Fix test

test/core/end2end/tests/bad_ping.cc

@@ -155,14 +155,15 @@ static void test_bad_ping(grpc_end2end_test_config config) {
   cq_verify(cqv);
 
   // Send too many pings to the server to trigger the punishment:
-  // Each ping will trigger a ping strike, and we need at least MAX_PING_STRIKES
-  // strikes to trigger the punishment. So (MAX_PING_STRIKES + 1) pings are
+  // The first ping will let server mark its last_recv time. Afterwards, each
+  // ping will trigger a ping strike, and we need at least MAX_PING_STRIKES
+  // strikes to trigger the punishment. So (MAX_PING_STRIKES + 2) pings are
   // needed here.
   int i;
-  for (i = 1; i <= MAX_PING_STRIKES + 1; i++) {
+  for (i = 1; i <= MAX_PING_STRIKES + 2; i++) {
     grpc_channel_ping(f.client, f.cq, tag(200 + i), nullptr);
     CQ_EXPECT_COMPLETION(cqv, tag(200 + i), 1);
-    if (i == MAX_PING_STRIKES + 1) {
+    if (i == MAX_PING_STRIKES + 2) {
       CQ_EXPECT_COMPLETION(cqv, tag(1), 1);
     }
     cq_verify(cqv);