selftests/tc-testing: add selftests for multiq qdisc

Test 20ba: Add multiq Qdisc to multi-queue device (8 queues)
Test 4301: List multiq Class
Test 7832: Delete nonexistent multiq Qdisc
Test 2891: Delete multiq Qdisc twice
Test 1329: Add multiq Qdisc to single-queue device
Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>
Reviewed-by: Victor Nogueira <victor@mojatatu.com>
Tested-by: Victor Nogueira <victor@mojatatu.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools/testing/selftests/tc-testing/tc-tests/qdiscs/multiq.json

+[
+    {
+        "id": "20ba",
+        "name": "Add multiq Qdisc to multi-queue device (8 queues)",
+        "category": [
+            "qdisc",
+            "multiq"
+        ],
+        "plugins": {
+            "requires": "nsPlugin"
+        },
+        "setup": [
+            "echo \"1 1 8\" > /sys/bus/netdevsim/new_device"
+        ],
+        "cmdUnderTest": "$TC qdisc add dev $ETH root handle 1: multiq",
+        "expExitCode": "0",
+        "verifyCmd": "$TC qdisc show dev $ETH",
+        "matchPattern": "qdisc multiq 1: root refcnt [0-9]+ bands 8",
+        "matchCount": "1",
+        "teardown": [
+            "echo \"1\" > /sys/bus/netdevsim/del_device"
+        ]
+    },
+    {
+        "id": "4301",
+        "name": "List multiq Class",
+        "category": [
+            "qdisc",
+            "multiq"
+        ],
+        "plugins": {
+            "requires": "nsPlugin"
+        },
+        "setup": [
+            "echo \"1 1 8\" > /sys/bus/netdevsim/new_device"
+        ],
+        "cmdUnderTest": "$TC qdisc add dev $ETH root handle 1: multiq",
+        "expExitCode": "0",
+        "verifyCmd": "$TC class show dev $ETH",
+        "matchPattern": "class multiq 1:[0-9]+ parent 1:",
+        "matchCount": "8",
+        "teardown": [
+            "echo \"1\" > /sys/bus/netdevsim/del_device"
+        ]
+    },
+    {
+        "id": "7832",
+        "name": "Delete nonexistent multiq Qdisc",
+        "category": [
+            "qdisc",
+            "multiq"
+        ],
+        "plugins": {
+            "requires": "nsPlugin"
+        },
+        "setup": [
+            "echo \"1 1 4\" > /sys/bus/netdevsim/new_device"
+        ],
+        "cmdUnderTest": "$TC qdisc del dev $ETH root handle 1: multiq",
+        "expExitCode": "2",
+        "verifyCmd": "$TC qdisc show dev $ETH",
+        "matchPattern": "qdisc multiq 1: root",
+        "matchCount": "0",
+        "teardown": [
+            "echo \"1\" > /sys/bus/netdevsim/del_device"
+        ]
+    },
+    {
+        "id": "2891",
+        "name": "Delete multiq Qdisc twice",
+        "category": [
+            "qdisc",
+            "multiq"
+        ],
+        "plugins": {
+            "requires": "nsPlugin"
+        },
+        "setup": [
+            "echo \"1 1 8\" > /sys/bus/netdevsim/new_device",
+            "$TC qdisc add dev $ETH root handle 1: multiq",
+            "$TC qdisc del dev $ETH root handle 1:"
+        ],
+        "cmdUnderTest": "$TC qdisc del dev $ETH root handle 1:",
+        "expExitCode": "2",
+        "verifyCmd": "$TC qdisc show dev $ETH",
+        "matchPattern": "qdisc mqprio 1: root",
+        "matchCount": "0",
+        "teardown": [
+            "echo \"1\" > /sys/bus/netdevsim/del_device"
+        ]
+    },
+    {
+        "id": "1329",
+        "name": "Add multiq Qdisc to single-queue device",
+        "category": [
+            "qdisc",
+            "multiq"
+        ],
+        "plugins": {
+            "requires": "nsPlugin"
+        },
+        "setup": [
+            "echo \"1 1\" > /sys/bus/netdevsim/new_device"
+        ],
+        "cmdUnderTest": "$TC qdisc add dev $ETH root handle 1: multiq",
+        "expExitCode": "2",
+        "verifyCmd": "$TC qdisc show dev $ETH",
+        "matchPattern": "qdisc multiq 1: root",
+        "matchCount": "0",
+        "teardown": [
+            "echo \"1\" > /sys/bus/netdevsim/del_device"
+        ]
+    }
+]