Add test that model paramaters are accessible within R

R-package/tests/testthat/test_parameter_exposure.R

@@ -0,0 +1,32 @@
+context('Test model params and call are exposed to R')
+
+require(xgboost)
+
+data(agaricus.train, package='xgboost')
+data(agaricus.test, package='xgboost')
+
+dtrain <- xgb.DMatrix(agaricus.train$data, label = agaricus.train$label)
+dtest <- xgb.DMatrix(agaricus.test$data, label = agaricus.test$label)
+
+bst <- xgboost(data = dtrain,
+               max.depth = 2,
+               eta = 1,
+               nround = 10,
+               nthread = 1,
+               verbose = 0,
+               objective = "binary:logistic")
+
+test_that("call is exposed to R", {
+  model_call <- attr(bst, "call")
+  expect_is(model_call, "call")
+})
+
+test_that("params is exposed to R", {
+  model_params <- attr(bst, "params")
+
+  expect_is(model_params, "list")
+
+  expect_equal(model_params$eta, 1)
+  expect_equal(model_params$max.depth, 2)
+  expect_equal(model_params$objective, "binary:logistic")
+})