Reland of VCMCodecTimer: Change filter from max to 95th percentile

webrtc/modules/video_coding/percentile_filter_unittest.cc

Index: webrtc/modules/video_coding/percentile_filter_unittest.cc
diff --git a/webrtc/modules/video_coding/percentile_filter_unittest.cc b/webrtc/modules/video_coding/percentile_filter_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..8029bdbe194a56ae290724246e4797ed68f00f0b
--- /dev/null
+++ b/webrtc/modules/video_coding/percentile_filter_unittest.cc
@@ -0,0 +1,104 @@
+/*
+ *  Copyright 2016 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include <algorithm>
+
+#include "testing/gtest/include/gtest/gtest.h"
+#include "webrtc/base/constructormagic.h"
+#include "webrtc/modules/video_coding/percentile_filter.h"
+
+namespace webrtc {
+
+class PercentileFilterTest : public ::testing::TestWithParam<float> {
+ public:
+  PercentileFilterTest() : filter_(GetParam()) {
+    // Make sure the tests are deterministic by seeding with a constant.
+    srand(42);
+  }
+
+ protected:
+  PercentileFilter filter_;
+
+ private:
+  RTC_DISALLOW_COPY_AND_ASSIGN(PercentileFilterTest);
+};
+
+INSTANTIATE_TEST_CASE_P(PercentileFilterTests,
+                        PercentileFilterTest,
+                        ::testing::Values(0.0f, 0.1f, 0.5f, 0.9f, 1.0f));
+
+TEST(PercentileFilterTest, MinFilter) {
+  PercentileFilter filter(0.0f);
+  filter.Insert(4);
+  EXPECT_EQ(4, filter.GetPercentileValue());
+  filter.Insert(3);
+  EXPECT_EQ(3, filter.GetPercentileValue());
+}
+
+TEST(PercentileFilterTest, MaxFilter) {
+  PercentileFilter filter(1.0f);
+  filter.Insert(3);
+  EXPECT_EQ(3, filter.GetPercentileValue());
+  filter.Insert(4);
+  EXPECT_EQ(4, filter.GetPercentileValue());
+}
+
+TEST_P(PercentileFilterTest, EmptyFilter) {
+  EXPECT_EQ(0, filter_.GetPercentileValue());
+  filter_.Insert(3);
+  filter_.Erase(3);
+  EXPECT_EQ(0, filter_.GetPercentileValue());
+}
+
+TEST_P(PercentileFilterTest, EraseNonExistingElement) {
+  filter_.Erase(3);
+  EXPECT_EQ(0, filter_.GetPercentileValue());
+  filter_.Insert(4);
+  filter_.Erase(3);
+  EXPECT_EQ(4, filter_.GetPercentileValue());
+}
+
+TEST_P(PercentileFilterTest, DuplicateElements) {
+  filter_.Insert(3);
+  filter_.Insert(3);
+  filter_.Erase(3);
+  EXPECT_EQ(3, filter_.GetPercentileValue());
+}
+
+TEST_P(PercentileFilterTest, InsertAndEraseTenValuesInRandomOrder) {
+  int64_t zero_to_nine[10] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
+  // The percentile value of the ten values above.
+  const int64_t expected_value = static_cast<int64_t>(GetParam() * 9);
+
+  // Insert two sets of |zero_to_nine| in random order.
+  for (int i = 0; i < 2; ++i) {
+    std::random_shuffle(zero_to_nine, zero_to_nine + 10);
+    for (int64_t value : zero_to_nine)
+      filter_.Insert(value);
+    // After inserting a full set of |zero_to_nine|, the percentile should
+    // stay constant.
+    EXPECT_EQ(expected_value, filter_.GetPercentileValue());
+  }
+
+  // Insert and erase sets of |zero_to_nine| in random order a few times.
+  for (int i = 0; i < 3; ++i) {
+    std::random_shuffle(zero_to_nine, zero_to_nine + 10);
+    for (int64_t value : zero_to_nine)
+      filter_.Erase(value);
+    EXPECT_EQ(expected_value, filter_.GetPercentileValue());
+
+    std::random_shuffle(zero_to_nine, zero_to_nine + 10);
+    for (int64_t value : zero_to_nine)
+      filter_.Insert(value);
+    EXPECT_EQ(expected_value, filter_.GetPercentileValue());
+  }
+}
+
+}  // namespace webrtc