Change Stackdriver units to "1" for count views. (#134)

Author: Ian Sturdy

opencensus/exporters/stats/stackdriver/internal/stackdriver_utils.cc

@@ -160,7 +160,10 @@ void SetMetricDescriptor(
   }
   metric_descriptor->set_metric_kind(google::api::MetricDescriptor::CUMULATIVE);
   metric_descriptor->set_value_type(GetValueType(view_descriptor));
-  metric_descriptor->set_unit(view_descriptor.measure_descriptor().units());
+  metric_descriptor->set_unit(
+      view_descriptor.aggregation() == opencensus::stats::Aggregation::Count()
+          ? "1"
+          : view_descriptor.measure_descriptor().units());
   metric_descriptor->set_description(view_descriptor.description());
 }
 

opencensus/exporters/stats/stackdriver/internal/stackdriver_utils_test.cc

@@ -133,6 +133,18 @@ TEST(StackdriverUtilsTest, SetMetricDescriptorUnits) {
   EXPECT_EQ(units, metric_descriptor.unit());
 }
 
+TEST(StackdriverUtilsTest, SetMetricDescriptorUnitsCount) {
+  opencensus::stats::MeasureDouble::Register("measure", "", "test_units");
+  const auto view_descriptor =
+      opencensus::stats::ViewDescriptor()
+          .set_measure("measure")
+          .set_aggregation(opencensus::stats::Aggregation::Count());
+  google::api::MetricDescriptor metric_descriptor;
+  SetMetricDescriptor("", view_descriptor, &metric_descriptor);
+
+  EXPECT_EQ("1", metric_descriptor.unit());
+}
+
 TEST(StackdriverUtilsTest, SetMetricDescriptorDescription) {
   const std::string description = "test description";
   const auto view_descriptor =