diff --git a/NAMESPACE b/NAMESPACE
index 949b8da..e8b2fd4 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -1,5 +1,6 @@
 # Generated by roxygen2: do not edit by hand
 
+export(.testPrepExtendedComment)
 export(addMapping)
 export(cacheCleanup)
 export(cacheCopy)
diff --git a/R/prepExtendedComment.R b/R/prepExtendedComment.R
index 7357760..a0f111c 100644
--- a/R/prepExtendedComment.R
+++ b/R/prepExtendedComment.R
@@ -25,7 +25,7 @@ prepExtendedComment <- function(x, type = "#undefined", warn = TRUE, n = 1) {
 
   # if readSource is called as madrat::readSource functionName will
   # be in this unintuitive order c("::", "madrat", "readSource")
-  if (length(functionCall) == 3 && functionCall[[1]] %in% c("::", ":::")) {
+  if (length(functionCall) == 3 && functionCall[[1]] == "::") {
     f <- get(functionCall[[3]], envir = loadNamespace(functionCall[[2]]), mode = "function", sys.frame(-n - 1))
   } else {
     f <- get(functionCall, mode = "function", sys.frame(-n - 1))
@@ -60,7 +60,11 @@ prepExtendedComment <- function(x, type = "#undefined", warn = TRUE, n = 1) {
   return(extendedComment)
 }
 
-# this exists only for testing purposes
-testPrepExtendedComment <- function() {
+#' .testPrepExtendedComment
+#'
+#' This function exists only for testing purposes.
+#'
+#' @export
+.testPrepExtendedComment <- function() {
   return(prepExtendedComment(list(unit = "m", description = "example", package = "blub")))
 }
diff --git a/man/dot-testPrepExtendedComment.Rd b/man/dot-testPrepExtendedComment.Rd
new file mode 100644
index 0000000..e42a12f
--- /dev/null
+++ b/man/dot-testPrepExtendedComment.Rd
@@ -0,0 +1,11 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/prepExtendedComment.R
+\name{.testPrepExtendedComment}
+\alias{.testPrepExtendedComment}
+\title{.testPrepExtendedComment}
+\usage{
+.testPrepExtendedComment()
+}
+\description{
+This function exists only for testing purposes.
+}
diff --git a/tests/testthat/test-prepExtendedComment.R b/tests/testthat/test-prepExtendedComment.R
index 761e260..e378dc6 100644
--- a/tests/testthat/test-prepExtendedComment.R
+++ b/tests/testthat/test-prepExtendedComment.R
@@ -1,6 +1,6 @@
 test_that("prepExtendedComment works in functions called via package::fun", {
   # need to run in separate R session to make sure madrat is not attached / loaded via load_all
-  expect_identical(callr::r(function() madrat:::testPrepExtendedComment()[1:2]),
+  expect_identical(callr::r(function() madrat::.testPrepExtendedComment()[1:2]),
                    c(" description: example",
                      " unit: m"))
 })