From 1cff5108e1130bee79e82bfdada3fdd439bad280 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Tue, 10 Mar 2026 12:42:47 +0000
Subject: [PATCH 1/8] Initial plan


From 8f8022ac061aefc7e1642c86982eeb7b83a5280f Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Tue, 10 Mar 2026 12:50:47 +0000
Subject: [PATCH 2/8] feat: add finalize_doubles() (#10)

Co-authored-by: jonthegeek <33983824+jonthegeek@users.noreply.github.com>
---
 DESCRIPTION                            |  3 ++
 NAMESPACE                              |  1 +
 NEWS.md                                |  4 ++
 R/finalize_doubles.R                   | 22 +++++++++++
 man/datawrap-package.Rd                |  2 +-
 man/finalize_doubles.Rd                | 25 +++++++++++++
 tests/testthat/test-finalize_doubles.R | 51 ++++++++++++++++++++++++++
 7 files changed, 107 insertions(+), 1 deletion(-)
 create mode 100644 NEWS.md
 create mode 100644 R/finalize_doubles.R
 create mode 100644 man/finalize_doubles.Rd
 create mode 100644 tests/testthat/test-finalize_doubles.R

diff --git a/DESCRIPTION b/DESCRIPTION
index 08cdde2..759bd67 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -14,9 +14,12 @@ Imports:
     knitr,
     purrr,
     rlang,
+    stbl,
     stringr,
     tibble,
     vctrs
+Remotes:
+    stbl=wranglezone/stbl
 Suggests:
     testthat (>= 3.0.0),
     usethis,
diff --git a/NAMESPACE b/NAMESPACE
index 385e453..9e71e1d 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -2,4 +2,5 @@
 
 export(create_dataset_dictionary)
 export(describe_dataset)
+export(finalize_doubles)
 export(write_dataset_dictionary)
diff --git a/NEWS.md b/NEWS.md
new file mode 100644
index 0000000..3ea0dfc
--- /dev/null
+++ b/NEWS.md
@@ -0,0 +1,4 @@
+# datawrap (development version)
+
+* `finalize_doubles()` converts integer-valued double columns to integer for
+  efficient storage (@copilot, #10).
diff --git a/R/finalize_doubles.R b/R/finalize_doubles.R
new file mode 100644
index 0000000..1bef8ba
--- /dev/null
+++ b/R/finalize_doubles.R
@@ -0,0 +1,22 @@
+#' Downcast integer-valued double columns to integer
+#'
+#' Iterates over all columns in `dataset` and converts any double column whose
+#' values can all be represented as integers (as determined by
+#' `stbl::is_int_ish()`) to integer using `stbl::to_int()`. Columns that are
+#' not doubles, or that contain non-integer-valued data, are left unchanged.
+#'
+#' @param dataset (`data.frame`) The dataset to process.
+#'
+#' @returns The `dataset` with all safely-downcasted double columns converted to
+#'   integer.
+#' @export
+#'
+#' @examples
+#' df <- data.frame(x = c(1.0, 2.0, 3.0), y = c(1.1, 2.2, 3.3))
+#' finalize_doubles(df)
+finalize_doubles <- function(dataset) {
+  int_ish_cols <- purrr::map_lgl(dataset, is.double) &
+    purrr::map_lgl(dataset, stbl::is_int_ish)
+  dataset[int_ish_cols] <- lapply(dataset[int_ish_cols], stbl::to_int)
+  dataset
+}
diff --git a/man/datawrap-package.Rd b/man/datawrap-package.Rd
index 82d7860..533de11 100644
--- a/man/datawrap-package.Rd
+++ b/man/datawrap-package.Rd
@@ -11,8 +11,8 @@ Helpers to create data dictionaries, document package datasets, and apply finish
 \seealso{
 Useful links:
 \itemize{
-  \item \url{https://github.com/wranglezone/datawrap}
   \item \url{https://wranglezone.github.io/datawrap/}
+  \item \url{https://github.com/wranglezone/datawrap}
   \item Report bugs at \url{https://github.com/wranglezone/datawrap/issues}
 }
 
diff --git a/man/finalize_doubles.Rd b/man/finalize_doubles.Rd
new file mode 100644
index 0000000..6293948
--- /dev/null
+++ b/man/finalize_doubles.Rd
@@ -0,0 +1,25 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/finalize_doubles.R
+\name{finalize_doubles}
+\alias{finalize_doubles}
+\title{Downcast integer-valued double columns to integer}
+\usage{
+finalize_doubles(dataset)
+}
+\arguments{
+\item{dataset}{(\code{data.frame}) The dataset to process.}
+}
+\value{
+The \code{dataset} with all safely-downcasted double columns converted to
+integer.
+}
+\description{
+Iterates over all columns in \code{dataset} and converts any double column whose
+values can all be represented as integers (as determined by
+\code{stbl::is_int_ish()}) to integer using \code{stbl::to_int()}. Columns that are
+not doubles, or that contain non-integer-valued data, are left unchanged.
+}
+\examples{
+df <- data.frame(x = c(1.0, 2.0, 3.0), y = c(1.1, 2.2, 3.3))
+finalize_doubles(df)
+}
diff --git a/tests/testthat/test-finalize_doubles.R b/tests/testthat/test-finalize_doubles.R
new file mode 100644
index 0000000..48c70ec
--- /dev/null
+++ b/tests/testthat/test-finalize_doubles.R
@@ -0,0 +1,51 @@
+# finalize_doubles() -----------------------------------------------------------
+
+test_that("finalize_doubles() converts integer-valued double columns to integer (#10)", {
+  df <- data.frame(x = c(1.0, 2.0, 3.0), y = c(1.1, 2.2, 3.3))
+  result <- finalize_doubles(df)
+  expect_type(result$x, "integer")
+  expect_type(result$y, "double")
+})
+
+test_that("finalize_doubles() leaves non-double columns unchanged (#10)", {
+  df <- data.frame(
+    x = c(1.0, 2.0),
+    y = letters[1:2],
+    z = TRUE,
+    stringsAsFactors = FALSE
+  )
+  result <- finalize_doubles(df)
+  expect_type(result$y, "character")
+  expect_type(result$z, "logical")
+})
+
+test_that("finalize_doubles() preserves NA values in converted columns (#10)", {
+  df <- data.frame(x = c(1.0, NA, 3.0))
+  result <- finalize_doubles(df)
+  expect_type(result$x, "integer")
+  expect_true(is.na(result$x[[2]]))
+})
+
+test_that("finalize_doubles() does not convert already-integer columns (#10)", {
+  df <- data.frame(x = 1L)
+  result <- finalize_doubles(df)
+  expect_type(result$x, "integer")
+})
+
+test_that("finalize_doubles() returns a data frame (#10)", {
+  df <- data.frame(x = c(1.0, 2.0))
+  result <- finalize_doubles(df)
+  expect_s3_class(result, "data.frame")
+})
+
+test_that("finalize_doubles() handles a dataset with no double columns (#10)", {
+  df <- data.frame(x = 1L, y = "a", stringsAsFactors = FALSE)
+  result <- finalize_doubles(df)
+  expect_identical(result, df)
+})
+
+test_that("finalize_doubles() handles an empty data frame (#10)", {
+  df <- data.frame()
+  result <- finalize_doubles(df)
+  expect_identical(result, df)
+})

From c19c394b88c2b732ff6d11daeb05dc4a9b46aa47 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Tue, 10 Mar 2026 13:06:40 +0000
Subject: [PATCH 3/8] fix: address review feedback on finalize_doubles()

Co-authored-by: jonthegeek <33983824+jonthegeek@users.noreply.github.com>
---
 R/finalize_doubles.R                   |  9 ++++++++-
 tests/testthat/test-finalize_doubles.R | 18 ++++++++++--------
 2 files changed, 18 insertions(+), 9 deletions(-)

diff --git a/R/finalize_doubles.R b/R/finalize_doubles.R
index 1bef8ba..76cc788 100644
--- a/R/finalize_doubles.R
+++ b/R/finalize_doubles.R
@@ -15,8 +15,15 @@
 #' df <- data.frame(x = c(1.0, 2.0, 3.0), y = c(1.1, 2.2, 3.3))
 #' finalize_doubles(df)
 finalize_doubles <- function(dataset) {
+  if (!is.data.frame(dataset)) {
+    stbl::pkg_abort(
+      "datawrap",
+      "{.arg dataset} must be a {.cls data.frame}.",
+      "invalid_argument"
+    )
+  }
   int_ish_cols <- purrr::map_lgl(dataset, is.double) &
     purrr::map_lgl(dataset, stbl::is_int_ish)
-  dataset[int_ish_cols] <- lapply(dataset[int_ish_cols], stbl::to_int)
+  dataset[int_ish_cols] <- purrr::map(dataset[int_ish_cols], stbl::to_int)
   dataset
 }
diff --git a/tests/testthat/test-finalize_doubles.R b/tests/testthat/test-finalize_doubles.R
index 48c70ec..c958b01 100644
--- a/tests/testthat/test-finalize_doubles.R
+++ b/tests/testthat/test-finalize_doubles.R
@@ -26,16 +26,18 @@ test_that("finalize_doubles() preserves NA values in converted columns (#10)", {
   expect_true(is.na(result$x[[2]]))
 })
 
-test_that("finalize_doubles() does not convert already-integer columns (#10)", {
-  df <- data.frame(x = 1L)
-  result <- finalize_doubles(df)
-  expect_type(result$x, "integer")
+test_that("finalize_doubles() preserves the class of the input (#10)", {
+  tbl <- tibble::tibble(x = c(1.0, 2.0))
+  result <- finalize_doubles(tbl)
+  expect_identical(class(result), class(tbl))
 })
 
-test_that("finalize_doubles() returns a data frame (#10)", {
-  df <- data.frame(x = c(1.0, 2.0))
-  result <- finalize_doubles(df)
-  expect_s3_class(result, "data.frame")
+test_that("finalize_doubles() errors if dataset is not a data.frame (#10)", {
+  stbl::expect_pkg_error_classes(
+    finalize_doubles(list(x = 1.0)),
+    "datawrap",
+    "invalid_argument"
+  )
 })
 
 test_that("finalize_doubles() handles a dataset with no double columns (#10)", {

From 63b5e3d2af1bc2278c2c3e9c362917be768802d6 Mon Sep 17 00:00:00 2001
From: Jon Harmon <jonthegeek@gmail.com>
Date: Tue, 10 Mar 2026 09:17:46 -0500
Subject: [PATCH 4/8] Tweaks that are harder to explain than to implement.

---
 DESCRIPTION                            |  4 ++--
 R/finalize_doubles.R                   | 14 +++++++-------
 tests/testthat/test-finalize_doubles.R | 22 +++++++++++++++-------
 3 files changed, 24 insertions(+), 16 deletions(-)

diff --git a/DESCRIPTION b/DESCRIPTION
index 759bd67..5bce19f 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -18,12 +18,12 @@ Imports:
     stringr,
     tibble,
     vctrs
-Remotes:
-    stbl=wranglezone/stbl
 Suggests:
     testthat (>= 3.0.0),
     usethis,
     withr
+Remotes:
+    stbl=wranglezone/stbl
 Config/testthat/edition: 3
 Encoding: UTF-8
 Language: en-US
diff --git a/R/finalize_doubles.R b/R/finalize_doubles.R
index 76cc788..5923b6f 100644
--- a/R/finalize_doubles.R
+++ b/R/finalize_doubles.R
@@ -1,11 +1,11 @@
 #' Downcast integer-valued double columns to integer
 #'
-#' Iterates over all columns in `dataset` and converts any double column whose
-#' values can all be represented as integers (as determined by
-#' `stbl::is_int_ish()`) to integer using `stbl::to_int()`. Columns that are
-#' not doubles, or that contain non-integer-valued data, are left unchanged.
+#' Iterates over all columns or elements in `dataset` and converts any double
+#' column whose values can all be represented as integers to integers. Columns
+#' that are not doubles, or that contain non-integer-valued data, are left
+#' unchanged.
 #'
-#' @param dataset (`data.frame`) The dataset to process.
+#' @param dataset (`data.frame` or `list`) The dataset to process.
 #'
 #' @returns The `dataset` with all safely-downcasted double columns converted to
 #'   integer.
@@ -15,11 +15,11 @@
 #' df <- data.frame(x = c(1.0, 2.0, 3.0), y = c(1.1, 2.2, 3.3))
 #' finalize_doubles(df)
 finalize_doubles <- function(dataset) {
-  if (!is.data.frame(dataset)) {
+  if (!is.null(dataset) && !is.list(dataset)) {
     stbl::pkg_abort(
       "datawrap",
       "{.arg dataset} must be a {.cls data.frame}.",
-      "invalid_argument"
+      c("invalid_dataset", "invalid_argument")
     )
   }
   int_ish_cols <- purrr::map_lgl(dataset, is.double) &
diff --git a/tests/testthat/test-finalize_doubles.R b/tests/testthat/test-finalize_doubles.R
index c958b01..1d9532d 100644
--- a/tests/testthat/test-finalize_doubles.R
+++ b/tests/testthat/test-finalize_doubles.R
@@ -1,5 +1,3 @@
-# finalize_doubles() -----------------------------------------------------------
-
 test_that("finalize_doubles() converts integer-valued double columns to integer (#10)", {
   df <- data.frame(x = c(1.0, 2.0, 3.0), y = c(1.1, 2.2, 3.3))
   result <- finalize_doubles(df)
@@ -7,6 +5,13 @@ test_that("finalize_doubles() converts integer-valued double columns to integer
   expect_type(result$y, "double")
 })
 
+test_that("finalize_doubles() converts integer-valued double elements in a list to integer (#10)", {
+  lst <- list(x = c(1.0, 2.0, 3.0), y = c(1.1, 2.2, 3.3))
+  result <- finalize_doubles(lst)
+  expect_type(result$x, "integer")
+  expect_type(result$y, "double")
+})
+
 test_that("finalize_doubles() leaves non-double columns unchanged (#10)", {
   df <- data.frame(
     x = c(1.0, 2.0),
@@ -34,20 +39,23 @@ test_that("finalize_doubles() preserves the class of the input (#10)", {
 
 test_that("finalize_doubles() errors if dataset is not a data.frame (#10)", {
   stbl::expect_pkg_error_classes(
-    finalize_doubles(list(x = 1.0)),
+    finalize_doubles("not a dataset"),
     "datawrap",
+    "invalid_dataset",
     "invalid_argument"
   )
 })
 
 test_that("finalize_doubles() handles a dataset with no double columns (#10)", {
   df <- data.frame(x = 1L, y = "a", stringsAsFactors = FALSE)
-  result <- finalize_doubles(df)
-  expect_identical(result, df)
+  expect_identical(finalize_doubles(df), df)
 })
 
 test_that("finalize_doubles() handles an empty data frame (#10)", {
   df <- data.frame()
-  result <- finalize_doubles(df)
-  expect_identical(result, df)
+  expect_identical(finalize_doubles(df), df)
+})
+
+test_that("finalize_doubles() handles NULL (#10)", {
+  expect_null(finalize_doubles(NULL))
 })

From 352157dd5524655d9df37cb283014ee64e469d60 Mon Sep 17 00:00:00 2001
From: Jon Harmon <jonthegeek@gmail.com>
Date: Tue, 10 Mar 2026 09:29:55 -0500
Subject: [PATCH 5/8] Rename (and reinterpret) as `finalize_integers()`.

---
 NAMESPACE                               |  2 +-
 R/finalize_doubles.R                    | 29 -----------
 R/finalize_integers.R                   | 29 +++++++++++
 man/finalize_doubles.Rd                 | 25 ---------
 man/finalize_integers.Rd                | 24 +++++++++
 tests/testthat/test-finalize_doubles.R  | 61 ----------------------
 tests/testthat/test-finalize_integers.R | 68 +++++++++++++++++++++++++
 7 files changed, 122 insertions(+), 116 deletions(-)
 delete mode 100644 R/finalize_doubles.R
 create mode 100644 R/finalize_integers.R
 delete mode 100644 man/finalize_doubles.Rd
 create mode 100644 man/finalize_integers.Rd
 delete mode 100644 tests/testthat/test-finalize_doubles.R
 create mode 100644 tests/testthat/test-finalize_integers.R

diff --git a/NAMESPACE b/NAMESPACE
index 9e71e1d..3437290 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -2,5 +2,5 @@
 
 export(create_dataset_dictionary)
 export(describe_dataset)
-export(finalize_doubles)
+export(finalize_integers)
 export(write_dataset_dictionary)
diff --git a/R/finalize_doubles.R b/R/finalize_doubles.R
deleted file mode 100644
index 5923b6f..0000000
--- a/R/finalize_doubles.R
+++ /dev/null
@@ -1,29 +0,0 @@
-#' Downcast integer-valued double columns to integer
-#'
-#' Iterates over all columns or elements in `dataset` and converts any double
-#' column whose values can all be represented as integers to integers. Columns
-#' that are not doubles, or that contain non-integer-valued data, are left
-#' unchanged.
-#'
-#' @param dataset (`data.frame` or `list`) The dataset to process.
-#'
-#' @returns The `dataset` with all safely-downcasted double columns converted to
-#'   integer.
-#' @export
-#'
-#' @examples
-#' df <- data.frame(x = c(1.0, 2.0, 3.0), y = c(1.1, 2.2, 3.3))
-#' finalize_doubles(df)
-finalize_doubles <- function(dataset) {
-  if (!is.null(dataset) && !is.list(dataset)) {
-    stbl::pkg_abort(
-      "datawrap",
-      "{.arg dataset} must be a {.cls data.frame}.",
-      c("invalid_dataset", "invalid_argument")
-    )
-  }
-  int_ish_cols <- purrr::map_lgl(dataset, is.double) &
-    purrr::map_lgl(dataset, stbl::is_int_ish)
-  dataset[int_ish_cols] <- purrr::map(dataset[int_ish_cols], stbl::to_int)
-  dataset
-}
diff --git a/R/finalize_integers.R b/R/finalize_integers.R
new file mode 100644
index 0000000..ae511e7
--- /dev/null
+++ b/R/finalize_integers.R
@@ -0,0 +1,29 @@
+#' Downcast integerish columns to integer
+#'
+#' Iterates over all columns (or list elements) in `dataset` and converts any
+#' non-logical column whose values can all be represented as integers without
+#' losing any information to integers. Columns that contain non-integerish data
+#' are left unchanged.
+#'
+#' @param dataset (`data.frame` or `list`) The dataset to process.
+#'
+#' @returns The `dataset` with all integerish columns converted to integer.
+#' @export
+#'
+#' @examples
+#' df <- data.frame(x = c(1.0, 2.0, 3.0), y = c(1.1, 2.2, 3.3))
+#' finalize_integers(df)
+finalize_integers <- function(dataset) {
+  if (!is.null(dataset) && !is.list(dataset)) {
+    stbl::pkg_abort(
+      "datawrap",
+      "{.arg dataset} must be a {.cls data.frame}.",
+      c("invalid_dataset", "invalid_argument")
+    )
+  }
+  int_ish_cols <- purrr::map_lgl(dataset, \(x) {
+    !is.logical(x) && stbl::is_int_ish(x)
+  })
+  dataset[int_ish_cols] <- purrr::map(dataset[int_ish_cols], stbl::to_int)
+  dataset
+}
diff --git a/man/finalize_doubles.Rd b/man/finalize_doubles.Rd
deleted file mode 100644
index 6293948..0000000
--- a/man/finalize_doubles.Rd
+++ /dev/null
@@ -1,25 +0,0 @@
-% Generated by roxygen2: do not edit by hand
-% Please edit documentation in R/finalize_doubles.R
-\name{finalize_doubles}
-\alias{finalize_doubles}
-\title{Downcast integer-valued double columns to integer}
-\usage{
-finalize_doubles(dataset)
-}
-\arguments{
-\item{dataset}{(\code{data.frame}) The dataset to process.}
-}
-\value{
-The \code{dataset} with all safely-downcasted double columns converted to
-integer.
-}
-\description{
-Iterates over all columns in \code{dataset} and converts any double column whose
-values can all be represented as integers (as determined by
-\code{stbl::is_int_ish()}) to integer using \code{stbl::to_int()}. Columns that are
-not doubles, or that contain non-integer-valued data, are left unchanged.
-}
-\examples{
-df <- data.frame(x = c(1.0, 2.0, 3.0), y = c(1.1, 2.2, 3.3))
-finalize_doubles(df)
-}
diff --git a/man/finalize_integers.Rd b/man/finalize_integers.Rd
new file mode 100644
index 0000000..9612c35
--- /dev/null
+++ b/man/finalize_integers.Rd
@@ -0,0 +1,24 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/finalize_integers.R
+\name{finalize_integers}
+\alias{finalize_integers}
+\title{Downcast integerish columns to integer}
+\usage{
+finalize_integers(dataset)
+}
+\arguments{
+\item{dataset}{(\code{data.frame} or \code{list}) The dataset to process.}
+}
+\value{
+The \code{dataset} with all integerish columns converted to integer.
+}
+\description{
+Iterates over all columns (or list elements) in \code{dataset} and converts any
+non-logical column whose values can all be represented as integers without
+losing any information to integers. Columns that contain non-integerish data
+are left unchanged.
+}
+\examples{
+df <- data.frame(x = c(1.0, 2.0, 3.0), y = c(1.1, 2.2, 3.3))
+finalize_integers(df)
+}
diff --git a/tests/testthat/test-finalize_doubles.R b/tests/testthat/test-finalize_doubles.R
deleted file mode 100644
index 1d9532d..0000000
--- a/tests/testthat/test-finalize_doubles.R
+++ /dev/null
@@ -1,61 +0,0 @@
-test_that("finalize_doubles() converts integer-valued double columns to integer (#10)", {
-  df <- data.frame(x = c(1.0, 2.0, 3.0), y = c(1.1, 2.2, 3.3))
-  result <- finalize_doubles(df)
-  expect_type(result$x, "integer")
-  expect_type(result$y, "double")
-})
-
-test_that("finalize_doubles() converts integer-valued double elements in a list to integer (#10)", {
-  lst <- list(x = c(1.0, 2.0, 3.0), y = c(1.1, 2.2, 3.3))
-  result <- finalize_doubles(lst)
-  expect_type(result$x, "integer")
-  expect_type(result$y, "double")
-})
-
-test_that("finalize_doubles() leaves non-double columns unchanged (#10)", {
-  df <- data.frame(
-    x = c(1.0, 2.0),
-    y = letters[1:2],
-    z = TRUE,
-    stringsAsFactors = FALSE
-  )
-  result <- finalize_doubles(df)
-  expect_type(result$y, "character")
-  expect_type(result$z, "logical")
-})
-
-test_that("finalize_doubles() preserves NA values in converted columns (#10)", {
-  df <- data.frame(x = c(1.0, NA, 3.0))
-  result <- finalize_doubles(df)
-  expect_type(result$x, "integer")
-  expect_true(is.na(result$x[[2]]))
-})
-
-test_that("finalize_doubles() preserves the class of the input (#10)", {
-  tbl <- tibble::tibble(x = c(1.0, 2.0))
-  result <- finalize_doubles(tbl)
-  expect_identical(class(result), class(tbl))
-})
-
-test_that("finalize_doubles() errors if dataset is not a data.frame (#10)", {
-  stbl::expect_pkg_error_classes(
-    finalize_doubles("not a dataset"),
-    "datawrap",
-    "invalid_dataset",
-    "invalid_argument"
-  )
-})
-
-test_that("finalize_doubles() handles a dataset with no double columns (#10)", {
-  df <- data.frame(x = 1L, y = "a", stringsAsFactors = FALSE)
-  expect_identical(finalize_doubles(df), df)
-})
-
-test_that("finalize_doubles() handles an empty data frame (#10)", {
-  df <- data.frame()
-  expect_identical(finalize_doubles(df), df)
-})
-
-test_that("finalize_doubles() handles NULL (#10)", {
-  expect_null(finalize_doubles(NULL))
-})
diff --git a/tests/testthat/test-finalize_integers.R b/tests/testthat/test-finalize_integers.R
new file mode 100644
index 0000000..3a20e97
--- /dev/null
+++ b/tests/testthat/test-finalize_integers.R
@@ -0,0 +1,68 @@
+test_that("finalize_integers() converts integerish double columns to integer (#10)", {
+  df <- data.frame(x = c(1.0, 2.0, 3.0), y = c(1.1, 2.2, 3.3))
+  result <- finalize_integers(df)
+  expect_type(result$x, "integer")
+  expect_type(result$y, "double")
+})
+
+test_that("finalize_integers() converts integer-valued double elements in a list to integer (#10)", {
+  lst <- list(x = c(1.0, 2.0, 3.0), y = c(1.1, 2.2, 3.3))
+  result <- finalize_integers(lst)
+  expect_type(result$x, "integer")
+  expect_type(result$y, "double")
+})
+
+test_that("finalize_integers() converts integerish character columns to integer (#10)", {
+  df <- data.frame(x = as.character(1:3), y = as.character(c(1.1, 2.2, 3.3)))
+  result <- finalize_integers(df)
+  expect_type(result$x, "integer")
+  expect_type(result$y, "character")
+})
+
+test_that("finalize_integers() leaves non-integerish columns unchanged (#10)", {
+  df <- data.frame(
+    x = c(1.0, 2.0),
+    y = letters[1:2],
+    z = TRUE,
+    stringsAsFactors = FALSE
+  )
+  result <- finalize_integers(df)
+  expect_type(result$y, "character")
+  expect_type(result$z, "logical")
+})
+
+test_that("finalize_integers() preserves NA values in converted columns (#10)", {
+  df <- data.frame(x = c(1.0, NA, 3.0))
+  result <- finalize_integers(df)
+  expect_type(result$x, "integer")
+  expect_true(is.na(result$x[[2]]))
+})
+
+test_that("finalize_integers() preserves the class of the input (#10)", {
+  tbl <- tibble::tibble(x = c(1.0, 2.0))
+  result <- finalize_integers(tbl)
+  expect_identical(class(result), class(tbl))
+})
+
+test_that("finalize_integers() errors if dataset is not a data.frame or list (#10)", {
+  stbl::expect_pkg_error_classes(
+    finalize_integers("not a dataset"),
+    "datawrap",
+    "invalid_dataset",
+    "invalid_argument"
+  )
+})
+
+test_that("finalize_integers() handles a dataset with no double columns (#10)", {
+  df <- data.frame(x = 1L, y = "a", stringsAsFactors = FALSE)
+  expect_identical(finalize_integers(df), df)
+})
+
+test_that("finalize_integers() handles an empty data frame (#10)", {
+  df <- data.frame()
+  expect_identical(finalize_integers(df), df)
+})
+
+test_that("finalize_integers() handles NULL (#10)", {
+  expect_null(finalize_integers(NULL))
+})

From 564b2c780a769be37cd1a574cd9d5cc10485c51a Mon Sep 17 00:00:00 2001
From: Jon Harmon <jonthegeek@gmail.com>
Date: Tue, 10 Mar 2026 09:35:31 -0500
Subject: [PATCH 6/8] Make R CMD check happy about `NEWS.md`

---
 DESCRIPTION | 4 +++-
 NEWS.md     | 7 +++++--
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/DESCRIPTION b/DESCRIPTION
index 5bce19f..083fc22 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,6 +1,6 @@
 Package: datawrap
 Title: Final Steps for Dataset Preparation
-Version: 0.0.0.9000
+Version: 0.0.0.9001
 Authors@R: 
     person("Jon", "Harmon", , "jonthegeek@gmail.com", role = c("aut", "cre"),
            comment = c(ORCID = "0000-0003-4781-4346"))
@@ -10,6 +10,8 @@ License: MIT + file LICENSE
 URL: https://wranglezone.github.io/datawrap/,
     https://github.com/wranglezone/datawrap
 BugReports: https://github.com/wranglezone/datawrap/issues
+Depends:
+    R (>= 4.1)
 Imports:
     knitr,
     purrr,
diff --git a/NEWS.md b/NEWS.md
index 3ea0dfc..d68d0da 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,4 +1,7 @@
 # datawrap (development version)
 
-* `finalize_doubles()` converts integer-valued double columns to integer for
-  efficient storage (@copilot, #10).
+* `finalize_integers()` converts integerish columns to integer for efficient storage (@copilot, #10).
+
+# datawrap 0.0.0.9000
+
+* Initial release.

From 1e0e897024333e346d992d104a342b95c3d60c8b Mon Sep 17 00:00:00 2001
From: Jon Harmon <jonthegeek@gmail.com>
Date: Tue, 10 Mar 2026 09:37:38 -0500
Subject: [PATCH 7/8] Add refactor TODO.

---
 R/finalize_integers.R | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/R/finalize_integers.R b/R/finalize_integers.R
index ae511e7..36181a5 100644
--- a/R/finalize_integers.R
+++ b/R/finalize_integers.R
@@ -21,6 +21,9 @@ finalize_integers <- function(dataset) {
       c("invalid_dataset", "invalid_argument")
     )
   }
+  # TODO: This function isn't enough to warrant adding dplyr to imports, but
+  # this should be refactored to use dplyr::mutate, dplyr::across, and
+  # dplyr::where when something else necessitates dplyr.
   int_ish_cols <- purrr::map_lgl(dataset, \(x) {
     !is.logical(x) && stbl::is_int_ish(x)
   })

From fffb1c7cedbff3bf0fb0cd27b5f448b3875212dc Mon Sep 17 00:00:00 2001
From: Jon Harmon <jonthegeek@gmail.com>
Date: Tue, 10 Mar 2026 09:52:31 -0500
Subject: [PATCH 8/8] Apply copilot review suggestions

---
 NEWS.md                                 |  2 +-
 R/finalize_integers.R                   | 13 +++++++------
 man/finalize_integers.Rd                |  5 +++--
 tests/testthat/test-finalize_integers.R |  2 +-
 4 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/NEWS.md b/NEWS.md
index d68d0da..729911f 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,6 +1,6 @@
 # datawrap (development version)
 
-* `finalize_integers()` converts integerish columns to integer for efficient storage (@copilot, #10).
+* `finalize_integers()` converts integerish columns to integer for efficient storage (@copilot & @jonthegeek, #10).
 
 # datawrap 0.0.0.9000
 
diff --git a/R/finalize_integers.R b/R/finalize_integers.R
index 36181a5..0d2940c 100644
--- a/R/finalize_integers.R
+++ b/R/finalize_integers.R
@@ -5,9 +5,10 @@
 #' losing any information to integers. Columns that contain non-integerish data
 #' are left unchanged.
 #'
-#' @param dataset (`data.frame` or `list`) The dataset to process.
+#' @param dataset (`data.frame`, `list`, or `NULL`) The dataset to process.
 #'
-#' @returns The `dataset` with all integerish columns converted to integer.
+#' @returns The `dataset` with all integerish columns converted to integer (or
+#'   `NULL` if `dataset` is `NULL`).
 #' @export
 #'
 #' @examples
@@ -17,13 +18,13 @@ finalize_integers <- function(dataset) {
   if (!is.null(dataset) && !is.list(dataset)) {
     stbl::pkg_abort(
       "datawrap",
-      "{.arg dataset} must be a {.cls data.frame}.",
+      "{.arg dataset} must be a {.cls data.frame}, {.cls list}, or {.cls NULL}.",
       c("invalid_dataset", "invalid_argument")
     )
   }
-  # TODO: This function isn't enough to warrant adding dplyr to imports, but
-  # this should be refactored to use dplyr::mutate, dplyr::across, and
-  # dplyr::where when something else necessitates dplyr.
+  # NOTE: This function alone does not warrant adding dplyr to imports, but it
+  # could be refactored to use dplyr::mutate, dplyr::across, and dplyr::where
+  # if dplyr is added as a dependency elsewhere in the package.
   int_ish_cols <- purrr::map_lgl(dataset, \(x) {
     !is.logical(x) && stbl::is_int_ish(x)
   })
diff --git a/man/finalize_integers.Rd b/man/finalize_integers.Rd
index 9612c35..c34f33a 100644
--- a/man/finalize_integers.Rd
+++ b/man/finalize_integers.Rd
@@ -7,10 +7,11 @@
 finalize_integers(dataset)
 }
 \arguments{
-\item{dataset}{(\code{data.frame} or \code{list}) The dataset to process.}
+\item{dataset}{(\code{data.frame}, \code{list}, or \code{NULL}) The dataset to process.}
 }
 \value{
-The \code{dataset} with all integerish columns converted to integer.
+The \code{dataset} with all integerish columns converted to integer (or
+\code{NULL} if \code{dataset} is \code{NULL}).
 }
 \description{
 Iterates over all columns (or list elements) in \code{dataset} and converts any
diff --git a/tests/testthat/test-finalize_integers.R b/tests/testthat/test-finalize_integers.R
index 3a20e97..2f4e4ad 100644
--- a/tests/testthat/test-finalize_integers.R
+++ b/tests/testthat/test-finalize_integers.R
@@ -44,7 +44,7 @@ test_that("finalize_integers() preserves the class of the input (#10)", {
   expect_identical(class(result), class(tbl))
 })
 
-test_that("finalize_integers() errors if dataset is not a data.frame or list (#10)", {
+test_that("finalize_integers() errors if dataset is not a data.frame, list, or NULL (#10)", {
   stbl::expect_pkg_error_classes(
     finalize_integers("not a dataset"),
     "datawrap",