From d186cbe04fd3521088acaaddcd6acec9b046a156 Mon Sep 17 00:00:00 2001
From: BiffoBear <martin@martinstehens.net>
Date: Thu, 15 Dec 2022 06:19:06 +0300
Subject: [PATCH 1/7] Renamed wiznet5k_wsgiserver_test.py to
 wiznet5k_wsgiservertest.py to avoid problems with Pytest collecting tests.
 Began tests.

---
 .../{wiznet5k_wsgiserver_test.py => wiznet5k_wsgiservertest.py}   | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 rename examples/{wiznet5k_wsgiserver_test.py => wiznet5k_wsgiservertest.py} (100%)

diff --git a/examples/wiznet5k_wsgiserver_test.py b/examples/wiznet5k_wsgiservertest.py
similarity index 100%
rename from examples/wiznet5k_wsgiserver_test.py
rename to examples/wiznet5k_wsgiservertest.py

From b55bdd23c96b8293784b1ef0d462ba3a1e47823e Mon Sep 17 00:00:00 2001
From: BiffoBear <martin@martinstehens.net>
Date: Thu, 15 Dec 2022 12:13:28 +0300
Subject: [PATCH 2/7] Completed tests for __init__ and send_dhcp_message. Fixed
 two off-by-one errors in send_dhcp_message.

---
 adafruit_wiznet5k/adafruit_wiznet5k_dhcp.py |   4 +-
 tests/test_dhcp.py                          | 276 ++++++++++++++++++++
 2 files changed, 278 insertions(+), 2 deletions(-)
 create mode 100644 tests/test_dhcp.py

diff --git a/adafruit_wiznet5k/adafruit_wiznet5k_dhcp.py b/adafruit_wiznet5k/adafruit_wiznet5k_dhcp.py
index 3243f77..001cb26 100644
--- a/adafruit_wiznet5k/adafruit_wiznet5k_dhcp.py
+++ b/adafruit_wiznet5k/adafruit_wiznet5k_dhcp.py
@@ -179,7 +179,7 @@ def send_dhcp_message(
         # Transaction ID (xid)
         self._initial_xid = htonl(self._transaction_id)
         self._initial_xid = self._initial_xid.to_bytes(4, "big")
-        _BUFF[4:7] = self._initial_xid
+        _BUFF[4:8] = self._initial_xid
 
         # seconds elapsed
         _BUFF[8] = (int(time_elapsed) & 0xFF00) >> 8
@@ -195,7 +195,7 @@ def send_dhcp_message(
         # as they're already set to 0.0.0.0
         # Except when renewing, then fill in ciaddr
         if renew:
-            _BUFF[12:15] = bytes(self.local_ip)
+            _BUFF[12:16] = bytes(self.local_ip)
 
         # chaddr
         _BUFF[28:34] = self._mac_address
diff --git a/tests/test_dhcp.py b/tests/test_dhcp.py
new file mode 100644
index 0000000..4fe633b
--- /dev/null
+++ b/tests/test_dhcp.py
@@ -0,0 +1,276 @@
+# SPDX-FileCopyrightText: 2022 Martin Stephens
+#
+# SPDX-License-Identifier: MIT
+"""Tests to confirm that there are no changes in behaviour to public methods and functions."""
+
+# pylint: disable=no-self-use, redefined-outer-name, protected-access, invalid-name, too-many-arguments
+import pytest
+
+from micropython import const
+import adafruit_wiznet5k.adafruit_wiznet5k_dhcp as wiz_dhcp
+
+#
+DEFAULT_DEBUG_ON = True
+
+
+@pytest.fixture
+def wiznet(mocker):
+    return mocker.patch("adafruit_wiznet5k.adafruit_wiznet5k.WIZNET5K", autospec=True)
+
+
+@pytest.fixture
+def wrench(mocker):
+    return mocker.patch(
+        "adafruit_wiznet5k.adafruit_wiznet5k_dhcp.socket", autospec=True
+    )
+
+
+class TestDHCPInit:
+    def test_constants(self):
+        # DHCP State Machine
+        assert wiz_dhcp.STATE_DHCP_START == const(0x00)
+        assert wiz_dhcp.STATE_DHCP_DISCOVER == const(0x01)
+        assert wiz_dhcp.STATE_DHCP_REQUEST == const(0x02)
+        assert wiz_dhcp.STATE_DHCP_LEASED == const(0x03)
+        assert wiz_dhcp.STATE_DHCP_REREQUEST == const(0x04)
+        assert wiz_dhcp.STATE_DHCP_RELEASE == const(0x05)
+        assert wiz_dhcp.STATE_DHCP_WAIT == const(0x06)
+        assert wiz_dhcp.STATE_DHCP_DISCONN == const(0x07)
+
+        # DHCP wait time between attempts
+        assert wiz_dhcp.DHCP_WAIT_TIME == const(60)
+
+        # DHCP Message Types
+        assert wiz_dhcp.DHCP_DISCOVER == const(1)
+        assert wiz_dhcp.DHCP_OFFER == const(2)
+        assert wiz_dhcp.DHCP_REQUEST == const(3)
+        assert wiz_dhcp.DHCP_DECLINE == const(4)
+        assert wiz_dhcp.DHCP_ACK == const(5)
+        assert wiz_dhcp.DHCP_NAK == const(6)
+        assert wiz_dhcp.DHCP_RELEASE == const(7)
+        assert wiz_dhcp.DHCP_INFORM == const(8)
+
+        # DHCP Message OP Codes
+        assert wiz_dhcp.DHCP_BOOT_REQUEST == const(0x01)
+        assert wiz_dhcp.DHCP_BOOT_REPLY == const(0x02)
+
+        assert wiz_dhcp.DHCP_HTYPE10MB == const(0x01)
+        assert wiz_dhcp.DHCP_HTYPE100MB == const(0x02)
+
+        assert wiz_dhcp.DHCP_HLENETHERNET == const(0x06)
+        assert wiz_dhcp.DHCP_HOPS == const(0x00)
+
+        assert wiz_dhcp.MAGIC_COOKIE == const(0x63825363)
+        assert wiz_dhcp.MAX_DHCP_OPT == const(0x10)
+
+        # Default DHCP Server port
+        assert wiz_dhcp.DHCP_SERVER_PORT == const(67)
+        # DHCP Lease Time, in seconds
+        assert wiz_dhcp.DEFAULT_LEASE_TIME == const(900)
+        assert wiz_dhcp.BROADCAST_SERVER_ADDR == (255, 255, 255, 255)
+
+        # DHCP Response Options
+        assert wiz_dhcp.MSG_TYPE == 53
+        assert wiz_dhcp.SUBNET_MASK == 1
+        assert wiz_dhcp.ROUTERS_ON_SUBNET == 3
+        assert wiz_dhcp.DNS_SERVERS == 6
+        assert wiz_dhcp.DHCP_SERVER_ID == 54
+        assert wiz_dhcp.T1_VAL == 58
+        assert wiz_dhcp.T2_VAL == 59
+        assert wiz_dhcp.LEASE_TIME == 51
+        assert wiz_dhcp.OPT_END == 255
+
+        # Packet buffer
+        assert wiz_dhcp._BUFF == bytearray(318)
+
+    @pytest.mark.parametrize(
+        "mac_address",
+        (
+            [1, 2, 3, 4, 5, 6],
+            (7, 8, 9, 10, 11, 12),
+            bytes([1, 2, 4, 6, 7, 8]),
+        ),
+    )
+    def test_dhcp_setup_default(self, mocker, wiznet, wrench, mac_address):
+        # Test with mac address as tuple, list and bytes with default values.
+        mock_randint = mocker.patch(
+            "adafruit_wiznet5k.adafruit_wiznet5k_dhcp.randint", autospec=True
+        )
+        mock_randint.return_value = 0x1234567
+        dhcp_client = wiz_dhcp.DHCP(wiznet, mac_address)
+        assert dhcp_client._eth == wiznet
+        assert dhcp_client._response_timeout == 30.0
+        assert dhcp_client._debug is False
+        assert dhcp_client._mac_address == mac_address
+        wrench.set_interface.assert_called_once_with(wiznet)
+        assert dhcp_client._sock is None
+        assert dhcp_client._dhcp_state == wiz_dhcp.STATE_DHCP_START
+        assert dhcp_client._initial_xid == 0
+        mock_randint.assert_called_once()
+        assert dhcp_client._transaction_id == 0x1234567
+        assert dhcp_client._start_time == 0
+        assert dhcp_client.dhcp_server_ip == wiz_dhcp.BROADCAST_SERVER_ADDR
+        assert dhcp_client.local_ip == 0
+        assert dhcp_client.gateway_ip == 0
+        assert dhcp_client.subnet_mask == 0
+        assert dhcp_client.dns_server_ip == 0
+        assert dhcp_client._lease_time == 0
+        assert dhcp_client._last_lease_time == 0
+        assert dhcp_client._renew_in_sec == 0
+        assert dhcp_client._rebind_in_sec == 0
+        assert dhcp_client._t1 == 0
+        assert dhcp_client._t2 == 0
+        mac_string = "".join("{:02X}".format(o) for o in mac_address)
+        assert dhcp_client._hostname == bytes(
+            "WIZnet{}".split(".", maxsplit=1)[0].format(mac_string)[:42], "utf-8"
+        )
+
+    def test_dhcp_setup_other_args(self, wiznet):
+        mac_address = (7, 8, 9, 10, 11, 12)
+        dhcp_client = wiz_dhcp.DHCP(
+            wiznet, mac_address, hostname="fred.com", response_timeout=25.0, debug=True
+        )
+
+        assert dhcp_client._response_timeout == 25.0
+        assert dhcp_client._debug is True
+        mac_string = "".join("{:02X}".format(o) for o in mac_address)
+        assert dhcp_client._hostname == bytes(
+            "fred.com".split(".", maxsplit=1)[0].format(mac_string)[:42], "utf-8"
+        )
+
+
+class TestSendDHCPMessage:
+    DHCP_SEND_01 = bytearray(
+        b"\x01\x01\x06\x00\xff\xff\xffo\x00\x17\x80\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x04\x05\x06\x07"
+        b"\x08\t\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00c\x82Sc5\x01\x01="
+        b"\x07\x01\x04\x05\x06\x07\x08\t\x0c\x12WIZnet040506070809"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x007\x06\x01\x03"
+        b"\x06\x0f:;\xff\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+    )
+
+    DHCP_SEND_02 = bytearray(
+        b"\x01\x01\x06\x00\xff\xff\xffo\x00#\x80\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x18#.9DO\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00c\x82Sc5\x01\x02=\x07\x01\x18#.9DO"
+        b"\x0c\x04bert\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x007\x06"
+        b"\x01\x03\x06\x0f:;\xff\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+    )
+
+    DHCP_SEND_03 = bytearray(
+        b"\x01\x01\x06\x00\xff\xff\xffo\x00#\x80\x00\n\n\n+\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\xffa$e*c\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00c\x82Sc5\x01\x02=\x07\x01\xffa$e*c\x0c\x05cl"
+        b"ash\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x007"
+        b"\x06\x01\x03\x06\x0f:;\xff\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+    )
+
+    def test_send_with_defaults(self, wiznet, wrench):
+        assert len(wiz_dhcp._BUFF) == 318
+        dhcp_client = wiz_dhcp.DHCP(wiznet, (4, 5, 6, 7, 8, 9))
+        dhcp_client._sock = wrench.socket(type=wrench.SOCK_DGRAM)
+        dhcp_client._transaction_id = 0x6FFFFFFF
+        dhcp_client.send_dhcp_message(1, 23.4)
+        dhcp_client._sock.send.assert_called_once_with(self.DHCP_SEND_01)
+        assert len(wiz_dhcp._BUFF) == 318
+
+    @pytest.mark.parametrize(
+        "mac_address, hostname, state, time_elapsed, renew, local_ip, server_ip, result",
+        (
+            (
+                (4, 5, 6, 7, 8, 9),
+                None,
+                wiz_dhcp.STATE_DHCP_DISCOVER,
+                23.4,
+                False,
+                0,
+                0,
+                DHCP_SEND_01,
+            ),
+            (
+                (24, 35, 46, 57, 68, 79),
+                "bert.co.uk",
+                wiz_dhcp.STATE_DHCP_REQUEST,
+                35.5,
+                False,
+                (192, 168, 3, 4),
+                (222, 123, 23, 10),
+                DHCP_SEND_02,
+            ),
+            (
+                (255, 97, 36, 101, 42, 99),
+                "clash.net",
+                wiz_dhcp.STATE_DHCP_REQUEST,
+                35.5,
+                True,
+                (10, 10, 10, 43),
+                (145, 66, 45, 22),
+                DHCP_SEND_03,
+            ),
+        ),
+    )
+    def test_send_dhcp_message(
+        self,
+        wiznet,
+        wrench,
+        mac_address,
+        hostname,
+        state,
+        time_elapsed,
+        renew,
+        local_ip,
+        server_ip,
+        result,
+    ):
+        dhcp_client = wiz_dhcp.DHCP(wiznet, mac_address, hostname=hostname)
+        # Mock out socket to check what is sent
+        dhcp_client._sock = wrench.socket(type=wrench.SOCK_DGRAM)
+        # Set client attributes for test
+        dhcp_client.local_ip = local_ip
+        dhcp_client.dhcp_server_ip = server_ip
+        dhcp_client._transaction_id = 0x6FFFFFFF
+        # Test
+        dhcp_client.send_dhcp_message(state, time_elapsed, renew=renew)
+        dhcp_client._sock.send.assert_called_once_with(result)
+        assert len(wiz_dhcp._BUFF) == 318

From 6469eace1ac23e54b666e12fb8eb795bb70b7bc2 Mon Sep 17 00:00:00 2001
From: BiffoBear <martin@martinstehens.net>
Date: Thu, 15 Dec 2022 21:11:57 +0300
Subject: [PATCH 3/7] Completed tests for parse_dhcp_message. Fixed an
 off-by-one error in parse_dhcp_message and simplified MAGIC_COOKIE. Fixed
 router IP assignment to allow for multiple routers. Updated type hints.

---
 adafruit_wiznet5k/adafruit_wiznet5k_dhcp.py |  17 ++-
 tests/test_dhcp.py                          | 110 +++++++++++++++++++-
 2 files changed, 116 insertions(+), 11 deletions(-)

diff --git a/adafruit_wiznet5k/adafruit_wiznet5k_dhcp.py b/adafruit_wiznet5k/adafruit_wiznet5k_dhcp.py
index 001cb26..f3fb4ce 100644
--- a/adafruit_wiznet5k/adafruit_wiznet5k_dhcp.py
+++ b/adafruit_wiznet5k/adafruit_wiznet5k_dhcp.py
@@ -65,7 +65,7 @@
 DHCP_HLENETHERNET = const(0x06)
 DHCP_HOPS = const(0x00)
 
-MAGIC_COOKIE = const(0x63825363)
+MAGIC_COOKIE = b"c\x82Sc"  # Four bytes 99.130.83.99
 MAX_DHCP_OPT = const(0x10)
 
 # Default DHCP Server port
@@ -203,10 +203,7 @@ def send_dhcp_message(
         # NOTE:  192 octets of 0's, BOOTP legacy
 
         # Magic Cookie
-        _BUFF[236] = (MAGIC_COOKIE >> 24) & 0xFF
-        _BUFF[237] = (MAGIC_COOKIE >> 16) & 0xFF
-        _BUFF[238] = (MAGIC_COOKIE >> 8) & 0xFF
-        _BUFF[239] = MAGIC_COOKIE & 0xFF
+        _BUFF[236:240] = MAGIC_COOKIE
 
         # Option - DHCP Message Type
         _BUFF[240] = 53
@@ -262,10 +259,10 @@ def send_dhcp_message(
     # pylint: disable=too-many-branches, too-many-statements
     def parse_dhcp_response(
         self,
-    ) -> Union[Tuple[int, bytes], Tuple[int, int]]:
+    ) -> Union[Tuple[int, bytearray], Tuple[int, int]]:
         """Parse DHCP response from DHCP server.
 
-        :return Union[Tuple[int, bytes], Tuple[int, int]]: DHCP packet type.
+        :return Union[Tuple[int, bytearray], Tuple[int, int]]: DHCP packet type.
         """
         # store packet in buffer
         _BUFF = self._sock.recv()
@@ -288,7 +285,7 @@ def parse_dhcp_response(
         if _BUFF[28:34] == 0:
             return 0, 0
 
-        if int.from_bytes(_BUFF[235:240], "big") != MAGIC_COOKIE:
+        if _BUFF[236:240] != MAGIC_COOKIE:
             return 0, 0
 
         # -- Parse Packet, VARIABLE -- #
@@ -322,8 +319,8 @@ def parse_dhcp_response(
                 ptr += 1
                 opt_len = _BUFF[ptr]
                 ptr += 1
-                self.gateway_ip = tuple(_BUFF[ptr : ptr + opt_len])
-                ptr += opt_len
+                self.gateway_ip = tuple(_BUFF[ptr : ptr + 4])
+                ptr += opt_len  # still increment even though we only read 1 addr.
             elif _BUFF[ptr] == DNS_SERVERS:
                 ptr += 1
                 opt_len = _BUFF[ptr]
diff --git a/tests/test_dhcp.py b/tests/test_dhcp.py
index 4fe633b..4b2ab87 100644
--- a/tests/test_dhcp.py
+++ b/tests/test_dhcp.py
@@ -60,7 +60,7 @@ def test_constants(self):
         assert wiz_dhcp.DHCP_HLENETHERNET == const(0x06)
         assert wiz_dhcp.DHCP_HOPS == const(0x00)
 
-        assert wiz_dhcp.MAGIC_COOKIE == const(0x63825363)
+        assert wiz_dhcp.MAGIC_COOKIE == b"c\x82Sc"
         assert wiz_dhcp.MAX_DHCP_OPT == const(0x10)
 
         # Default DHCP Server port
@@ -274,3 +274,111 @@ def test_send_dhcp_message(
         dhcp_client.send_dhcp_message(state, time_elapsed, renew=renew)
         dhcp_client._sock.send.assert_called_once_with(result)
         assert len(wiz_dhcp._BUFF) == 318
+
+
+class TestParseDhcpMessage:
+
+    GOOD_DATA_01 = bytearray(
+        b"\x02\x00\x00\x00\xff\xff\xff\x7f\x00\x00\x00\x00\x00\x00\x00\x00\xc0"
+        b"\xa8\x05\x16\x00\x00\x00\x00\x00\x00\x00\x00\x01\x03\x05\x07\t\x0b\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00c\x82Sc5\x01"
+        b"\x02\x01\x04\xc0\xa8\x06\x026\x04\xeao\xde{3\x04\x00\x01\x01\x00\x03"
+        b'\x04yy\x04\x05\x06\x04\x05\x06\x07\x08:\x04\x00""\x00;\x04\x0033\x00'
+        b"\xff\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+    )
+    GOOD_DATA_02 = bytearray(
+        b"\x02\x00\x00\x00\x9axV4\x00\x00\x00\x00\x00\x00\x00\x00\x12$@\n\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00c\x82Sc5"
+        b"\x01\x05<\x05\x01\x02\x03\x04\x05\x01\x04\n\x0b\x07\xde6\x04zN\x91\x03\x03"
+        b"\x08\n\x0b\x0e\x0f\xff\x00\xff\x00\x06\x08\x13\x11\x0b\x07****3\x04\x00\x00"
+        b"=;:\x04\x00\x0e\x17@;\x04\x02\x92]\xde\xff\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+    )
+
+    @pytest.mark.parametrize(
+        "xid, local_ip, msg_type, subnet, dhcp_ip, gate_ip, dns_ip, lease, t1, t2, response",
+        (
+            (
+                0x7FFFFFFF,
+                (192, 168, 5, 22),
+                2,
+                (192, 168, 6, 2),
+                (234, 111, 222, 123),
+                (121, 121, 4, 5),
+                (5, 6, 7, 8),
+                65792,
+                2236928,
+                3355392,
+                GOOD_DATA_01,
+            ),
+            (
+                0x3456789A,
+                (18, 36, 64, 10),
+                5,
+                (10, 11, 7, 222),
+                (122, 78, 145, 3),
+                (10, 11, 14, 15),
+                (19, 17, 11, 7),
+                15675,
+                923456,
+                43146718,
+                GOOD_DATA_02,
+            ),
+        ),
+    )
+    # pylint: disable=too-many-locals
+    def test_parse_good_data(
+        self,
+        wiznet,
+        wrench,
+        xid,
+        local_ip,
+        msg_type,
+        subnet,
+        dhcp_ip,
+        gate_ip,
+        dns_ip,
+        lease,
+        t1,
+        t2,
+        response,
+    ):
+        dhcp_client = wiz_dhcp.DHCP(wiznet, (1, 2, 3, 4, 5, 6))
+        dhcp_client._sock = wrench.socket(type=wrench.SOCK_DGRAM)
+        dhcp_client._transaction_id = xid
+        dhcp_client._initial_xid = dhcp_client._transaction_id.to_bytes(4, "little")
+        dhcp_client._sock.recv.return_value = response
+        response_type, response_id = dhcp_client.parse_dhcp_response()
+        assert response_type == msg_type
+        assert response_id == bytearray(xid.to_bytes(4, "little"))
+        assert dhcp_client.local_ip == local_ip
+        assert dhcp_client.subnet_mask == subnet
+        assert dhcp_client.dhcp_server_ip == dhcp_ip
+        assert dhcp_client.gateway_ip == gate_ip
+        assert dhcp_client.dns_server_ip == dns_ip
+        assert dhcp_client._lease_time == lease
+        assert dhcp_client._t1 == t1
+        assert dhcp_client._t2 == t2

From 2161e7f9ae9e08460ac252d391f2391ec2583c63 Mon Sep 17 00:00:00 2001
From: BiffoBear <martin@martinstehens.net>
Date: Thu, 15 Dec 2022 22:03:37 +0300
Subject: [PATCH 4/7] Added tested for parse_dhcp_response failures. Fixed the
 logic for checking server ID.

---
 adafruit_wiznet5k/adafruit_wiznet5k_dhcp.py |  5 ++-
 tests/test_dhcp.py                          | 43 +++++++++++++++++++++
 2 files changed, 46 insertions(+), 2 deletions(-)

diff --git a/adafruit_wiznet5k/adafruit_wiznet5k_dhcp.py b/adafruit_wiznet5k/adafruit_wiznet5k_dhcp.py
index f3fb4ce..911bd7e 100644
--- a/adafruit_wiznet5k/adafruit_wiznet5k_dhcp.py
+++ b/adafruit_wiznet5k/adafruit_wiznet5k_dhcp.py
@@ -277,12 +277,13 @@ def parse_dhcp_response(
             DHCP message OP is not expected BOOT Reply."
 
         xid = _BUFF[4:8]
-        if bytes(xid) < self._initial_xid:
+        if bytes(xid) != self._initial_xid:
             print("f")
             return 0, 0
 
         self.local_ip = tuple(_BUFF[16:20])
-        if _BUFF[28:34] == 0:
+        # Check that there is a server ID.
+        if _BUFF[28:34] == b"\x00\x00\x00\x00\x00\x00":
             return 0, 0
 
         if _BUFF[236:240] != MAGIC_COOKIE:
diff --git a/tests/test_dhcp.py b/tests/test_dhcp.py
index 4b2ab87..566d8cd 100644
--- a/tests/test_dhcp.py
+++ b/tests/test_dhcp.py
@@ -278,6 +278,7 @@ def test_send_dhcp_message(
 
 class TestParseDhcpMessage:
 
+    # Basic case, no extra fields, one each of router and DNS.
     GOOD_DATA_01 = bytearray(
         b"\x02\x00\x00\x00\xff\xff\xff\x7f\x00\x00\x00\x00\x00\x00\x00\x00\xc0"
         b"\xa8\x05\x16\x00\x00\x00\x00\x00\x00\x00\x00\x01\x03\x05\x07\t\x0b\x00"
@@ -298,6 +299,7 @@ class TestParseDhcpMessage:
         b"\xff\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
         b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
     )
+    # Complex case, extra field, 2 each router and DNS.
     GOOD_DATA_02 = bytearray(
         b"\x02\x00\x00\x00\x9axV4\x00\x00\x00\x00\x00\x00\x00\x00\x12$@\n\x00\x00"
         b"\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
@@ -382,3 +384,44 @@ def test_parse_good_data(
         assert dhcp_client._lease_time == lease
         assert dhcp_client._t1 == t1
         assert dhcp_client._t2 == t2
+
+    BAD_DATA = bytearray(
+        b"\x02\x00\x00\x00\xff\xff\xff\x7f\x00\x00\x00\x00\x00\x00\x00\x00\x12$@\n\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00c\x82Sc"
+    )
+
+    def test_parsing_failures(self, wiznet, wrench):
+        # Test for bad OP code, ID mismatch, no server ID, bad Magic Cookie
+        dhcp_client = wiz_dhcp.DHCP(wiznet, (1, 2, 3, 4, 5, 6))
+        dhcp_client._sock = wrench.socket(type=wrench.SOCK_DGRAM)
+        dhcp_client._sock.recv.return_value = self.BAD_DATA
+        # Transaction ID mismatch.
+        dhcp_client._transaction_id = 0x42424242
+        dhcp_client._initial_xid = dhcp_client._transaction_id.to_bytes(4, "little")
+        assert dhcp_client.parse_dhcp_response() == (0, 0)
+        # Bad OP code.
+        self.BAD_DATA[0] = 0
+        dhcp_client._transaction_id = 0x7FFFFFFF
+        dhcp_client._initial_xid = dhcp_client._transaction_id.to_bytes(4, "little")
+        with pytest.raises(AssertionError):
+            # pylint: disable=expression-not-assigned
+            dhcp_client.parse_dhcp_response() == (0, 0)
+        self.BAD_DATA[0] = 2  # Reset to good value
+        # No server ID.
+        self.BAD_DATA[28:34] = (0, 0, 0, 0, 0, 0)
+        assert dhcp_client.parse_dhcp_response() == (0, 0)
+        self.BAD_DATA[28:34] = (1, 1, 1, 1, 1, 1)  # Reset to good value
+        # Bad Magic Cookie.
+        self.BAD_DATA[236] = 0
+        assert dhcp_client.parse_dhcp_response() == (0, 0)

From 449010a1230a5053cfbe303c8697bdbf63cb289f Mon Sep 17 00:00:00 2001
From: BiffoBear <martin@martinstehens.net>
Date: Thu, 15 Dec 2022 22:21:13 +0300
Subject: [PATCH 5/7] Refactored parse_dhcp_response to raise ValueError
 instead of returning 0, 0 when a problem occurs.

---
 adafruit_wiznet5k/adafruit_wiznet5k_dhcp.py | 17 +++++++----------
 tests/test_dhcp.py                          | 14 ++++++++------
 2 files changed, 15 insertions(+), 16 deletions(-)

diff --git a/adafruit_wiznet5k/adafruit_wiznet5k_dhcp.py b/adafruit_wiznet5k/adafruit_wiznet5k_dhcp.py
index 911bd7e..52e0bba 100644
--- a/adafruit_wiznet5k/adafruit_wiznet5k_dhcp.py
+++ b/adafruit_wiznet5k/adafruit_wiznet5k_dhcp.py
@@ -259,10 +259,10 @@ def send_dhcp_message(
     # pylint: disable=too-many-branches, too-many-statements
     def parse_dhcp_response(
         self,
-    ) -> Union[Tuple[int, bytearray], Tuple[int, int]]:
+    ) -> Tuple[int, bytearray]:
         """Parse DHCP response from DHCP server.
 
-        :return Union[Tuple[int, bytearray], Tuple[int, int]]: DHCP packet type.
+        :return Tuple[int, bytearray]: DHCP packet type and ID.
         """
         # store packet in buffer
         _BUFF = self._sock.recv()
@@ -271,23 +271,20 @@ def parse_dhcp_response(
 
         # -- Parse Packet, FIXED -- #
         # Validate OP
-        assert (
-            _BUFF[0] == DHCP_BOOT_REPLY
-        ), "Malformed Packet - \
-            DHCP message OP is not expected BOOT Reply."
+        if _BUFF[0] != DHCP_BOOT_REPLY:
+            raise ValueError("DHCP message OP is not expected BOOTP Reply.")
 
         xid = _BUFF[4:8]
         if bytes(xid) != self._initial_xid:
-            print("f")
-            return 0, 0
+            raise ValueError("DHCP response ID mismatch.")
 
         self.local_ip = tuple(_BUFF[16:20])
         # Check that there is a server ID.
         if _BUFF[28:34] == b"\x00\x00\x00\x00\x00\x00":
-            return 0, 0
+            raise ValueError("No DHCP server ID in the response.")
 
         if _BUFF[236:240] != MAGIC_COOKIE:
-            return 0, 0
+            raise ValueError("No DHCP Magic Cookie in the response.")
 
         # -- Parse Packet, VARIABLE -- #
         ptr = 240
diff --git a/tests/test_dhcp.py b/tests/test_dhcp.py
index 566d8cd..ccd46da 100644
--- a/tests/test_dhcp.py
+++ b/tests/test_dhcp.py
@@ -409,19 +409,21 @@ def test_parsing_failures(self, wiznet, wrench):
         # Transaction ID mismatch.
         dhcp_client._transaction_id = 0x42424242
         dhcp_client._initial_xid = dhcp_client._transaction_id.to_bytes(4, "little")
-        assert dhcp_client.parse_dhcp_response() == (0, 0)
+        with pytest.raises(ValueError):
+            dhcp_client.parse_dhcp_response()
         # Bad OP code.
         self.BAD_DATA[0] = 0
         dhcp_client._transaction_id = 0x7FFFFFFF
         dhcp_client._initial_xid = dhcp_client._transaction_id.to_bytes(4, "little")
-        with pytest.raises(AssertionError):
-            # pylint: disable=expression-not-assigned
-            dhcp_client.parse_dhcp_response() == (0, 0)
+        with pytest.raises(ValueError):
+            dhcp_client.parse_dhcp_response()
         self.BAD_DATA[0] = 2  # Reset to good value
         # No server ID.
         self.BAD_DATA[28:34] = (0, 0, 0, 0, 0, 0)
-        assert dhcp_client.parse_dhcp_response() == (0, 0)
+        with pytest.raises(ValueError):
+            dhcp_client.parse_dhcp_response()
         self.BAD_DATA[28:34] = (1, 1, 1, 1, 1, 1)  # Reset to good value
         # Bad Magic Cookie.
         self.BAD_DATA[236] = 0
-        assert dhcp_client.parse_dhcp_response() == (0, 0)
+        with pytest.raises(ValueError):
+            dhcp_client.parse_dhcp_response()

From caa5136643cb6e468803c83d128e380423a7502e Mon Sep 17 00:00:00 2001
From: BiffoBear <martin@martinstehens.net>
Date: Fri, 16 Dec 2022 11:33:04 +0300
Subject: [PATCH 6/7] Altered the _dhcp_state_machine to handle exceptions
 raised by send_dhcp_message. Added pytest to optional_requirements.txt.

---
 adafruit_wiznet5k/adafruit_wiznet5k_dhcp.py | 12 ++-
 optional_requirements.txt                   |  1 +
 tests/test_dhcp.py                          | 89 ++++++++++++++++++++-
 3 files changed, 97 insertions(+), 5 deletions(-)

diff --git a/adafruit_wiznet5k/adafruit_wiznet5k_dhcp.py b/adafruit_wiznet5k/adafruit_wiznet5k_dhcp.py
index 52e0bba..a2fb006 100644
--- a/adafruit_wiznet5k/adafruit_wiznet5k_dhcp.py
+++ b/adafruit_wiznet5k/adafruit_wiznet5k_dhcp.py
@@ -421,7 +421,11 @@ def _dhcp_state_machine(self) -> None:
             if self._sock.available():
                 if self._debug:
                     print("* DHCP: Parsing OFFER")
-                msg_type, xid = self.parse_dhcp_response()
+                try:
+                    msg_type, xid = self.parse_dhcp_response()
+                except ValueError as error:
+                    if self._debug:
+                        print(error)
                 if msg_type == DHCP_OFFER:
                     # Check if transaction ID matches, otherwise it may be an offer
                     # for another device
@@ -446,7 +450,11 @@ def _dhcp_state_machine(self) -> None:
             if self._sock.available():
                 if self._debug:
                     print("* DHCP: Parsing ACK")
-                msg_type, xid = self.parse_dhcp_response()
+                try:
+                    msg_type, xid = self.parse_dhcp_response()
+                except ValueError as error:
+                    if self._debug:
+                        print(error)
                 # Check if transaction ID matches, otherwise it may be
                 # for another device
                 if htonl(self._transaction_id) == int.from_bytes(xid, "big"):
diff --git a/optional_requirements.txt b/optional_requirements.txt
index d4e27c4..47e65a6 100644
--- a/optional_requirements.txt
+++ b/optional_requirements.txt
@@ -1,3 +1,4 @@
 # SPDX-FileCopyrightText: 2022 Alec Delaney, for Adafruit Industries
 #
 # SPDX-License-Identifier: Unlicense
+pytest
diff --git a/tests/test_dhcp.py b/tests/test_dhcp.py
index ccd46da..005e20f 100644
--- a/tests/test_dhcp.py
+++ b/tests/test_dhcp.py
@@ -2,10 +2,8 @@
 #
 # SPDX-License-Identifier: MIT
 """Tests to confirm that there are no changes in behaviour to public methods and functions."""
-
 # pylint: disable=no-self-use, redefined-outer-name, protected-access, invalid-name, too-many-arguments
 import pytest
-
 from micropython import const
 import adafruit_wiznet5k.adafruit_wiznet5k_dhcp as wiz_dhcp
 
@@ -277,7 +275,6 @@ def test_send_dhcp_message(
 
 
 class TestParseDhcpMessage:
-
     # Basic case, no extra fields, one each of router and DNS.
     GOOD_DATA_01 = bytearray(
         b"\x02\x00\x00\x00\xff\xff\xff\x7f\x00\x00\x00\x00\x00\x00\x00\x00\xc0"
@@ -427,3 +424,89 @@ def test_parsing_failures(self, wiznet, wrench):
         self.BAD_DATA[236] = 0
         with pytest.raises(ValueError):
             dhcp_client.parse_dhcp_response()
+
+
+class TestStateMachine:
+    @pytest.mark.parametrize(
+        "dhcp_state, socket_state",
+        (
+            (wiz_dhcp.STATE_DHCP_START, "Socket"),
+            (wiz_dhcp.STATE_DHCP_DISCOVER, None),
+            (wiz_dhcp.STATE_DHCP_REQUEST, None),
+            (wiz_dhcp.STATE_DHCP_LEASED, None),
+            (wiz_dhcp.STATE_DHCP_REREQUEST, None),
+            (wiz_dhcp.STATE_DHCP_RELEASE, None),
+            (wiz_dhcp.STATE_DHCP_WAIT, None),
+        ),
+    )
+    def test_link_is_down_state_not_disconnected(
+        self, mocker, wiznet, dhcp_state, socket_state
+    ):
+        dhcp_client = wiz_dhcp.DHCP(wiznet, (1, 2, 3, 4, 5, 6))
+        dhcp_client._eth.link_status = False
+        dhcp_client._eth.ifconfig = (
+            (1, 1, 1, 1),
+            (1, 1, 1, 1),
+            (1, 1, 1, 1),
+            (1, 1, 1, 1),
+        )
+        dhcp_client._last_lease_time = 1
+        dhcp_client.dhcp_server_ip = (192, 234, 1, 75)
+        dhcp_client._dhcp_state = dhcp_state
+        # If a socket exists, close() will be called, so add a Mock.
+        if socket_state is not None:
+            dhcp_client._sock = mocker.MagicMock()
+        else:
+            dhcp_client._dhcp_state = None
+        # Test.
+        dhcp_client._dhcp_state_machine()
+        # DHCP state machine in correct state.
+        assert dhcp_client._dhcp_state == wiz_dhcp.STATE_DHCP_DISCONN
+        # Check that configurations are returned to defaults.
+        assert dhcp_client._eth.ifconfig == (
+            (0, 0, 0, 0),
+            (0, 0, 0, 0),
+            (0, 0, 0, 0),
+            (0, 0, 0, 0),
+        )
+        assert dhcp_client._last_lease_time == 0
+        assert dhcp_client.dhcp_server_ip == wiz_dhcp.BROADCAST_SERVER_ADDR
+        assert dhcp_client._sock is None
+
+    def test_link_is_down_state_disconnected(self, wiznet):
+        dhcp_client = wiz_dhcp.DHCP(wiznet, (1, 2, 3, 4, 5, 6))
+        dhcp_client._eth.link_status = False
+        dhcp_client._eth.ifconfig = (
+            (1, 1, 1, 1),
+            (1, 1, 1, 1),
+            (1, 1, 1, 1),
+            (1, 1, 1, 1),
+        )
+        dhcp_client._last_lease_time = 1
+        dhcp_client.dhcp_server_ip = (192, 234, 1, 75)
+        dhcp_client._sock = "socket"
+        dhcp_client._dhcp_state = wiz_dhcp.STATE_DHCP_DISCONN
+        # Test.
+        dhcp_client._dhcp_state_machine()
+        # DHCP state machine in correct state.
+        assert dhcp_client._dhcp_state == wiz_dhcp.STATE_DHCP_DISCONN
+        # Check that configurations are not altered because state has not changed.
+        assert dhcp_client._eth.ifconfig == (
+            (1, 1, 1, 1),
+            (1, 1, 1, 1),
+            (1, 1, 1, 1),
+            (1, 1, 1, 1),
+        )
+        assert dhcp_client._last_lease_time == 1
+        assert dhcp_client.dhcp_server_ip == (192, 234, 1, 75)
+        assert dhcp_client._sock == "socket"
+
+    def test_link_is_up_state_disconnected(self, wiznet, wrench):
+        dhcp_client = wiz_dhcp.DHCP(wiznet, (1, 2, 3, 4, 5, 6))
+        wrench.socket.side_effect = [RuntimeError]
+        dhcp_client._eth.link_status = True
+        dhcp_client._dhcp_state = wiz_dhcp.STATE_DHCP_DISCONN
+        # Test.
+        dhcp_client._dhcp_state_machine()
+        # Assume state is set to START then becomes WAIT after START fails to set a socket
+        assert dhcp_client._dhcp_state == wiz_dhcp.STATE_DHCP_WAIT

From 26069eada77889ae409b4adb2c8283dcad572317 Mon Sep 17 00:00:00 2001
From: BiffoBear <martin@martinstehens.net>
Date: Fri, 16 Dec 2022 11:48:05 +0300
Subject: [PATCH 7/7] Added an else to the try statements.

---
 adafruit_wiznet5k/adafruit_wiznet5k_dhcp.py | 100 +++++++++++---------
 1 file changed, 53 insertions(+), 47 deletions(-)

diff --git a/adafruit_wiznet5k/adafruit_wiznet5k_dhcp.py b/adafruit_wiznet5k/adafruit_wiznet5k_dhcp.py
index a2fb006..1797a4c 100644
--- a/adafruit_wiznet5k/adafruit_wiznet5k_dhcp.py
+++ b/adafruit_wiznet5k/adafruit_wiznet5k_dhcp.py
@@ -426,25 +426,30 @@ def _dhcp_state_machine(self) -> None:
                 except ValueError as error:
                     if self._debug:
                         print(error)
-                if msg_type == DHCP_OFFER:
-                    # Check if transaction ID matches, otherwise it may be an offer
-                    # for another device
-                    if htonl(self._transaction_id) == int.from_bytes(xid, "big"):
-                        if self._debug:
-                            print(
-                                "* DHCP: Send request to {}".format(self.dhcp_server_ip)
+                else:
+                    if msg_type == DHCP_OFFER:
+                        # Check if transaction ID matches, otherwise it may be an offer
+                        # for another device
+                        if htonl(self._transaction_id) == int.from_bytes(xid, "big"):
+                            if self._debug:
+                                print(
+                                    "* DHCP: Send request to {}".format(
+                                        self.dhcp_server_ip
+                                    )
+                                )
+                            self._transaction_id = (
+                                self._transaction_id + 1
+                            ) & 0x7FFFFFFF
+                            self.send_dhcp_message(
+                                DHCP_REQUEST, (time.monotonic() - self._start_time)
                             )
-                        self._transaction_id = (self._transaction_id + 1) & 0x7FFFFFFF
-                        self.send_dhcp_message(
-                            DHCP_REQUEST, (time.monotonic() - self._start_time)
-                        )
-                        self._dhcp_state = STATE_DHCP_REQUEST
+                            self._dhcp_state = STATE_DHCP_REQUEST
+                        else:
+                            if self._debug:
+                                print("* DHCP: Received OFFER with non-matching xid")
                     else:
                         if self._debug:
-                            print("* DHCP: Received OFFER with non-matching xid")
-                else:
-                    if self._debug:
-                        print("* DHCP: Received DHCP Message is not OFFER")
+                            print("* DHCP: Received DHCP Message is not OFFER")
 
         elif self._dhcp_state == STATE_DHCP_REQUEST:
             if self._sock.available():
@@ -455,39 +460,40 @@ def _dhcp_state_machine(self) -> None:
                 except ValueError as error:
                     if self._debug:
                         print(error)
-                # Check if transaction ID matches, otherwise it may be
-                # for another device
-                if htonl(self._transaction_id) == int.from_bytes(xid, "big"):
-                    if msg_type == DHCP_ACK:
-                        if self._debug:
-                            print("* DHCP: Successful lease")
-                        self._sock.close()
-                        self._sock = None
-                        self._dhcp_state = STATE_DHCP_LEASED
-                        self._last_lease_time = self._start_time
-                        if self._lease_time == 0:
-                            self._lease_time = DEFAULT_LEASE_TIME
-                        if self._t1 == 0:
-                            # T1 is 50% of _lease_time
-                            self._t1 = self._lease_time >> 1
-                        if self._t2 == 0:
-                            # T2 is 87.5% of _lease_time
-                            self._t2 = self._lease_time - (self._lease_time >> 3)
-                        self._renew_in_sec = self._t1
-                        self._rebind_in_sec = self._t2
-                        self._eth.ifconfig = (
-                            self.local_ip,
-                            self.subnet_mask,
-                            self.gateway_ip,
-                            self.dns_server_ip,
-                        )
-                        gc.collect()
+                else:
+                    # Check if transaction ID matches, otherwise it may be
+                    # for another device
+                    if htonl(self._transaction_id) == int.from_bytes(xid, "big"):
+                        if msg_type == DHCP_ACK:
+                            if self._debug:
+                                print("* DHCP: Successful lease")
+                            self._sock.close()
+                            self._sock = None
+                            self._dhcp_state = STATE_DHCP_LEASED
+                            self._last_lease_time = self._start_time
+                            if self._lease_time == 0:
+                                self._lease_time = DEFAULT_LEASE_TIME
+                            if self._t1 == 0:
+                                # T1 is 50% of _lease_time
+                                self._t1 = self._lease_time >> 1
+                            if self._t2 == 0:
+                                # T2 is 87.5% of _lease_time
+                                self._t2 = self._lease_time - (self._lease_time >> 3)
+                            self._renew_in_sec = self._t1
+                            self._rebind_in_sec = self._t2
+                            self._eth.ifconfig = (
+                                self.local_ip,
+                                self.subnet_mask,
+                                self.gateway_ip,
+                                self.dns_server_ip,
+                            )
+                            gc.collect()
+                        else:
+                            if self._debug:
+                                print("* DHCP: Received DHCP Message is not ACK")
                     else:
                         if self._debug:
-                            print("* DHCP: Received DHCP Message is not ACK")
-                else:
-                    if self._debug:
-                        print("* DHCP: Received non-matching xid")
+                            print("* DHCP: Received non-matching xid")
 
         elif self._dhcp_state == STATE_DHCP_WAIT:
             if time.monotonic() > (self._start_time + DHCP_WAIT_TIME):