Parallelizable download metrics.

content/browser/download/download_stats_unittest.cc

Index: content/browser/download/download_stats_unittest.cc
diff --git a/content/browser/download/download_stats_unittest.cc b/content/browser/download/download_stats_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..042c113db42480e5bd240394ad9917c93f8f3e3e
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+++ b/content/browser/download/download_stats_unittest.cc
@@ -0,0 +1,48 @@
+// Copyright 2017 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 "content/browser/download/download_stats.h"
+
+#include "base/test/histogram_tester.h"
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace content {
+
+namespace {
+
+void VerfiyParallelizableAverageStats(int64_t bytes_downloaded,
+                                      const base::TimeDelta& time_span,
+                                      const std::string& expected_suffix) {
+  base::HistogramTester histogram_tester;
+  int64_t expected_bandwidth = bytes_downloaded / time_span.InSeconds();
+
+  RecordParallelizableDownloadAverageStats(bytes_downloaded, time_span);
+  histogram_tester.ExpectBucketCount("Download.ParallelizableDownloadBandwidth",
+                                     expected_bandwidth, 1);
+  histogram_tester.ExpectBucketCount("Download.Parallelizable.DownloadTime",
+                                     time_span.InMilliseconds(), 1);
+  histogram_tester.ExpectBucketCount("Download.Parallelizable.FileSize",
+                                     bytes_downloaded / 1024, 1);
+  histogram_tester.ExpectBucketCount(
+      "Download.ParallelizableDownloadBandwidth." + expected_suffix,
+      expected_bandwidth, 1);
+  histogram_tester.ExpectBucketCount(
+      "Download.Parallelizable.DownloadTime." + expected_suffix,
+      time_span.InMilliseconds(), 1);
+}
+
+}  // namespace
+
+TEST(DownloadStatsTest, ParallelizableAverageStatsSmall) {
+  // Lowest bucket of the file size suffix.
+  VerfiyParallelizableAverageStats(1, base::TimeDelta::FromSeconds(1), "0.5MB");
+  VerfiyParallelizableAverageStats(1024 * 1024 * 20,
+                                   base::TimeDelta::FromSeconds(10), "50MB");
+  // Overflow bucket of the file size suffix.
+  VerfiyParallelizableAverageStats(1024 * 1024 * 1024,
+                                   base::TimeDelta::FromSeconds(1), "GT50MB");
+}
+
+}  // namespace content