1 files changed, 173 insertions, 0 deletions
diff --git a/toolkit/components/telemetry/tests/gtest/TestCounters.cpp b/toolkit/components/telemetry/tests/gtest/TestCounters.cpp
new file mode 100644
index 0000000000..2950500c3f
--- /dev/null
+++ b/toolkit/components/telemetry/tests/gtest/TestCounters.cpp
@@ -0,0 +1,173 @@
+/* vim:set ts=2 sw=2 sts=0 et: */
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+#include "gtest/gtest.h"
+#include "js/Conversions.h"
+#include "mozilla/Telemetry.h"
+#include "TelemetryFixture.h"
+#include "TelemetryTestHelpers.h"
+
+using namespace mozilla;
+using namespace TelemetryTestHelpers;
+
+TEST_F(TelemetryTestFixture, AutoCounter) {
+  const uint32_t kExpectedValue = 100;
+  AutoJSContextWithGlobal cx(mCleanGlobal);
+
+  const char* telemetryTestCountName =
+      Telemetry::GetHistogramName(Telemetry::TELEMETRY_TEST_COUNT);
+
+  GetAndClearHistogram(cx.GetJSContext(), mTelemetry, "TELEMETRY_TEST_COUNT"_ns,
+                       false);
+
+  // Accumulate in the histogram
+  {
+    Telemetry::AutoCounter<Telemetry::TELEMETRY_TEST_COUNT> autoCounter;
+    autoCounter += kExpectedValue / 2;
+  }
+  // This counter should not accumulate since it does not go out of scope
+  Telemetry::AutoCounter<Telemetry::TELEMETRY_TEST_COUNT> autoCounter;
+  autoCounter += kExpectedValue;
+  // Accumulate a second time in the histogram
+  {
+    Telemetry::AutoCounter<Telemetry::TELEMETRY_TEST_COUNT> autoCounter;
+    autoCounter += kExpectedValue / 2;
+  }
+
+  // Get a snapshot for all the histograms
+  JS::RootedValue snapshot(cx.GetJSContext());
+  GetSnapshots(cx.GetJSContext(), mTelemetry, telemetryTestCountName, &snapshot,
+               false);
+
+  // Get the histogram from the snapshot
+  JS::RootedValue histogram(cx.GetJSContext());
+  GetProperty(cx.GetJSContext(), telemetryTestCountName, snapshot, &histogram);
+
+  // Get "sum" property from histogram
+  JS::RootedValue sum(cx.GetJSContext());
+  GetProperty(cx.GetJSContext(), "sum", histogram, &sum);
+
+  // Check that the "sum" stored in the histogram matches with |kExpectedValue|
+  uint32_t uSum = 0;
+  JS::ToUint32(cx.GetJSContext(), sum, &uSum);
+  ASSERT_EQ(uSum, kExpectedValue)
+      << "The histogram is not returning expected value";
+}
+
+TEST_F(TelemetryTestFixture, AutoCounterUnderflow) {
+  const uint32_t kExpectedValue = 0;
+  AutoJSContextWithGlobal cx(mCleanGlobal);
+
+  const char* telemetryTestCountName =
+      Telemetry::GetHistogramName(Telemetry::TELEMETRY_TEST_COUNT);
+
+  GetAndClearHistogram(cx.GetJSContext(), mTelemetry, "TELEMETRY_TEST_COUNT"_ns,
+                       false);
+
+  // Accumulate in the histogram
+  {
+    Telemetry::AutoCounter<Telemetry::TELEMETRY_TEST_COUNT> autoCounter;
+    autoCounter += -1;
+  }
+
+  // Get a snapshot for all the histograms
+  JS::RootedValue snapshot(cx.GetJSContext());
+  GetSnapshots(cx.GetJSContext(), mTelemetry, telemetryTestCountName, &snapshot,
+               false);
+
+  // Get the histogram from the snapshot
+  JS::RootedValue histogram(cx.GetJSContext());
+  GetProperty(cx.GetJSContext(), telemetryTestCountName, snapshot, &histogram);
+
+  // Get "sum" property from histogram
+  JS::RootedValue sum(cx.GetJSContext());
+  GetProperty(cx.GetJSContext(), "sum", histogram, &sum);
+
+  // Check that the "sum" stored in the histogram matches with |kExpectedValue|
+  uint32_t uSum = 42;
+  JS::ToUint32(cx.GetJSContext(), sum, &uSum);
+  ASSERT_EQ(uSum, kExpectedValue)
+      << "The histogram is supposed to return 0 when an underflow occurs.";
+}
+
+TEST_F(TelemetryTestFixture, RuntimeAutoCounter) {
+  const uint32_t kExpectedValue = 100;
+  AutoJSContextWithGlobal cx(mCleanGlobal);
+
+  const char* telemetryTestCountName =
+      Telemetry::GetHistogramName(Telemetry::TELEMETRY_TEST_COUNT);
+
+  GetAndClearHistogram(cx.GetJSContext(), mTelemetry, "TELEMETRY_TEST_COUNT"_ns,
+                       false);
+
+  // Accumulate in the histogram
+  {
+    Telemetry::RuntimeAutoCounter autoCounter(Telemetry::TELEMETRY_TEST_COUNT);
+    autoCounter += kExpectedValue / 2;
+  }
+  // This counter should not accumulate since it does not go out of scope
+  Telemetry::RuntimeAutoCounter autoCounter(Telemetry::TELEMETRY_TEST_COUNT);
+  autoCounter += kExpectedValue;
+  // Accumulate a second time in the histogram
+  {
+    Telemetry::RuntimeAutoCounter autoCounter(Telemetry::TELEMETRY_TEST_COUNT);
+    autoCounter += kExpectedValue / 2;
+  }
+  // Get a snapshot for all the histograms
+  JS::RootedValue snapshot(cx.GetJSContext());
+  GetSnapshots(cx.GetJSContext(), mTelemetry, telemetryTestCountName, &snapshot,
+               false);
+
+  // Get the histogram from the snapshot
+  JS::RootedValue histogram(cx.GetJSContext());
+  GetProperty(cx.GetJSContext(), telemetryTestCountName, snapshot, &histogram);
+
+  // Get "sum" property from histogram
+  JS::RootedValue sum(cx.GetJSContext());
+  GetProperty(cx.GetJSContext(), "sum", histogram, &sum);
+
+  // Check that the "sum" stored in the histogram matches with |kExpectedValue|
+  uint32_t uSum = 0;
+  JS::ToUint32(cx.GetJSContext(), sum, &uSum);
+  ASSERT_EQ(uSum, kExpectedValue)
+      << "The histogram is not returning expected value";
+}
+
+TEST_F(TelemetryTestFixture, RuntimeAutoCounterUnderflow) {
+  const uint32_t kExpectedValue = 0;
+  AutoJSContextWithGlobal cx(mCleanGlobal);
+
+  const char* telemetryTestCountName =
+      Telemetry::GetHistogramName(Telemetry::TELEMETRY_TEST_COUNT);
+
+  GetAndClearHistogram(cx.GetJSContext(), mTelemetry, "TELEMETRY_TEST_COUNT"_ns,
+                       false);
+
+  // Accumulate in the histogram
+  {
+    Telemetry::RuntimeAutoCounter autoCounter(Telemetry::TELEMETRY_TEST_COUNT,
+                                              kExpectedValue);
+    autoCounter += -1;
+  }
+
+  // Get a snapshot for all the histograms
+  JS::RootedValue snapshot(cx.GetJSContext());
+  GetSnapshots(cx.GetJSContext(), mTelemetry, telemetryTestCountName, &snapshot,
+               false);
+
+  // Get the histogram from the snapshot
+  JS::RootedValue histogram(cx.GetJSContext());
+  GetProperty(cx.GetJSContext(), telemetryTestCountName, snapshot, &histogram);
+
+  // Get "sum" property from histogram
+  JS::RootedValue sum(cx.GetJSContext());
+  GetProperty(cx.GetJSContext(), "sum", histogram, &sum);
+
+  // Check that the "sum" stored in the histogram matches with |kExpectedValue|
+  uint32_t uSum = 42;
+  JS::ToUint32(cx.GetJSContext(), sum, &uSum);
+  ASSERT_EQ(uSum, kExpectedValue)
+      << "The histogram is supposed to return 0 when an underflow occurs.";
+}