stats: Don't expect vec.front() to be predictable when populated from unordered container

test/common/stats/thread_local_store_test.cc

@@ -184,10 +184,10 @@ TEST_F(StatsThreadLocalStoreTest, NoTls) {
   store_->deliverHistogramToSinks(h1, 100);
 
   EXPECT_EQ(2UL, store_->counters().size());
-  EXPECT_EQ(&c1, store_->counters().front().get());
-  EXPECT_EQ(2L, store_->counters().front().use_count());
+  EXPECT_EQ(&c1, TestUtility::findCounter(*store_, "c1").get());
+  EXPECT_EQ(2L, TestUtility::findCounter(*store_, "c1").use_count());
   EXPECT_EQ(1UL, store_->gauges().size());
-  EXPECT_EQ(&g1, store_->gauges().front().get());
+  EXPECT_EQ(&g1, store_->gauges().front().get()); // front() ok when size()==1
   EXPECT_EQ(2L, store_->gauges().front().use_count());
 
   // Includes overflow stat.
@@ -212,20 +212,20 @@ TEST_F(StatsThreadLocalStoreTest, Tls) {
   EXPECT_EQ(&h1, &store_->histogram("h1"));
 
   EXPECT_EQ(2UL, store_->counters().size());
-  EXPECT_EQ(&c1, store_->counters().front().get());
-  EXPECT_EQ(3L, store_->counters().front().use_count());
+  EXPECT_EQ(&c1, TestUtility::findCounter(*store_, "c1").get());
+  EXPECT_EQ(3L, TestUtility::findCounter(*store_, "c1").use_count());
   EXPECT_EQ(1UL, store_->gauges().size());
-  EXPECT_EQ(&g1, store_->gauges().front().get());
+  EXPECT_EQ(&g1, store_->gauges().front().get()); // front() ok when size()==1
   EXPECT_EQ(3L, store_->gauges().front().use_count());
 
   store_->shutdownThreading();
   tls_.shutdownThread();
 
   EXPECT_EQ(2UL, store_->counters().size());
-  EXPECT_EQ(&c1, store_->counters().front().get());
-  EXPECT_EQ(2L, store_->counters().front().use_count());
+  EXPECT_EQ(&c1, TestUtility::findCounter(*store_, "c1").get());
+  EXPECT_EQ(2L, TestUtility::findCounter(*store_, "c1").use_count());
   EXPECT_EQ(1UL, store_->gauges().size());
-  EXPECT_EQ(&g1, store_->gauges().front().get());
+  EXPECT_EQ(&g1, store_->gauges().front().get()); // front() ok when size()==1
   EXPECT_EQ(2L, store_->gauges().front().use_count());
 
   // Includes overflow stat.
@@ -291,9 +291,9 @@ TEST_F(StatsThreadLocalStoreTest, ScopeDelete) {
   EXPECT_CALL(*alloc_, alloc(_));
   scope1->counter("c1");
   EXPECT_EQ(2UL, store_->counters().size());
-  CounterSharedPtr c1 = store_->counters().front();
+  CounterSharedPtr c1 = TestUtility::findCounter(*store_, "scope1.c1");
   EXPECT_EQ("scope1.c1", c1->name());
-  EXPECT_EQ(store_->source().cachedCounters().front(), c1);
+  EXPECT_EQ(TestUtility::findByName(store_->source().cachedCounters(), "scope1.c1"), c1);
 
   EXPECT_CALL(main_thread_dispatcher_, post(_));
   EXPECT_CALL(tls_, runOnAllThreads(_));

test/test_common/utility.cc

@@ -119,21 +119,11 @@ void TestUtility::feedBufferWithRandomCharacters(Buffer::Instance& buffer, uint6
 }
 
 Stats::CounterSharedPtr TestUtility::findCounter(Stats::Store& store, const std::string& name) {
-  for (auto counter : store.counters()) {
-    if (counter->name() == name) {
-      return counter;
-    }
-  }
-  return nullptr;
+  return findByName(store.counters(), name);
 }
 
 Stats::GaugeSharedPtr TestUtility::findGauge(Stats::Store& store, const std::string& name) {
-  for (auto gauge : store.gauges()) {
-    if (gauge->name() == name) {
-      return gauge;
-    }
-  }
-  return nullptr;
+  return findByName(store.gauges(), name);
 }
 
 std::list<Network::Address::InstanceConstSharedPtr>

test/test_common/utility.h

@@ -129,6 +129,21 @@ class TestUtility {
   static void feedBufferWithRandomCharacters(Buffer::Instance& buffer, uint64_t n_char,
                                              uint64_t seed = 0);
 
+  /**
+   * Finds a stat in a vector with the given name.
+   * @param name the stat name to look for.
+   * @param v the vector of stats.
+   * @return the stat
+   */
+  template <typename T> static T findByName(const std::vector<T>& v, const std::string& name) {
+    auto pos = std::find_if(v.begin(), v.end(),
+                            [&name](const T& stat) -> bool { return stat->name() == name; });
+    if (pos == v.end()) {
+      return nullptr;
+    }
+    return *pos;
+  }
+
   /**
    * Find a counter in a stats store.
    * @param store supplies the stats store.