diff --git a/examples/protocols/mdns/mdns_example_test.py b/examples/protocols/mdns/mdns_example_test.py
index 1cd1877d6..111935291 100644
--- a/examples/protocols/mdns/mdns_example_test.py
+++ b/examples/protocols/mdns/mdns_example_test.py
@@ -3,38 +3,41 @@ import os
 import sys
 import socket
 import time
-import imp
 import struct
-import dpkt, dpkt.dns
+import dpkt
+import dpkt.dns
 from threading import Thread
 
 
-
 # this is a test case write with tiny-test-fw.
 # to run test cases outside tiny-test-fw,
 # we need to set environment variable `TEST_FW_PATH`,
 # then get and insert `TEST_FW_PATH` to sys path before import FW module
 
-test_fw_path = os.getenv("TEST_FW_PATH")
-if test_fw_path and test_fw_path not in sys.path:
-    sys.path.insert(0, test_fw_path)
+try:
+    import IDF
+except ImportError:
+    test_fw_path = os.getenv("TEST_FW_PATH")
+    if test_fw_path and test_fw_path not in sys.path:
+        sys.path.insert(0, test_fw_path)
+    import IDF
 
-import TinyFW
-import IDF
+import DUT
 
 g_run_server = True
 g_done = False
 
+
 def mdns_server(esp_host):
     global g_run_server
     global g_done
-    UDP_IP="0.0.0.0"
-    UDP_PORT=5353
+    UDP_IP = "0.0.0.0"
+    UDP_PORT = 5353
     MCAST_GRP = '224.0.0.251'
-    sock = socket.socket( socket.AF_INET, socket.SOCK_DGRAM )
+    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
     sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
     sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT, 1)
-    sock.bind( (UDP_IP,UDP_PORT) )
+    sock.bind((UDP_IP,UDP_PORT))
     mreq = struct.pack("4sl", socket.inet_aton(MCAST_GRP), socket.INADDR_ANY)
     sock.setsockopt(socket.IPPROTO_IP, socket.IP_ADD_MEMBERSHIP, mreq)
     dns = dpkt.dns.DNS(b'\x00\x00\x01\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x01\x00\x01')
@@ -47,30 +50,31 @@ def mdns_server(esp_host):
     arr.cls = dpkt.dns.DNS_IN
     arr.type = dpkt.dns.DNS_A
     arr.name = u'tinytester.local'
-    arr.ip =socket.inet_aton('127.0.0.1')
+    arr.ip = socket.inet_aton('127.0.0.1')
     resp_dns. an.append(arr)
     sock.sendto(resp_dns.pack(),(MCAST_GRP,UDP_PORT))
     while g_run_server:
         try:
-            m=sock.recvfrom( 1024 );
+            m = sock.recvfrom(1024)
             dns = dpkt.dns.DNS(m[0])
-            if len(dns.qd)>0 and dns.qd[0].type == dpkt.dns.DNS_A:
+            if len(dns.qd) > 0 and dns.qd[0].type == dpkt.dns.DNS_A:
                 if dns.qd[0].name == u'tinytester.local':
-                    print (dns.__repr__(),dns.qd[0].name)
+                    print(dns.__repr__(),dns.qd[0].name)
                     sock.sendto(resp_dns.pack(),(MCAST_GRP,UDP_PORT))
-            if len(dns.an)>0 and dns.an[0].type == dpkt.dns.DNS_A:
-                if dns.an[0].name == esp_host +  u'.local':
+            if len(dns.an) > 0 and dns.an[0].type == dpkt.dns.DNS_A:
+                if dns.an[0].name == esp_host + u'.local':
                     print("Received answer esp32-mdns query")
                     g_done = True
-                print (dns.an[0].name)
+                print(dns.an[0].name)
             dns = dpkt.dns.DNS(b'\x00\x00\x01\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x01\x00\x01')
-            dns.qd[0].name= esp_host + u'.local'
+            dns.qd[0].name = esp_host + u'.local'
             sock.sendto(dns.pack(),(MCAST_GRP,UDP_PORT))
             print("Sending esp32-mdns query")
             time.sleep(0.5)
         except socket.timeout:
             break
 
+
 @IDF.idf_example_test(env_tag="Example_WIFI")
 def test_examples_protocol_mdns(env, extra_data):
     global g_run_server
@@ -86,20 +90,19 @@ def test_examples_protocol_mdns(env, extra_data):
     # check and log bin size
     binary_file = os.path.join(dut1.app.binary_path, "mdns-test.bin")
     bin_size = os.path.getsize(binary_file)
-    IDF.log_performance("mdns-test_bin_size", "{}KB".format(bin_size//1024))
-    IDF.check_performance("mdns-test_bin_size", bin_size//1024)
+    IDF.log_performance("mdns-test_bin_size", "{}KB".format(bin_size // 1024))
+    IDF.check_performance("mdns-test_bin_size", bin_size // 1024)
     # 1. start mdns application
     dut1.start_app()
     # 2. get the dut host name (and IP address)
     specific_host = dut1.expect(re.compile(r"mdns hostname set to: \[([^\]]+)\]"), timeout=30)
     specific_host = str(specific_host[0])
-    dut_ip = ""
     try:
-        dut_ip = dut1.expect(re.compile(r" sta ip: ([^,]+),"), timeout=30)
+        dut1.expect(re.compile(r" sta ip: ([^,]+),"), timeout=30)
     except DUT.ExpectTimeout:
         raise ValueError('ENV_TEST_FAILURE: Cannot connect to AP')
     # 3. check the mdns name is accessible
-    thread1 = Thread(target = mdns_server, args = (specific_host,))
+    thread1 = Thread(target=mdns_server, args=(specific_host,))
     thread1.start()
     start = time.time()
     while (time.time() - start) <= 60:
@@ -108,10 +111,11 @@ def test_examples_protocol_mdns(env, extra_data):
             break
     g_run_server = False
     thread1.join()
-    if g_done == False:
+    if g_done is False:
         raise ValueError('Test has failed: did not receive mdns answer within timeout')
     # 4. check DUT output if mdns advertized host is resolved
     dut1.expect(re.compile(r"mdns-test: Query A: tinytester.local resolved to: 127.0.0.1"), timeout=30)
 
+
 if __name__ == '__main__':
     test_examples_protocol_mdns()