6, 'name': 1})
+        self.assertEqual(5, len(b))
+        rv = msglist.decode(msgdef, b)
+        self.assertEqual(6, rv.length)
+        self.assertEqual(1, rv.name)