fix(prediction): predict_time for no predictions (#1159)

R/worker.R

@@ -326,6 +326,10 @@ workhorse = function(iteration, task, learner, resampling, param_values = NULL,
     lg$debug("Creating Prediction for predict set '%s'", set)
     learner_predict(learner, task, row_ids)
   }, set = predict_sets, row_ids = pred_data$sets, task = pred_data$tasks)
+
+  if (!length(predict_sets)) {
+    learner$state$predict_time = 0L
+  }
   pdatas = discard(pdatas, is.null)
 
   # set the model slot after prediction so it can be sent back to the main process

tests/testthat/test_resample.R

@@ -490,3 +490,10 @@ test_that("resample results works with no predicted predict set", {
   expect_list(tab$prediction, len = 1)
   expect_list(tab$prediction[[1]], len = 0)
 })
+
+test_that("predict_time is 0 if no predict_set is specified", {
+  learner = lrn("classif.featureless", predict_sets = NULL)
+  rr = resample(task, learner, resampling)
+  times = rr$score(msr("time_predict"))$time_predict
+  expect_true(all(times == 0))
+})