[Most Visited] Log suggestion provider to UMA

chrome/browser/search/most_visited_iframe_source_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 "base/bind.h"
 #include "base/metrics/histogram.h"
 #include "base/metrics/statistics_recorder.h"
+#include "base/strings/stringprintf.h"
 #include "chrome/browser/search/most_visited_iframe_source.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 class MostVisitedIframeSourceTest : public testing::Test {
  public:
   void ExpectNullData(base::RefCountedMemory* data) {
     EXPECT_EQ(NULL, data);
   }
 
  protected:
   MostVisitedIframeSource* source() { return source_.get(); }
 
  private:
   virtual void SetUp() { source_.reset(new MostVisitedIframeSource()); }
 
   scoped_ptr<MostVisitedIframeSource> source_;
 };
 
-TEST_F(MostVisitedIframeSourceTest, LogEndpointIsValid) {
+TEST_F(MostVisitedIframeSourceTest, LogEndpointIsValidNoProvider) {
   content::URLDataSource::GotDataCallback callback = base::Bind(
       &MostVisitedIframeSourceTest::ExpectNullData, base::Unretained(this));
 
   base::StatisticsRecorder::Initialize();
   // Making sure the histogram is created.
   UMA_HISTOGRAM_ENUMERATION(MostVisitedIframeSource::kMostVisitedHistogramName,
                             0, MostVisitedIframeSource::kNumMostVisited);
 
   base::HistogramBase* histogram = base::StatisticsRecorder::FindHistogram(
       MostVisitedIframeSource::kMostVisitedHistogramName);
@@ skipping 19 matching lines @@
   EXPECT_EQ(1, samples3->GetCount(5));
   EXPECT_EQ(2, samples3->GetCount(1));
 
   // If 'pos' is unspecified or invalid, callback still gets called but values
   // are not incremented.
   source()->StartDataRequest("log.html?pos=", 0, 0, callback);
   source()->StartDataRequest("log.html", 0, 0, callback);
   // Total count hasn't changed.
   EXPECT_EQ(samples2->TotalCount() + 2, samples3->TotalCount());
 }
+
+TEST_F(MostVisitedIframeSourceTest, LogEndpointIsValidWithProvider) {
+  content::URLDataSource::GotDataCallback callback = base::Bind(
+      &MostVisitedIframeSourceTest::ExpectNullData, base::Unretained(this));
+
+  base::StatisticsRecorder::Initialize();
+  // Making sure a test histogram with provider is created by logging a dummy
+  // value.
+  const std::string histogram_name =
+      MostVisitedIframeSource::GetHistogramNameForProvider("foobar");
+  UMA_HISTOGRAM_ENUMERATION(histogram_name, 0,
+                            MostVisitedIframeSource::kNumMostVisited);
+
+  base::HistogramBase* histogram = base::StatisticsRecorder::FindHistogram(
+      histogram_name);
+  scoped_ptr<base::HistogramSamples> samples1(histogram->SnapshotSamples());
+  // The dummy value got logged.
+  EXPECT_EQ(1, samples1->TotalCount());
+  EXPECT_EQ(1, samples1->GetCount(0));
+
+  // Test the method.
+  source()->StartDataRequest("log.html?pos=1&pr=foobar", 0, 0, callback);
+
+  scoped_ptr<base::HistogramSamples> samples2(histogram->SnapshotSamples());
+  EXPECT_EQ(samples1->TotalCount() + 1, samples2->TotalCount());
+  EXPECT_EQ(1, samples2->GetCount(1));
+
+  // Counts accumulate and behave as expected.
+  source()->StartDataRequest("log.html?pos=5&pr=foobar", 0, 0, callback);
+  source()->StartDataRequest("log.html?pos=1&pr=foobar", 0, 0, callback);
+  // This should have no effect for the "foobar" histogram.
+  source()->StartDataRequest("log.html?pos=1&pr=nofoo", 0, 0, callback);
+
+  scoped_ptr<base::HistogramSamples> samples3(histogram->SnapshotSamples());
+  EXPECT_EQ(samples2->TotalCount() + 2, samples3->TotalCount());
+  EXPECT_EQ(1, samples3->GetCount(5));
+  EXPECT_EQ(2, samples3->GetCount(1));
+}