Adding performance tests for HQP that represent importance of optimising HistoryItemsForTerms method

testing/perf/scoped_histogram_result_printer_unittest.cc

+// Copyright (c) 2016 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 "testing/perf/scoped_histogram_result_printer.h"
+
+#include "base/metrics/histogram_macros.h"
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest-spi.h"
+
+namespace {
+using testing::_;
+
+const char kFakeHistogram[] = "FakeHistogramName";
+const char kFakeMeasurement[] = "FakeMeasurement";
+
+struct MockedPrinter {
+  MOCK_METHOD2(PrintHistogram,
+               void(const base::HistogramSamples&, const std::string&));
+  perf_test::HistogramPrinter GetCallback() {
+    return base::Bind(&MockedPrinter::PrintHistogram, base::Unretained(this));
+  }
+};
+
+void StrictIsNotFoundTest() {
+  MockedPrinter perf_printer;
+  EXPECT_CALL(perf_printer, PrintHistogram(_, _)).Times(0);
+
+  perf_test::ScopedHistogramResultPrinter scoped_printer(
+      perf_printer.GetCallback());
+
+  scoped_printer.AddHistogramStrict(kFakeHistogram, kFakeMeasurement);
+}
+
+void NothingIsAddedToStrictTest() {
+  MockedPrinter perf_printer;
+  EXPECT_CALL(perf_printer, PrintHistogram(_, _)).Times(0);
+
+  { SCOPED_UMA_HISTOGRAM_TIMER(kFakeHistogram); }
+
+  perf_test::ScopedHistogramResultPrinter scoped_printer(
+      perf_printer.GetCallback());
+
+  scoped_printer.AddHistogramStrict(kFakeHistogram, kFakeMeasurement);
+}
+
+}  // namespace
+
+namespace perf_test {
+
+class ScopedHistogramResultPrinterTest : public testing::Test {};
+
+TEST_F(ScopedHistogramResultPrinterTest, StrictIsNotFound) {
+  EXPECT_NONFATAL_FAILURE(StrictIsNotFoundTest(), " wasn't found");
+}
+
+TEST_F(ScopedHistogramResultPrinterTest, StrictIsFound) {
+  MockedPrinter perf_printer;
+  EXPECT_CALL(perf_printer, PrintHistogram(_, _));
+
+  ScopedHistogramResultPrinter scoped_printer(perf_printer.GetCallback());
+
+  scoped_printer.AddHistogramStrict(kFakeHistogram, kFakeMeasurement);
+  SCOPED_UMA_HISTOGRAM_TIMER(kFakeHistogram);
+}
+
+TEST_F(ScopedHistogramResultPrinterTest, NothingIsAddedToStrict) {
+  EXPECT_NONFATAL_FAILURE(NothingIsAddedToStrictTest(),
+                          "Nothing was added in ");
+}
+
+TEST_F(ScopedHistogramResultPrinterTest, NiceIsNotFound) {
+  MockedPrinter perf_printer;
+  EXPECT_CALL(perf_printer, PrintHistogram(_, _)).Times(0);
+
+  ScopedHistogramResultPrinter scoped_printer(perf_printer.GetCallback());
+
+  scoped_printer.AddHistogramNice(kFakeHistogram, kFakeMeasurement);
+}
+
+TEST_F(ScopedHistogramResultPrinterTest, NothingIsAddedToNice) {
+  MockedPrinter perf_printer;
+  EXPECT_CALL(perf_printer, PrintHistogram(_, _)).Times(0);
+
+  { SCOPED_UMA_HISTOGRAM_TIMER(kFakeHistogram); }
+  ScopedHistogramResultPrinter scoped_printer(perf_printer.GetCallback());
+  scoped_printer.AddHistogramNice(kFakeHistogram, kFakeMeasurement);
+}
+
+}  // namespace  perf_test