Show max latency on client's status bar

remoting/base/running_samples_unittest.cc

+// Copyright 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include "base/macros.h"
+#include "remoting/base/running_samples.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace remoting {
+
+typedef void (*TestFunction)(size_t i, RunningSamples& samples);
+
+static const int64_t kTestValues[] = { 10, 20, 30, 10, 25, 16, 15 };
+
+// Test framework that verifies average() and max() at beginning, iterates
+// through all elements and meanwhile calls your own test function
+static void TestFramework(int windowSize, TestFunction testFn) {
+  RunningSamples samples(windowSize);
+  EXPECT_EQ(0, samples.Average());
+  EXPECT_EQ(0, samples.Max());
+
+  for (size_t i = 0; i < arraysize(kTestValues); ++i) {
+    samples.Record(kTestValues[i]);
+    testFn(i, samples);
+  }
+}
+
+// Average across a single element, i.e. just return the most recent.
+TEST(RunningSamplesTest, AverageOneElementWindow) {
+  TestFramework(1, [](size_t i, RunningSamples& samples) {
+    EXPECT_EQ(static_cast<double>(kTestValues[i]), samples.Average());
+  });
+}
+
+// Average the two most recent elements.
+TEST(RunningSamplesTest, AverageTwoElementWindow) {
+  TestFramework(2, [](size_t i, RunningSamples& samples) {
+    double expected = kTestValues[i];
+    if (i > 0)
+      expected = (expected + kTestValues[i-1]) / 2;
+
+    EXPECT_EQ(expected, samples.Average());
+  });
+}
+
+// Average across all the elements if the window size exceeds the element count.
+TEST(RunningSamplesTest, AverageLongWindow) {
+  TestFramework(arraysize(kTestValues) + 1,
+      [](size_t i, RunningSamples& samples) {
+    double expected = 0.0;
+    for (size_t j = 0; j <= i; ++j)
+      expected += kTestValues[j];
+    expected /= i + 1;
+
+    EXPECT_EQ(expected, samples.Average());
+  });
+}
+
+// Max of a single element, i.e. just return the most recent.
+TEST(RunningSamplesTest, MaxOneElementWindow) {
+  TestFramework(1, [](size_t i, RunningSamples& samples) {
+    EXPECT_EQ(static_cast<double>(kTestValues[i]), samples.Max());
+  });
+}
+
+// Max of the two most recent elements.
+TEST(RunningSamplesTest, MaxTwoElementWindow) {
+  TestFramework(2, [](size_t i, RunningSamples& samples) {
+    double expected = kTestValues[i];
+    if (i > 0)
+      expected = expected > kTestValues[i-1] ? expected : kTestValues[i-1];
+
+    EXPECT_EQ(expected, samples.Max());
+  });
+}
+
+// Max of all the elements if the window size exceeds the element count.
+TEST(RunningSamplesTest, MaxLongWindow) {
+  TestFramework(arraysize(kTestValues) + 1,
+      [](size_t i, RunningSamples& samples) {
+    int64_t expected = -1;
+    for (size_t j = 0; j <= i; ++j)
+      expected = expected > kTestValues[j] ? expected : kTestValues[j];
+
+    EXPECT_EQ(expected, samples.Max());
+  });
+}
+
+}  // namespace remoting