Method TestUpdateConfig

tests/cpp/test_learner.cc:474–500

 public:
  void TestUpdateConfig() {
    std::unique_ptr<Learner> learner{Learner::Create({Xy_})};
    learner->SetParam("objective", "reg:absoluteerror");
    learner->UpdateOneIter(0, Xy_);
    Json config{Object{}};
    learner->SaveConfig(&config);
    auto base_score = GetBaseScore(config);
    ASSERT_EQ(base_score.size(), 1);
    ASSERT_NE(base_score[0], ObjFunction::DefaultBaseScore());

    // already initialized
    auto Xy1 = RandomDataGenerator{100, Cols(), 0}.Seed(321).GenerateDMatrix(true);
    learner->UpdateOneIter(1, Xy1);
    learner->SaveConfig(&config);
    auto base_score1 = GetBaseScore(config);
    ASSERT_EQ(base_score, base_score1);

    Json model{Object{}};
    learner->SaveModel(&model);
    learner.reset(Learner::Create({}));
    learner->LoadModel(model);
    learner->Configure();
    learner->UpdateOneIter(2, Xy1);
    learner->SaveConfig(&config);
    auto base_score2 = GetBaseScore(config);
    ASSERT_EQ(base_score, base_score2);
  }

  void TestBoostFromAvgParam() {
    std::unique_ptr<Learner> learner{Learner::Create({Xy_})};