[CODE HEALTH] Fix clang-tidy narrowing-conversions warnings in tests

Apply static_cast at the narrowing site in three test files:

- otlp_metrics_serialization_test.cc: cast loop index when calling
  protobuf data_points(int) accessors (3 sites).
- aggregation_test.cc: cast size_t max_buckets_ on ternary branches
  where the lvalue is declared int (2 sites).
- metric_test_stress.cc: cast hardware_concurrency() result and the
  uint64_t bucket counts/totals used for int64_t accumulation (3 sites).

Decrement clang-tidy warning limits by 8 to match the removed unique
warnings.

Fixes #3978

Signed-off-by: Mateen Anjum <mateenali66@gmail.com>

Author: mateenali66

.github/workflows/clang-tidy.yaml

@@ -17,9 +17,9 @@ jobs:
       matrix:
         include:
           - cmake_options: all-options-abiv1-preview
-            warning_limit: 57
+            warning_limit: 49
           - cmake_options: all-options-abiv2-preview
-            warning_limit: 59
+            warning_limit: 51
     env:
       CC: /usr/bin/clang-18
       CXX: /usr/bin/clang++-18

CHANGELOG.md

@@ -37,6 +37,9 @@ Increment the:
 * [CODE HEALTH] Cleanup nostd variant access in API and SDK
   [#3965](https://github.com/open-telemetry/opentelemetry-cpp/pull/3965)
 
+* [CODE HEALTH] Fix clang-tidy narrowing-conversions warnings in tests
+  [#3978](https://github.com/open-telemetry/opentelemetry-cpp/issues/3978)
+
 * Enable WITH_OTLP_RETRY_PREVIEW by default
   [#3953](https://github.com/open-telemetry/opentelemetry-cpp/pull/3953)
 

exporters/otlp/test/otlp_metrics_serialization_test.cc

@@ -278,7 +278,7 @@ TEST(OtlpMetricSerializationTest, Counter)
   EXPECT_EQ(sum.is_monotonic(), true);
   for (size_t i = 0; i < 1; i++)
   {
-    const auto &proto_number_point = sum.data_points(i);
+    const auto &proto_number_point = sum.data_points(static_cast<int>(i));
     EXPECT_EQ(proto_number_point.as_double(), i == 0 ? 10.2 : 20.2);
   }
 
@@ -308,7 +308,7 @@ TEST(OtlpMetricSerializationTest, Histogram)
             proto::metrics::v1::AggregationTemporality::AGGREGATION_TEMPORALITY_CUMULATIVE);
   for (size_t i = 0; i < 1; i++)
   {
-    const auto &proto_number_point = histogram.data_points(i);
+    const auto &proto_number_point = histogram.data_points(static_cast<int>(i));
     EXPECT_EQ(proto_number_point.sum(), i == 0 ? 100.2 : 200.2);
   }
 
@@ -381,7 +381,7 @@ TEST(OtlpMetricSerializationTest, ObservableGauge)
   otlp_exporter::OtlpMetricUtils::ConvertGaugeMetric(data, &gauge);
   for (size_t i = 0; i < 1; i++)
   {
-    const auto &proto_number_point = gauge.data_points(i);
+    const auto &proto_number_point = gauge.data_points(static_cast<int>(i));
     EXPECT_EQ(proto_number_point.as_double(), i == 0 ? 30.2 : 50.2);
   }
 

sdk/test/metrics/aggregation_test.cc

@@ -416,8 +416,8 @@ TEST(Aggregation, Base2ExponentialHistogramAggregationMerge)
     const int expected_scale =
         aggr_point.scale_ < default_point.scale_ ? aggr_point.scale_ : default_point.scale_;
     const int expected_max_buckets = aggr_point.max_buckets_ < default_point.max_buckets_
-                                         ? aggr_point.max_buckets_
-                                         : default_point.max_buckets_;
+                                         ? static_cast<int>(aggr_point.max_buckets_)
+                                         : static_cast<int>(default_point.max_buckets_);
     const int expected_zero_count  = 0;
 
     auto merged_from_default = aggr.Merge(*default_aggr);
@@ -438,8 +438,8 @@ TEST(Aggregation, Base2ExponentialHistogramAggregationMerge)
     const int expected_scale =
         aggr_point.scale_ < zero_point.scale_ ? aggr_point.scale_ : zero_point.scale_;
     const int expected_max_buckets = aggr_point.max_buckets_ < zero_point.max_buckets_
-                                         ? aggr_point.max_buckets_
-                                         : zero_point.max_buckets_;
+                                         ? static_cast<int>(aggr_point.max_buckets_)
+                                         : static_cast<int>(zero_point.max_buckets_);
     const int expected_zero_count  = 1;
 
     auto merged_from_zero = aggr.Merge(zero_aggr);

sdk/test/metrics/metric_test_stress.cc

@@ -95,7 +95,7 @@ TEST(HistogramStress, UnsignedInt64)
   //
   // Start logging threads
   //
-  int record_thread_count = std::thread::hardware_concurrency() - 1;
+  int record_thread_count = static_cast<int>(std::thread::hardware_concurrency()) - 1;
   if (record_thread_count <= 0)
   {
     record_thread_count = 1;
@@ -160,12 +160,12 @@ TEST(HistogramStress, UnsignedInt64)
     int64_t collected_bucket_sum = 0;
     for (const auto &count : actual.counts_)
     {
-      collected_bucket_sum += count;
+      collected_bucket_sum += static_cast<int64_t>(count);
     }
     ASSERT_EQ(collected_bucket_sum, actual.count_);
 
     collected_sum += opentelemetry::nostd::get<int64_t>(actual.sum_);
-    collected_count += actual.count_;
+    collected_count += static_cast<int64_t>(actual.count_);
   }
 
   ASSERT_EQ(expected_count, collected_count);