CPP-935: Fix latency-aware policy (#502)

Latency-aware policy update timer wasn't started on request processors.

src/latency_aware_policy.cpp

@@ -102,6 +102,8 @@ Host::Ptr LatencyAwarePolicy::LatencyAwareQueryPlan::compute_next() {
       return host;
     }
 
+    LOG_TRACE("Skipping %s because latency is too high %f", host->address_string().c_str(),
+              static_cast<double>(latency.average) / 1e6);
     skipped_.push_back(host);
   }
 

src/request_processor.cpp

@@ -214,6 +214,7 @@ RequestProcessor::RequestProcessor(RequestProcessorListener* listener, EventLoop
   for (LoadBalancingPolicy::Vec::const_iterator it = policies.begin(); it != policies.end(); ++it) {
     // Initialize the load balancing policies
     (*it)->init(connected_host, hosts, random, local_dc);
+    (*it)->register_handles(event_loop_->loop());
   }
 
   listener_->on_connect(this);
@@ -308,6 +309,10 @@ void RequestProcessor::on_requires_flush() {
 }
 
 void RequestProcessor::on_close(ConnectionPoolManager* manager) {
+  for (LoadBalancingPolicy::Vec::const_iterator it = load_balancing_policies_.begin();
+       it != load_balancing_policies_.end(); ++it) {
+    (*it)->close_handles();
+  }
   async_.close_handle();
   prepare_.close_handle();
   timer_.stop();

tests/src/integration/tests/test_latency_aware_policy.cpp

@@ -0,0 +1,59 @@
+/*
+  Copyright (c) DataStax, Inc.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+  http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+*/
+
+#include "cassandra.h"
+#include "integration.hpp"
+
+#include <algorithm>
+#include <iterator>
+
+class LatencyAwarePolicyTest : public Integration {
+public:
+  void SetUp() {
+    number_dc1_nodes_ = 3;
+    is_session_requested_ = false;
+    Integration::SetUp();
+  }
+};
+
+/**
+ * Validates that latency-aware policy is enabled and updating the minimum average latency.
+ *
+ * @since 2.16.1
+ * @jira_ticket CPP-935
+ * @test_category load_balancing_policy:latency_aware
+ */
+CASSANDRA_INTEGRATION_TEST_F(LatencyAwarePolicyTest, IsEnabled) {
+  CHECK_FAILURE
+  cluster_ = default_cluster();
+  cluster_.with_load_balance_round_robin();
+  cass_cluster_set_token_aware_routing(cluster_.get(), cass_false);
+  cass_cluster_set_latency_aware_routing(cluster_.get(), cass_true);
+  cass_cluster_set_latency_aware_routing_settings(cluster_.get(), 2.0, 100LL * 1000LL * 1000LL,
+                                                  10LL * 1000LL * 1000LL * 1000LL, 100, 1);
+  connect(cluster_);
+
+  logger_.reset();
+  logger_.add_critera("Calculated new minimum:");
+
+  for (int i = 0; i < 9; ++i) { // Greater than min measured
+    session_.execute("SELECT release_version FROM system.local");
+  }
+
+  msleep(250);
+
+  EXPECT_GT(logger_.count(), 0u);
+}