Fix bug in resampling when using predict = "train" (#1284) (#1315)

* enable printing pred of resample results when predict type is train

* Finish bug fix and adapt test

* better tests

R/ResamplePrediction.R

@@ -26,14 +26,22 @@ makeResamplePrediction = function(instance, preds.test, preds.train) {
     rbindlist(lapply(seq_along(pr.tr), function(X) cbind(pr.tr[[X]]$data, iter = X, set = "train")))
   ))
 
-  p1 = preds.test[[1L]]
+  if (!any(tenull) && instance$desc$predict %in% c("test", "both")) {
+    p1 = preds.test[[1L]]
+    pall = preds.test
+  } else if (!any(trnull) && instance$desc$predict == "train") {
+    p1 = preds.train[[1L]]
+    pall = preds.train
+  }
+
+
   makeS3Obj(c("ResamplePrediction", class(p1)),
     instance = instance,
     predict.type = p1$predict.type,
     data = data,
     threshold = p1$threshold,
     task.desc = p1$task.desc,
-    time = extractSubList(preds.test, "time")
+    time = extractSubList(pall, "time")
   )
 }
 

tests/testthat/test_base_resample.R

@@ -65,14 +65,24 @@ test_that("resampling, predicting train set works", {
   m = setAggregation(mmce, train.mean)
   r = resample(lrn, multiclass.task, rdesc, measures = m)
   expect_false(is.na(r$aggr["mmce.train.mean"]))
-
+  expect_false(anyNA(r$pred$time))
+  expect_false(is.null(r$pred$predict.type))
+  expect_false(is.null(r$pred$threshold))
+  expect_equal(getTaskDescription(multiclass.task), r$pred$task.desc)
+
   rdesc = makeResampleDesc("CV", iters = 2, predict = "both")
   lrn = makeLearner("classif.rpart")
   m1 = setAggregation(mmce, train.mean)
   m2 = setAggregation(mmce, test.mean)
   r = resample(lrn, multiclass.task, rdesc, measures = list(m1, m2))
   expect_false(is.na(r$aggr["mmce.train.mean"]))
   expect_false(is.na(r$aggr["mmce.test.mean"]))
+  expect_false(anyNA(r$pred$time))
+  expect_false(is.null(r$pred$predict.type))
+  expect_false(is.null(r$pred$threshold))
+  expect_equal(getTaskDescription(multiclass.task), r$pred$task.desc)
+
+
 
 })