Allow trials to associate without overriding a feature.

components/variations/variations_seed_processor_unittest.cc

Index: components/variations/variations_seed_processor_unittest.cc
diff --git a/components/variations/variations_seed_processor_unittest.cc b/components/variations/variations_seed_processor_unittest.cc
index d2a2959529aa06fc3f96d641140e0cb7564b29b7..cccacfc45df35ecfe585fef4527ab11a348484af 100644
--- a/components/variations/variations_seed_processor_unittest.cc
+++ b/components/variations/variations_seed_processor_unittest.cc
@@ -359,6 +359,47 @@ TEST_F(VariationsSeedProcessorTest, ValidateStudy) {
   EXPECT_FALSE(processed_study.Init(&study, false));
 }
 
+TEST_F(VariationsSeedProcessorTest, ValidateStudySingleFeature) {
+  Study study;
+  study.set_default_experiment_name("def");
+  Study_Experiment* exp1 = AddExperiment("exp1", 100, &study);
+  Study_Experiment* exp2 = AddExperiment("exp2", 100, &study);
+  Study_Experiment* exp3 = AddExperiment("exp3", 100, &study);
+  AddExperiment("def", 100, &study);
+
+  ProcessedStudy processed_study;
+  EXPECT_TRUE(processed_study.Init(&study, false));
+  EXPECT_EQ(400, processed_study.total_probability());
+
+  EXPECT_EQ(std::string(), processed_study.single_feature_name());
+
+  const char kFeature1Name[] = "Feature1";
+  const char kFeature2Name[] = "Feature2";
+
+  exp1->mutable_feature_association()->add_enable_feature(kFeature1Name);
+  EXPECT_TRUE(processed_study.Init(&study, false));
+  EXPECT_EQ(kFeature1Name, processed_study.single_feature_name());
+
+  exp1->clear_feature_association();
+  exp1->mutable_feature_association()->add_enable_feature(kFeature1Name);
+  exp1->mutable_feature_association()->add_enable_feature(kFeature2Name);
+  EXPECT_TRUE(processed_study.Init(&study, false));
+  EXPECT_EQ(std::string(), processed_study.single_feature_name());

[rkaplow, 2016/03/17 15:08:48]

maybe note what this is testing (multiple features make s_f_n unset).

[Alexei Svitkine (slow), 2016/03/17 15:24:59]

Done.

+
+  exp1->clear_feature_association();
+  exp1->mutable_feature_association()->add_enable_feature(kFeature1Name);
+  exp2->mutable_feature_association()->add_enable_feature(kFeature1Name);
+  exp3->mutable_feature_association()->add_disable_feature(kFeature1Name);
+  EXPECT_TRUE(processed_study.Init(&study, false));
+  EXPECT_EQ(kFeature1Name, processed_study.single_feature_name());
+
+  // Setting a different feature name on exp2 should cause |single_feature_name|
+  // to be not set.
+  exp2->mutable_feature_association()->set_enable_feature(0, kFeature2Name);
+  EXPECT_TRUE(processed_study.Init(&study, false));
+  EXPECT_EQ(std::string(), processed_study.single_feature_name());
+}
+
 TEST_F(VariationsSeedProcessorTest, ProcessedStudyAllAssignmentsToOneGroup) {
   Study study;
   study.set_default_experiment_name("def");
@@ -613,14 +654,13 @@ TEST_F(VariationsSeedProcessorTest, FeatureAssociationAndForcing) {
       // Check what happens without and command-line forcing flags - that the
       // |one_hundred_percent_group| gets correctly selected and does the right
       // thing w.r.t. to affecting the feature / activating the trial.
-      {kFeatureOffByDefault, "", "", DEFAULT_GROUP, kDefaultGroup, false,
-       false},
+      {kFeatureOffByDefault, "", "", DEFAULT_GROUP, kDefaultGroup, false, true},
       {kFeatureOffByDefault, "", "", ENABLE_GROUP, kEnabledGroup, true, true},
       {kFeatureOffByDefault, "", "", DISABLE_GROUP, kDisabledGroup, false,
        true},
 
       // Do the same as above, but for kFeatureOnByDefault feature.
-      {kFeatureOnByDefault, "", "", DEFAULT_GROUP, kDefaultGroup, true, false},
+      {kFeatureOnByDefault, "", "", DEFAULT_GROUP, kDefaultGroup, true, true},
       {kFeatureOnByDefault, "", "", ENABLE_GROUP, kEnabledGroup, true, true},
       {kFeatureOnByDefault, "", "", DISABLE_GROUP, kDisabledGroup, false, true},