* Clean up logic for converting tree_method to updater sequence * Use C++11 enum class for extra safety Compiler will give warnings if switch statements don't handle all possible values of C++11 enum class. Also allow enum class to be used as DMLC parameter. * Fix compiler error + lint * Address reviewer comment * Better docstring for DECLARE_FIELD_ENUM_CLASS * Fix lint * Add C++ test to see if tree_method is recognized * Fix clang-tidy error * Add test_learner.h to R package * Update comments * Fix lint error
This folder contains testcases for xgboost.