diff --git a/R/gutenberg_download.R b/R/gutenberg_download.R
index 57428b0..63b9635 100644
--- a/R/gutenberg_download.R
+++ b/R/gutenberg_download.R
@@ -149,7 +149,13 @@ read_next <- function(possible_urls) {
   }
 }
 
-
+#' Join metadata fields to Gutenberg works
+#'
+#' @param gutenberg_tbl A two column `tbl_df` from `gutenberg_download`.
+#' @inheritParams gutenberg_download
+#'
+#' @return A `tbl_df` of the Gutenberg works with joined metadata.
+#' @keywords internal
 gutenberg_add_metadata <- function(gutenberg_tbl, meta_fields) {
   meta_fields <- union("gutenberg_id", meta_fields)
   dplyr::left_join(
diff --git a/man/gutenberg_add_metadata.Rd b/man/gutenberg_add_metadata.Rd
new file mode 100644
index 0000000..6203989
--- /dev/null
+++ b/man/gutenberg_add_metadata.Rd
@@ -0,0 +1,21 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/gutenberg_download.R
+\name{gutenberg_add_metadata}
+\alias{gutenberg_add_metadata}
+\title{Join metadata fields to Gutenberg works}
+\usage{
+gutenberg_add_metadata(gutenberg_tbl, meta_fields)
+}
+\arguments{
+\item{gutenberg_tbl}{A two column \code{tbl_df} from \code{gutenberg_download}.}
+
+\item{meta_fields}{Additional fields describing each book, such as \code{title}
+and \code{author}, to add from \link{gutenberg_metadata}.}
+}
+\value{
+A \code{tbl_df} of the Gutenberg works with joined metadata.
+}
+\description{
+Join metadata fields to Gutenberg works
+}
+\keyword{internal}
diff --git a/tests/testthat/test-data.R b/tests/testthat/test-data.R
new file mode 100644
index 0000000..259bf5e
--- /dev/null
+++ b/tests/testthat/test-data.R
@@ -0,0 +1,11 @@
+test_that("All four datasets have a date-updated", {
+  d1 <- attr(gutenberg_metadata, "date_updated")
+  d2 <- attr(gutenberg_subjects, "date_updated")
+  d3 <- attr(gutenberg_authors, "date_updated")
+  d4 <- attr(gutenberg_languages, "date_updated")
+
+  expect_s3_class(d1, "Date")
+  expect_s3_class(d2, "Date")
+  expect_s3_class(d3, "Date")
+  expect_s3_class(d4, "Date")
+})
diff --git a/tests/testthat/test-metadata.R b/tests/testthat/test-gutenberg_works.R
similarity index 81%
rename from tests/testthat/test-metadata.R
rename to tests/testthat/test-gutenberg_works.R
index 4301db2..ec87554 100644
--- a/tests/testthat/test-metadata.R
+++ b/tests/testthat/test-gutenberg_works.R
@@ -52,16 +52,3 @@ test_that("gutenberg_works gives error messages with named arguments", {
     "named arguments"
   )
 })
-
-
-test_that("All four datasets have a date-updated", {
-  d1 <- attr(gutenberg_metadata, "date_updated")
-  d2 <- attr(gutenberg_subjects, "date_updated")
-  d3 <- attr(gutenberg_authors, "date_updated")
-  d4 <- attr(gutenberg_languages, "date_updated")
-
-  expect_s3_class(d1, "Date")
-  expect_s3_class(d2, "Date")
-  expect_s3_class(d3, "Date")
-  expect_s3_class(d4, "Date")
-})