also skip base tests on CRAN

Author: pat-s

tests/run-base.R

@@ -1,5 +1,7 @@
 library(testthat)
 
 # no tests on CRAN
-set.seed(getOption("mlr.debug.seed"))
-test_check("mlr", filter = "base_")
+if (identical(Sys.getenv("NOT_CRAN"), "true")) {
+  set.seed(getOption("mlr.debug.seed"))
+  test_check("mlr", filter = "base_")
+}