diff --git a/test/functional/interface_bitcoin_cli.py b/test/functional/interface_bitcoin_cli.py
--- a/test/functional/interface_bitcoin_cli.py
+++ b/test/functional/interface_bitcoin_cli.py
@@ -4,7 +4,11 @@
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 """Test bitcoin-cli"""
 from test_framework.test_framework import BitcoinTestFramework
-from test_framework.util import assert_equal, assert_raises_process_error, get_auth_cookie
+from test_framework.util import (
+    assert_equal,
+    assert_raises_process_error,
+    get_auth_cookie,
+)
 
 
 class TestBitcoinCli(BitcoinTestFramework):
diff --git a/test/functional/interface_http.py b/test/functional/interface_http.py
--- a/test/functional/interface_http.py
+++ b/test/functional/interface_http.py
@@ -7,12 +7,12 @@
 # Test rpc http basics
 #
 
-from test_framework.test_framework import BitcoinTestFramework
-from test_framework.util import *
-
 import http.client
 import urllib.parse
 
+from test_framework.test_framework import BitcoinTestFramework
+from test_framework.util import assert_equal, str_to_b64str
+
 
 class HTTPBasicsTest (BitcoinTestFramework):
     def set_test_params(self):
diff --git a/test/functional/interface_rest.py b/test/functional/interface_rest.py
--- a/test/functional/interface_rest.py
+++ b/test/functional/interface_rest.py
@@ -7,16 +7,22 @@
 # Test REST interface
 #
 
-
-from test_framework.test_framework import BitcoinTestFramework
-from test_framework.util import *
-from struct import *
-from io import BytesIO
 from codecs import encode
-
+from decimal import Decimal
 import http.client
+from io import BytesIO
+import json
+from struct import pack, unpack
 import urllib.parse
 
+from test_framework.test_framework import BitcoinTestFramework
+from test_framework.util import (
+    assert_equal,
+    assert_greater_than,
+    connect_nodes_bi,
+    hex_str_to_bytes,
+)
+
 
 def deser_uint256(f):
     r = 0
diff --git a/test/functional/interface_zmq.py b/test/functional/interface_zmq.py
--- a/test/functional/interface_zmq.py
+++ b/test/functional/interface_zmq.py
@@ -8,10 +8,11 @@
 import struct
 
 from test_framework.test_framework import BitcoinTestFramework, SkipTest
-from test_framework.util import (assert_equal,
-                                 bytes_to_hex_str,
-                                 hash256,
-                                 )
+from test_framework.util import (
+    assert_equal,
+    bytes_to_hex_str,
+    hash256,
+)
 
 
 class ZMQTest (BitcoinTestFramework):