Remove shutdown test from the unit tests and fix more comments

Author: anniefrchz

src/core/tsi/ssl_transport_security.cc

@@ -382,12 +382,9 @@ void TlsOffloadSignDoneCallback(
     result = async_result.first;
     next_args = std::move(async_result.second);
   }
-  if (next_args.has_value()) {
-    if (next_args->cb != nullptr) {
-      next_args->cb(result, next_args->user_data, next_args->bytes_to_send,
-                    next_args->bytes_to_send_size,
-                    next_args->handshaker_result);
-    }
+  if (next_args.has_value() && next_args->cb != nullptr) {
+    next_args->cb(result, next_args->user_data, next_args->bytes_to_send,
+                  next_args->bytes_to_send_size, next_args->handshaker_result);
   }
 }
 
@@ -434,9 +431,10 @@ enum ssl_private_key_result_t TlsPrivateKeySignWrapper(
   // Create the completion callback by binding the current context.
   auto done_callback =
       absl::bind_front(TlsOffloadSignDoneCallback, handshaker->Ref());
-  // Call the user's async sign function
-  // The contract with the user is that they MUST invoke the callback when
-  // complete in their implementation, and their impl MUST not block.
+  // Call the user's sign function. It can be sync or async.
+  // When the user's sign function is async, the contract is that they MUST
+  // invoke the callback when complete in their implementation, and their impl
+  // MUST not block.
   auto algorithm = ToSignatureAlgorithmClass(signature_algorithm);
   if (!algorithm.ok()) {
     handshaker->MaybeSetError(algorithm.status().ToString());
@@ -2915,6 +2913,8 @@ tsi_result tsi_create_ssl_client_handshaker_factory_with_options(
       grpc_core::Match(
           options->pem_key_cert_pair->private_key, [](const std::string&) {},
           [&](const std::shared_ptr<grpc_core::PrivateKeySigner>& key_signer) {
+            // The Handshaker Factory will own a shared copy of the reference
+            // passed through the options.
             impl->base.key_signer = key_signer;
           });
     }

test/core/tsi/private_key_offload_test.cc

@@ -540,21 +540,6 @@ TEST_P(PrivateKeyOffloadTest, OffloadFailsWithAsyncInvalidSignatureOnClient) {
       event_engine_.get());
 }
 
-// Verifies that client-side async signing is correctly cancelled when the
-// handshaker is shut down.
-TEST_P(PrivateKeyOffloadTest, OffloadFailsWithSignCancelledOnClient) {
-  auto signer = std::make_shared<AsyncTestPrivateKeySigner>(
-      "", event_engine_, AsyncTestPrivateKeySigner::Mode::kCancellation);
-  auto fixture = std::make_shared<SslOffloadTsiTestFixture>(
-      OffloadParty::kClient, std::static_pointer_cast<PrivateKeySigner>(signer),
-      GetParam());
-  event_engine_->RunAfter(std::chrono::seconds(1),
-                          [fixture]() { fixture->Shutdown(); });
-  fixture->Run(/*expect_success=*/false, /*expect_success_on_client*/ false,
-               event_engine_.get());
-  EXPECT_TRUE(signer->WasCancelled());
-}
-
 std::string TestNameSuffix(
     const ::testing::TestParamInfo<tsi_tls_version>& version) {
   if (version.param == tsi_tls_version::TSI_TLS1_2) return "TLS_1_2";

test/core/tsi/transport_security_test_lib.cc

@@ -388,9 +388,6 @@ static void do_handshaker_next(
         const_cast<const unsigned char**>(&bytes_to_send), &bytes_to_send_size,
         &handshaker_result, &on_handshake_next_done_wrapper, args);
     if (result != TSI_ASYNC) {
-      if (event_engine != nullptr) {
-        event_engine->TickUntilIdle();
-      }
       args->error = on_handshake_next_done(
           result, args, bytes_to_send, bytes_to_send_size, handshaker_result);
       if (!args->error.ok()) {
@@ -419,16 +416,10 @@ void tsi_test_do_handshake(
     client_args->transferred_data = false;
     server_args->transferred_data = false;
     do_handshaker_next(client_args, event_engine);
-    if (event_engine != nullptr) {
-      event_engine->TickUntilIdle();
-    }
     if (!client_args->error.ok()) {
       break;
     }
     do_handshaker_next(server_args, event_engine);
-    if (event_engine != nullptr) {
-      event_engine->TickUntilIdle();
-    }
     if (!server_args->error.ok()) {
       break;
     }