selftests: tc-testing: Add testcases to test new flush behaviour

Add tdc test cases to verify new flush behaviour is correct, which do
the following:

- Try to flush only one action which is being referenced by a filter
- Try to flush three actions where the last one (index 3) is being
  referenced by a filter
Signed-off-by: Victor Nogueira <victor@mojatatu.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools/testing/selftests/tc-testing/tc-tests/actions/gact.json

@@ -609,5 +609,82 @@
         "teardown": [
             "$TC actions flush action gact"
         ]
+    },
+    {
+        "id": "7f52",
+        "name": "Try to flush action which is referenced by filter",
+        "category": [
+            "actions",
+            "gact"
+        ],
+        "plugins": {
+            "requires": "nsPlugin"
+        },
+        "setup": [
+            [
+                "$TC actions flush action gact",
+                0,
+                1,
+                255
+            ],
+            "$TC qdisc add dev $DEV1 ingress",
+            "$TC actions add action pass index 1",
+            "$TC filter add dev $DEV1 protocol all ingress prio 1 handle 0x1234 matchall action gact index 1"
+        ],
+        "cmdUnderTest": "$TC actions flush action gact",
+        "expExitCode": "1",
+        "verifyCmd": "$TC actions ls action gact",
+        "matchPattern": "total acts 1.*action order [0-9]*: gact action pass.*index 1 ref 2 bind 1",
+        "matchCount": "1",
+        "teardown": [
+            "$TC qdisc del dev $DEV1 ingress",
+            [
+                "sleep 1; $TC actions flush action gact",
+                0,
+                1
+            ]
+        ]
+    },
+    {
+        "id": "ae1e",
+        "name": "Try to flush actions when last one is referenced by filter",
+        "category": [
+            "actions",
+            "gact"
+        ],
+        "plugins": {
+            "requires": "nsPlugin"
+        },
+        "setup": [
+            [
+                "$TC actions flush action gact",
+                0,
+                1,
+                255
+            ],
+            "$TC qdisc add dev $DEV1 ingress",
+	    [
+                "$TC actions add action pass index 1",
+		0,
+		1,
+		255
+	    ],
+            "$TC actions add action reclassify index 2",
+            "$TC actions add action drop index 3",
+            "$TC filter add dev $DEV1 protocol all ingress prio 1 handle 0x1234 matchall action gact index 3"
+        ],
+        "cmdUnderTest": "$TC actions flush action gact",
+        "expExitCode": "0",
+        "verifyCmd": "$TC actions ls action gact",
+        "matchPattern": "total acts 1.*action order [0-9]*: gact action drop.*index 3 ref 2 bind 1",
+        "matchCount": "1",
+        "teardown": [
+            "$TC qdisc del dev $DEV1 ingress",
+            [
+                "sleep 1; $TC actions flush action gact",
+                0,
+                1
+            ]
+        ]
     }
 ]