Implement shortcut for finalizing a trial with all remaining probability...

base/field_trial_unittest.cc

-// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
+// Copyright (c) 2006-2009 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.
 
 // Test of FieldTrial class
 
 #include "base/field_trial.h"
 
 #include "base/string_util.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ skipping 50 matching lines @@
     EXPECT_EQ(trial_true->group(), winner_group);
     EXPECT_EQ(trial_true->group_name(), winner);
 
     FieldTrial* trial_false = new FieldTrial(always_false, 10);
     int loser_group = trial_false->AppendGroup("ALoser", 0);
 
     EXPECT_NE(trial_false->group(), loser_group);
   }
 }
 
+TEST_F(FieldTrialTest, RemainingProbability) {
+  // First create a test that hasn't had a winner yet.
+  const std::string winner = "Winner";
+  const std::string loser = "Loser";
+  scoped_refptr<FieldTrial> trial;
+  int counter = 0;
+  do {
+    std::string name = StringPrintf("trial%d", ++counter);
+    trial = new FieldTrial(name, 10);
+    trial->AppendGroup(loser, 5);  // 50% chance of not being chosen.
+  } while (trial->group() != FieldTrial::kNotParticipating);
+
+  // Now add a winner with all remaining probability.
+  trial->AppendGroup(winner, FieldTrial::kAllRemainingProbability);
+
+  // And that winner should ALWAYS win.
+  EXPECT_EQ(winner, trial->group_name());
+}
+
 TEST_F(FieldTrialTest, MiddleProbabilities) {
   char name[] = " same name";
   bool false_event_seen = false;
   bool true_event_seen = false;
   for (int i = 1; i < 250; ++i) {
     name[0] = i;
     FieldTrial* trial = new FieldTrial(name, 10);
     int might_win = trial->AppendGroup("MightWin", 5);
 
     if (trial->group() == might_win) {
@@ skipping 88 matching lines @@
   std::string save_string;
   FieldTrialList::StatesToString(&save_string);
   EXPECT_EQ("Some name/Winner/", save_string);
 
   // It is OK if we redundantly specify a winner.
   EXPECT_TRUE(FieldTrialList::StringAugmentsState(save_string));
 
   // But it is an error to try to change to a different winner.
   EXPECT_FALSE(FieldTrialList::StringAugmentsState("Some name/Loser/"));
 }