Unit tests

Author: cgilmour

test/CMakeLists.txt

@@ -22,6 +22,7 @@ add_executable(tests
     test_datadog_agent.cpp
     test_glob.cpp
     test_limiter.cpp
+    test_metrics.cpp
     test_msgpack.cpp
     test_parse_util.cpp
     test_smoke.cpp
@@ -30,6 +31,7 @@ add_executable(tests
     test_trace_id.cpp
     test_trace_segment.cpp
     test_tracer_config.cpp
+    test_tracer_telemetry.cpp
     test_tracer.cpp
     test_trace_sampler.cpp
 )

test/test_metrics.cpp

@@ -0,0 +1,35 @@
+// This test covers operations defined for metrics defined in `metrics.h`.
+
+#include <datadog/metrics.h>
+
+#include "test.h"
+
+using namespace datadog::tracing;
+
+TEST_CASE("Counter metrics") {
+  CounterMetric metric = {"test.counter.metric", {"testing-testing:123"}, true};
+
+  metric.inc();
+  metric.add(41);
+  REQUIRE(metric.value() == 42);
+  auto captured_value = metric.capture_and_reset_value();
+  REQUIRE(captured_value == 42);
+  REQUIRE(metric.value() == 0);
+}
+
+TEST_CASE("Gauge metrics") {
+  GaugeMetric metric = {"test.gauge.metric", {"testing-testing:123"}, true};
+
+  metric.inc();
+  metric.add(50);
+  metric.sub(8);
+  metric.dec();
+  REQUIRE(metric.value() == 42);
+  auto captured_value = metric.capture_and_reset_value();
+  REQUIRE(captured_value == 42);
+  REQUIRE(metric.value() == 0);
+
+  metric.add(10);
+  metric.sub(11);
+  REQUIRE(metric.value() == 0);
+}

test/test_tracer_telemetry.cpp

@@ -0,0 +1,79 @@
+// These are tests for `TracerTelemetry`. TracerTelemetry is used to measure
+// activity in other parts of the tracer implementation, and construct messages
+// that are sent to the datadog agent.
+
+#include <datadog/span_defaults.h>
+#include <datadog/tracer_telemetry.h>
+
+#include <datadog/json.hpp>
+
+#include "mocks/loggers.h"
+#include "test.h"
+
+using namespace datadog::tracing;
+
+TEST_CASE("Tracer telemetry") {
+  const std::time_t mock_time = 1672484400;
+  const Clock clock = [mock_time]() {
+    TimePoint result;
+    result.wall = std::chrono::system_clock::from_time_t(mock_time);
+    return result;
+  };
+  auto logger = std::make_shared<MockLogger>();
+  auto span_defaults = std::make_shared<SpanDefaults>();
+  span_defaults->service = "testsvc";
+  span_defaults->environment = "test";
+  TracerTelemetry tracer_telemetry = {true, clock, logger, span_defaults};
+
+  SECTION("generates app-started message") {
+    auto app_started_message =
+        tracer_telemetry.app_started(nlohmann::json::object());
+    auto app_started = nlohmann::json::parse(app_started_message);
+    REQUIRE(app_started["request_type"] == "app-started");
+  }
+
+  SECTION("generates a heartbeat message") {
+    auto heartbeat_message = tracer_telemetry.heartbeat_and_telemetry();
+    auto message_batch = nlohmann::json::parse(heartbeat_message);
+    REQUIRE(message_batch["payload"].size() == 1);
+    auto heartbeat = message_batch["payload"][0];
+    REQUIRE(heartbeat["request_type"] == "app-heartbeat");
+  }
+
+  SECTION("captures metrics and sends generate-metrics payload") {
+    tracer_telemetry.metrics().tracer.trace_segments_created_new.inc();
+    REQUIRE(
+        tracer_telemetry.metrics().tracer.trace_segments_created_new.value() ==
+        1);
+    tracer_telemetry.capture_metrics();
+    REQUIRE(
+        tracer_telemetry.metrics().tracer.trace_segments_created_new.value() ==
+        0);
+    auto heartbeat_and_telemetry_message =
+        tracer_telemetry.heartbeat_and_telemetry();
+    auto message_batch = nlohmann::json::parse(heartbeat_and_telemetry_message);
+    REQUIRE(message_batch["payload"].size() == 2);
+    auto generate_metrics = message_batch["payload"][1];
+    REQUIRE(generate_metrics["request_type"] == "generate-metrics");
+    auto payload = generate_metrics["payload"];
+    auto series = payload["series"];
+    REQUIRE(series.size() == 1);
+    auto metric = series[0];
+    REQUIRE(metric["metric"] == "trace_segments_created");
+    auto tags = metric["tags"];
+    REQUIRE(tags.size() == 1);
+    REQUIRE(tags[0] == "new_continued:new");
+    auto points = metric["points"];
+    REQUIRE(points.size() == 1);
+    REQUIRE(points[0][0] == mock_time);
+    REQUIRE(points[0][1] == 1);
+  }
+
+  SECTION("generates an app-closing event") {
+    auto app_closing_message = tracer_telemetry.app_closing();
+    auto message_batch = nlohmann::json::parse(app_closing_message);
+    REQUIRE(message_batch["payload"].size() == 1);
+    auto heartbeat = message_batch["payload"][0];
+    REQUIRE(heartbeat["request_type"] == "app-closing");
+  }
+}