diff --git a/tools/testing/selftests/tc-testing/tdc.py b/tools/testing/selftests/tc-testing/tdc.py
index 6c220bc26d9f..7b50775abaf6 100755
--- a/tools/testing/selftests/tc-testing/tdc.py
+++ b/tools/testing/selftests/tc-testing/tdc.py
@@ -445,7 +445,7 @@ def generate_case_ids(alltests):
     for c in alltests:
         if (c["id"] == ""):
             while True:
-                newid = str('%04x' % random.randrange(16**4))
+                newid = str('{:04x}'.format(random.randrange(16**4)))
                 if (does_id_exist(alltests, newid)):
                     continue
                 else:
diff --git a/tools/testing/selftests/tc-testing/tdc_batch.py b/tools/testing/selftests/tc-testing/tdc_batch.py
index 707c6bfef689..52fa539dc662 100755
--- a/tools/testing/selftests/tc-testing/tdc_batch.py
+++ b/tools/testing/selftests/tc-testing/tdc_batch.py
@@ -49,13 +49,13 @@ index = 0
 for i in range(0x100):
     for j in range(0x100):
         for k in range(0x100):
-            mac = ("%02x:%02x:%02x" % (i, j, k))
+            mac = ("{:02x}:{:02x}:{:02x}".format(i, j, k))
             src_mac = "e4:11:00:" + mac
             dst_mac = "e4:12:00:" + mac
-            cmd = ("filter add dev %s %s protocol ip parent ffff: flower %s "
-                   "src_mac %s dst_mac %s action drop %s" %
+            cmd = ("filter add dev {} {} protocol ip parent ffff: flower {} "
+                   "src_mac {} dst_mac {} action drop {}".format
                    (device, prio, skip, src_mac, dst_mac, share_action))
-            file.write("%s\n" % cmd)
+            file.write("{}\n".format(cmd))
             index += 1
             if index >= number:
                 file.close()