This test is requested by Stephen and Jakub during review,
it is for validating backlog.

Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
---
 .../tc-testing/tc-tests/infra/qdiscs.json     | 33 +++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/tools/testing/selftests/tc-testing/tc-tests/infra/qdiscs.json b/tools/testing/selftests/tc-testing/tc-tests/infra/qdiscs.json
index 4ebdb27e39b3..83ff9e7406f2 100644
--- a/tools/testing/selftests/tc-testing/tc-tests/infra/qdiscs.json
+++ b/tools/testing/selftests/tc-testing/tc-tests/infra/qdiscs.json
@@ -988,6 +988,39 @@
             "$TC qdisc del dev $DUMMY root handle 1: prio"
         ]
     },
+    {
+        "id": "3c5d",
+        "name": "Test HTB with NETEM duplication Backlog Accounting",
+        "category": [
+            "qdisc",
+            "htb",
+            "netem"
+        ],
+        "plugins": {
+            "requires": [
+                "nsPlugin"
+            ]
+        },
+        "setup": [
+            "$IP link set dev $DUMMY up || true",
+            "$IP addr add 10.10.11.10/24 dev $DUMMY || true",
+            "$TC qdisc add dev $DUMMY root handle 1: htb default 1",
+            "$TC class add dev $DUMMY parent 1: classid 1:1 htb rate 100mbit",
+            "$TC qdisc add dev $DUMMY parent 1:1 handle 10: netem limit 4 duplicate 100%",
+            [
+                "ping -c1 -W0.01 -I $DUMMY 10.10.11.11",
+                1
+            ]
+        ],
+        "cmdUnderTest": "$TC qdisc del dev $DUMMY handle 10: parent 1:1",
+        "expExitCode": "0",
+        "verifyCmd": "$TC -s qdisc show dev $DUMMY",
+        "matchPattern": "backlog 0b 0p",
+        "matchCount": "1",
+        "teardown": [
+            "$TC qdisc del dev $DUMMY root handle 1: htb"
+        ]
+    },
     {
         "id": "4989",
         "name": "Try to add an fq child to an ingress qdisc",
-- 
2.34.1