Add unit test for #253

tests/testthat/test-clone.R

@@ -1077,6 +1077,28 @@ test_that("Cloning inherited methods for non-portable classes", {
   expect_identical(a$x, 3)
 })
 
+test_that("Unknown environments are not copied nor $-inspected", {
+
+  `$.asdfasdf` <- function(x, value) {
+    stop("error")
+  }
+
+  bar <- R6Class("bar",
+                 public = list(
+                   x = NULL,
+                   initialize = function() {
+                     x <- new.env(parent = emptyenv())
+                     class(x) <- "asdfasdf"
+                     self$x <- x
+                     x
+                   }
+                 )
+  )
+
+  obj <- bar$new()
+  obj2 <- obj$clone(deep = TRUE)
+  expect_equal(obj$x, obj2$x)
+})
 
 test_that("Deep cloning", {
   AC <- R6Class("AC", public = list(x = 1))