Minor test improvements

Signed-off-by: Devin Bonnie <dbbonnie@amazon.com>

system_metrics_collector/test/system_metrics_collector/test_functions.hpp

@@ -103,7 +103,6 @@ void ExpectedStatisticEquals(
   }
 }
 
-
 /**
  * Provide an interface to wait for a promise to be satisfied via its future.
  */

system_metrics_collector/test/system_metrics_collector/test_linux_cpu_measurement.cpp

@@ -52,8 +52,10 @@ using test_constants::kProcSamples;
 
 namespace
 {
-constexpr const char kTestNodeName[] = "test_measure_linux_cpu";
+constexpr const char kTestCpuNodeName[] = "test_measure_linux_cpu";
 constexpr const char kTestMetricName[] = "system_cpu_percent_used";
+constexpr const std::chrono::milliseconds kMeasurePeriod{50};
+constexpr const std::chrono::milliseconds kPublishPeriod{6 * 50};
 }  // namespace
 
 /**
@@ -101,13 +103,13 @@ class LinuxCpuMeasurementTestFixture : public ::testing::Test
     rclcpp::NodeOptions options;
     options.append_parameter_override(
       system_metrics_collector::collector_node_constants::kCollectPeriodParam,
-      test_constants::kMeasurePeriod.count());
+      kMeasurePeriod.count());
     options.append_parameter_override(
       system_metrics_collector::collector_node_constants::kPublishPeriodParam,
-      test_constants::kPublishPeriod.count());
+      kPublishPeriod.count());
 
     test_measure_linux_cpu_ = std::make_shared<TestLinuxCpuMeasurementNode>(
-      kTestNodeName, options);
+      kTestCpuNodeName, options);
 
     ASSERT_FALSE(test_measure_linux_cpu_->IsStarted());
 
@@ -207,7 +209,7 @@ TEST_F(LinuxCpuMeasurementTestFixture, TestPeriodicMeasurement)
   EXPECT_TRUE(std::isnan(data.standard_deviation));
   EXPECT_EQ(0, data.sample_count);
 
-// reactivate the node
+  // reactivate the node
   test_measure_linux_cpu_->activate();
   ASSERT_EQ(State::PRIMARY_STATE_ACTIVE, test_measure_linux_cpu_->get_current_state().id());
 
@@ -267,11 +269,10 @@ TEST_F(LinuxCpuMeasurementTestFixture, TestPublishMessage)
   ex.spin_until_future_complete(
     test_receive_measurements->GetFuture(), test_constants::kPublishTestTimeout);
 
-  // generate expected data: expectation is that 2 samples are taken within the publish
-  // time frame. (kProcSamples[0], kProcSamples[1])
-  // (kProcSamples[1], kProcSamples[2])
+  // generate expected data: expectation is that 6 samples are taken within the publish
+  // time frame
   MovingAverageStatistics expected_moving_average;
-  for (int i = 0; i <= 1; i++) {
+  for (int i = 0; i < kProcSamples.size() - 1; i++) {
     const auto d = ComputeCpuActivePercentage(
       ProcessStatCpuLine(kProcSamples[i]),
       ProcessStatCpuLine(kProcSamples[i + 1]));
@@ -284,7 +285,7 @@ TEST_F(LinuxCpuMeasurementTestFixture, TestPublishMessage)
   // check expected received message
   const auto received_message = test_receive_measurements->GetLastReceivedMessage();
 
-  EXPECT_EQ(kTestNodeName, received_message.measurement_source_name);
+  EXPECT_EQ(kTestCpuNodeName, received_message.measurement_source_name);
   EXPECT_EQ(kTestMetricName, received_message.metrics_source);
   EXPECT_EQ(
     system_metrics_collector::collector_node_constants::kPercentUnitName,

system_metrics_collector/test/system_metrics_collector/test_linux_memory_measurement.cpp

@@ -53,7 +53,7 @@ using moving_average_statistics::StatisticData;
 
 namespace
 {
-constexpr const char kTestNodeName[] = "test_measure_linux_memory";
+constexpr const char kTestMemoryNodeName[] = "test_measure_linux_memory";
 constexpr const char kTestMetricName[] = "system_memory_percent_used";
 
 const std::vector<std::string> kSamples = {
@@ -131,7 +131,7 @@ class LinuxMemoryMeasurementTestFixture : public ::testing::Test
       test_constants::kPublishPeriod.count());
 
     test_measure_linux_memory_ = std::make_shared<TestLinuxMemoryMeasurementNode>(
-      kTestNodeName, options);
+      kTestMemoryNodeName, options);
 
     ASSERT_FALSE(test_measure_linux_memory_->IsStarted());
 
@@ -291,7 +291,8 @@ TEST_F(LinuxMemoryMeasurementTestFixture, TestPublishMessage)
   ex.spin_until_future_complete(
     test_receive_measurements->GetFuture(), test_constants::kPublishTestTimeout);
 
-  // generate expected data
+  // generate expected data, expectation is that all of kSamples was measured
+  // before the message was published
   MovingAverageStatistics expected_moving_average;
   for (const std::string & sample : kSamples) {
     const auto d = ProcessMemInfoLines(sample);
@@ -304,7 +305,7 @@ TEST_F(LinuxMemoryMeasurementTestFixture, TestPublishMessage)
   // check expected received message
   const auto received_message = test_receive_measurements->GetLastReceivedMessage();
 
-  EXPECT_EQ(kTestNodeName, received_message.measurement_source_name);
+  EXPECT_EQ(kTestMemoryNodeName, received_message.measurement_source_name);
   EXPECT_EQ(kTestMetricName, received_message.metrics_source);
   EXPECT_EQ(
     system_metrics_collector::collector_node_constants::kPercentUnitName,