Added tests for storing and loading seed data to and from prefs.

chrome/browser/metrics/variations_service_unittest.cc

 // Copyright (c) 2012 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/base64.h"
 #include "chrome/browser/metrics/proto/study.pb.h"
 #include "chrome/browser/metrics/variations_service.h"
 #include "chrome/common/chrome_version_info.h"
+#include "chrome/common/pref_names.h"
+#include "chrome/test/base/testing_pref_service.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace chrome_variations {
 
 namespace {
 
 // Converts |time| to Study proto format.
 int64 TimeToProtoTime(const base::Time& time) {
   return (time - base::Time::UnixEpoch()).InSeconds();
 }
 
+// Populates |seed| with simple test data. The resulting seed will contain one
+// study called "test", which contains one experiment called "abc" with
+// probability weight 100. |seed|'s study field will be cleared before adding
+// the new study.
+void CreateTestSeed(chrome_variations::TrialsSeed* seed) {

[SteveT, 2012/07/09 19:23:26]

nit: DCHECK(seed);

[SteveT, 2012/07/09 19:23:26]

You currently don't use these seeds more than once in a test. Would it be
cleaner to just have this function return a chrome_variations::TrialSeed object
rather than passing around pointers?

If not, then maybe PopulateTestSeed is a better name.

[jwd, 2012/07/09 21:08:13]

Done.

[jwd, 2012/07/09 21:08:13]

Done.

+  seed->clear_study();
+  chrome_variations::Study* study = seed->add_study();
+  study->set_name("test");
+  study->set_default_experiment_name("abc");
+  chrome_variations::Study_Experiment* experiment = study->add_experiment();
+  experiment->set_name("abc");
+  experiment->set_probability_weight(100);
+}
+
 }  // namespace
 
 TEST(VariationsServiceTest, CheckStudyChannel) {
   const chrome::VersionInfo::Channel channels[] = {
     chrome::VersionInfo::CHANNEL_CANARY,
     chrome::VersionInfo::CHANNEL_DEV,
     chrome::VersionInfo::CHANNEL_BETA,
     chrome::VersionInfo::CHANNEL_STABLE,
   };
   const Study_Channel study_channels[] = {
@@ skipping 296 matching lines @@
       &total_probability);
   ASSERT_TRUE(valid);
   Study_Experiment* repeated_group = study.add_experiment();
   repeated_group->set_name("abc");
   repeated_group->set_probability_weight(1);
   valid = VariationsService::ValidateStudyAndComputeTotalProbability(study,
       &total_probability);
   EXPECT_FALSE(valid);
 }
 
+TEST(VariationsServiceTest, StoreSeed) {
+  TestingPrefService pref_service;
+
+  VariationsService::RegisterPrefs(&pref_service);
+  const base::Time now = base::Time::Now();
+
+  chrome_variations::TrialsSeed seed;
+  CreateTestSeed(&seed);
+
+  VariationsService variations_service;
+  std::string serialized_seed;
+  seed.SerializeToString(&serialized_seed);
+  variations_service.StoreSeedData(serialized_seed, now, &pref_service);
+  // Make sure the pref was actually set.
+  EXPECT_FALSE(
+      pref_service.FindPreference(prefs::kVariationsSeed)->IsDefaultValue());
+
+  std::string loaded_serialized_seed =
+      pref_service.GetString(prefs::kVariationsSeed);
+  std::string decoded_serialized_seed;
+  ASSERT_TRUE(base::Base64Decode(loaded_serialized_seed,
+                                 &decoded_serialized_seed));
+  // Make sure the stored seed from pref is the same as the seed we created.
+  EXPECT_EQ(serialized_seed, decoded_serialized_seed);
+
+  // Check if trying to store a bad seed leaves the pref unchanged.
+  pref_service.ClearPref(prefs::kVariationsSeed);
+  variations_service.StoreSeedData("this should fail", now, &pref_service);

[SteveT, 2012/07/09 19:23:26]

Optional: Might be nice to have StoreSeedData return a bool indicating success,
so we can test that value here. On the other hand, your check below may be
sufficient in indicating as such.

[jwd, 2012/07/09 21:08:13]

Done.

+  EXPECT_TRUE(
+      pref_service.FindPreference(prefs::kVariationsSeed)->IsDefaultValue());
+}
+
+TEST(VariationsServiceTest, LoadSeed) {
+  TestingPrefService pref_service;
+
+  VariationsService::RegisterPrefs(&pref_service);
+
+  // Store good seed data to test if loading from prefs works.
+  chrome_variations::TrialsSeed seed;
+  CreateTestSeed(&seed);
+
+  std::string serialized_seed;
+  seed.SerializeToString(&serialized_seed);
+  std::string base64_serialized_seed;
+  ASSERT_TRUE(base::Base64Encode(serialized_seed, &base64_serialized_seed));
+  pref_service.SetString(prefs::kVariationsSeed, base64_serialized_seed);
+
+  VariationsService variations_service;
+  chrome_variations::TrialsSeed loaded_seed;
+  EXPECT_TRUE(
+      variations_service.LoadTrialsSeedFromPref(&pref_service, &loaded_seed));
+
+  std::string serialized_loaded_seed;
+  loaded_seed.SerializeToString(&serialized_loaded_seed);
+  // Check that the loaded data is the same as the original.
+  EXPECT_EQ(serialized_seed, serialized_loaded_seed);
+  // Make sure the pref hasn't been changed.
+  EXPECT_FALSE(
+      pref_service.FindPreference(prefs::kVariationsSeed)->IsDefaultValue());
+  EXPECT_EQ(base64_serialized_seed,
+            pref_service.GetString(prefs::kVariationsSeed));
+
+  // Check that loading a bad seed returns false and clears the pref.
+  pref_service.ClearPref(prefs::kVariationsSeed);
+  pref_service.SetString(prefs::kVariationsSeed, "this should fail");

[SteveT, 2012/07/09 19:23:26]

Would this be useful to ensure that we're actually doing work here?
EXPECT_FALSE(
    pref_service.FindPreference(prefs::kVariationsSeed)->IsDefaultValue());

[jwd, 2012/07/09 21:08:13]

Done. Might as well. 

+  EXPECT_FALSE(
+      variations_service.LoadTrialsSeedFromPref(&pref_service, &loaded_seed));
+  EXPECT_TRUE(
+      pref_service.FindPreference(prefs::kVariationsSeed)->IsDefaultValue());
+}
+
 }  // namespace chrome_variations