diff --git a/test/functional/feature_cltv.py b/test/functional/feature_cltv.py
--- a/test/functional/feature_cltv.py
+++ b/test/functional/feature_cltv.py
@@ -33,9 +33,6 @@
 
 CLTV_HEIGHT = 1351
 
-# Reject codes that we might receive in this test
-REJECT_OBSOLETE = 17
-
 
 def cltv_lock_to_height(node, tx, to_address, amount, height=-1):
     '''Modify the scriptPubKey to add an OP_CHECKLOCKTIMEVERIFY, and make
diff --git a/test/functional/feature_dersig.py b/test/functional/feature_dersig.py
--- a/test/functional/feature_dersig.py
+++ b/test/functional/feature_dersig.py
@@ -16,9 +16,6 @@
 
 DERSIG_HEIGHT = 1251
 
-# Reject codes that we might receive in this test
-REJECT_OBSOLETE = 17
-
 # A canonical signature consists of:
 # <30> <total len> <02> <len R> <R> <02> <len S> <S> <hashtype>
 
diff --git a/test/functional/test_framework/messages.py b/test/functional/test_framework/messages.py
--- a/test/functional/test_framework/messages.py
+++ b/test/functional/test_framework/messages.py
@@ -39,7 +39,6 @@
 # messages (BIP37)
 MY_RELAY = 1
 
-MAX_INV_SZ = 50000
 MAX_LOCATOR_SZ = 101
 MAX_BLOCK_BASE_SIZE = 1000000
 
@@ -68,10 +67,6 @@
     return hashlib.new('sha256', s).digest()
 
 
-def ripemd160(s):
-    return hashlib.new('ripemd160', s).digest()
-
-
 def hash256(s):
     return sha256(sha256(s))
 
@@ -869,13 +864,12 @@
 
 
 class CPartialMerkleTree:
-    __slots__ = ("fBad", "nTransactions", "vBits", "vHash")
+    __slots__ = ("nTransactions", "vBits", "vHash")
 
     def __init__(self):
         self.nTransactions = 0
         self.vHash = []
         self.vBits = []
-        self.fBad = False
 
     def deserialize(self, f):
         self.nTransactions = struct.unpack("<i", f.read(4))[0]
diff --git a/test/functional/test_framework/mininode.py b/test/functional/test_framework/mininode.py
--- a/test/functional/test_framework/mininode.py
+++ b/test/functional/test_framework/mininode.py
@@ -417,7 +417,7 @@
         self.send_message(msg_pong(message.nonce))
 
     def on_verack(self, message):
-        self.verack_received = True
+        pass
 
     def on_version(self, message):
         assert message.nVersion >= MIN_VERSION_SUPPORTED, "Version {} received. Test framework only supports versions greater than {}".format(
diff --git a/test/functional/test_framework/socks5.py b/test/functional/test_framework/socks5.py
--- a/test/functional/test_framework/socks5.py
+++ b/test/functional/test_framework/socks5.py
@@ -67,10 +67,9 @@
 
 
 class Socks5Connection():
-    def __init__(self, serv, conn, peer):
+    def __init__(self, serv, conn):
         self.serv = serv
         self.conn = conn
-        self.peer = peer
 
     def handle(self):
         """Handle socks5 request according to RFC192."""
@@ -154,9 +153,9 @@
 
     def run(self):
         while self.running:
-            (sockconn, peer) = self.s.accept()
+            (sockconn, _) = self.s.accept()
             if self.running:
-                conn = Socks5Connection(self, sockconn, peer)
+                conn = Socks5Connection(self, sockconn)
                 thread = threading.Thread(None, conn.handle)
                 thread.daemon = True
                 thread.start()
diff --git a/test/functional/test_runner.py b/test/functional/test_runner.py
--- a/test/functional/test_runner.py
+++ b/test/functional/test_runner.py
@@ -779,7 +779,7 @@
         with open(coverage_ref_filename, 'r', encoding="utf8") as f:
             all_cmds.update([i.strip() for i in f.readlines()])
 
-        for root, dirs, files in os.walk(self.dir):
+        for root, _, files in os.walk(self.dir):
             for filename in files:
                 if filename.startswith(coverage_file_prefix):
                     coverage_filenames.add(os.path.join(root, filename))