diff --git a/.github/workflows/pr_title.yml b/.github/workflows/pr_title.yml
new file mode 100644
index 0000000..553db64
--- /dev/null
+++ b/.github/workflows/pr_title.yml
@@ -0,0 +1,20 @@
+name: 'PR Title Checker'
+on:
+  pull_request:
+    types: [edited, opened, synchronize, reopened]
+    branches:
+    - main
+    - master
+
+jobs:
+  title-check:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: naveenk1223/action-pr-title@master
+        with:
+          regex: 'Version [0-9]+\.[0-9]+(\.[0-9]+)?$' # Regex the title should match.
+          allowed_prefixes: ':bookmark:' # title should start with the given prefix
+          prefix_case_sensitive: true # title prefix are case insensitive
+          min_length: 11 # Min length of the title
+          max_length: -1 # Max length of the title
+          name: Check PR title
diff --git a/.zenodo.json b/.zenodo.json
index 9191de3..01e42a1 100644
--- a/.zenodo.json
+++ b/.zenodo.json
@@ -1,6 +1,6 @@
 {
   "title": "git2rdata: Store and Retrieve Data.frames in a Git Repository",
-  "version": "0.4.1",
+  "version": "0.5.0",
   "license": "GPL-3.0",
   "upload_type": "software",
   "description": "<p>The git2rdata package is an R package for writing and reading dataframes as plain text files. A metadata file stores important information. 1) Storing metadata allows to maintain the classes of variables. By default, git2rdata optimizes the data for file storage. The optimization is most effective on data containing factors. The optimization makes the data less human readable. The user can turn this off when they prefer a human readable format over smaller files. Details on the implementation are available in vignette(“plain_text”, package = “git2rdata”). 2) Storing metadata also allows smaller row based diffs between two consecutive commits. This is a useful feature when storing data as plain text files under version control. Details on this part of the implementation are available in vignette(“version_control”, package = “git2rdata”). Although we envisioned git2rdata with a git workflow in mind, you can use it in combination with other version control systems like subversion or mercurial. 3) git2rdata is a useful tool in a reproducible and traceable workflow. vignette(“workflow”, package = “git2rdata”) gives a toy example. 4) vignette(“efficiency”, package = “git2rdata”) provides some insight into the efficiency of file storage, git repository size and speed for writing and reading.<\/p>",
diff --git a/CITATION.cff b/CITATION.cff
index 9afa3b0..9dbf321 100644
--- a/CITATION.cff
+++ b/CITATION.cff
@@ -40,4 +40,4 @@ identifiers:
   value: 10.5281/zenodo.1485309
 - type: url
   value: https://ropensci.github.io/git2rdata/
-version: 0.4.1
+version: 0.5.0
diff --git a/DESCRIPTION b/DESCRIPTION
index 50f863d..5eb3554 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,6 +1,6 @@
 Package: git2rdata
 Title: Store and Retrieve Data.frames in a Git Repository
-Version: 0.4.1
+Version: 0.5.0
 Authors@R: c(
     person("Thierry", "Onkelinx", , "thierry.onkelinx@inbo.be", role = c("aut", "cre"),
            comment = c(ORCID = "0000-0001-8804-4216", affiliation = "Research Institute for Nature and Forest (INBO)")),
@@ -38,7 +38,7 @@ URL: https://ropensci.github.io/git2rdata/,
     https://doi.org/10.5281/zenodo.1485309
 BugReports: https://github.com/ropensci/git2rdata/issues
 Depends: 
-    R (>= 3.5.0)
+    R (>= 4.1.0)
 Imports:
     assertthat,
     git2r (>= 0.23.0),
@@ -46,6 +46,7 @@ Imports:
     yaml
 Suggests:
     ggplot2,
+    jsonlite,
     knitr,
     microbenchmark,
     rmarkdown,
@@ -60,6 +61,7 @@ Roxygen: list(markdown = TRUE)
 RoxygenNote: 7.3.2
 Collate:
     'clean_data_path.R'
+    'data_package.R'
     'datahash.R'
     'display_metadata.R'
     'git2rdata_package.R'
diff --git a/NAMESPACE b/NAMESPACE
index 7371ab5..0778fdc 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -51,6 +51,7 @@ S3method(write_vc,character)
 S3method(write_vc,default)
 S3method(write_vc,git_repository)
 export(commit)
+export(data_package)
 export(display_metadata)
 export(is_git2rdata)
 export(is_git2rmeta)
@@ -74,6 +75,7 @@ importFrom(assertthat,"on_failure<-")
 importFrom(assertthat,assert_that)
 importFrom(assertthat,has_attr)
 importFrom(assertthat,has_name)
+importFrom(assertthat,is.count)
 importFrom(assertthat,is.flag)
 importFrom(assertthat,is.string)
 importFrom(assertthat,noNA)
diff --git a/NEWS.md b/NEWS.md
index f8a08c0..2346424 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,3 +1,10 @@
+# git2rdata 0.5.0
+
+* `read_vc()` handles empty datasets stored with `split_by`. 
+* `write_vc()` and `meta()` gain a `digits` argument.
+  The arguments specifies the number of significant digits to store for numeric
+  values.
+
 # git2rdata 0.4.1
 
 * Add `update_metadata()` to update the description of a `git2rdata` object.
diff --git a/R/data_package.R b/R/data_package.R
new file mode 100644
index 0000000..a170105
--- /dev/null
+++ b/R/data_package.R
@@ -0,0 +1,107 @@
+#' Create a Data Package for a directory of CSV files
+#'
+#' @description
+#' Create a `datapackage.json` file for a directory of CSV files.
+#' The function will look for all `.csv` files in the directory and its
+#' subdirectories.
+#' It will then create a `datapackage.json` file with the metadata of each CSV
+#' file.
+#'
+#' @param path the directory in which to create the `datapackage.json` file.
+#' @family storage
+#' @export
+#' @importFrom assertthat assert_that is.string noNA
+data_package <- function(path = ".") {
+  assert_that(
+    is.string(path), noNA(path), requireNamespace("jsonlite", quietly = TRUE)
+  )
+  stopifnot("`path` is not a directory" = file_test("-d", path))
+
+  data_files <- list.files(path, pattern = ".csv$", recursive = TRUE)
+  relevant <- vapply(
+    data_files, FUN = is_git2rdata, FUN.VALUE = logical(1), root = path
+  )
+  stopifnot(
+    "no non-optimized git2rdata objects found at `path`" = any(relevant)
+  )
+  data_files <- data_files[relevant]
+
+  list(
+    resources = vapply(
+        data_files, path = path, FUN = data_resource,
+        FUN.VALUE = vector(mode = "list", length = 1)
+      ) |>
+        unname()
+  ) |>
+    jsonlite::toJSON(pretty = TRUE, auto_unbox = TRUE) |>
+    writeLines(file.path(path, "datapackage.json"))
+  return(file.path(path, "datapackage.json"))
+}
+
+#' @importFrom assertthat assert_that is.string noNA
+#' @importFrom yaml read_yaml
+data_resource <- function(file, path = ".") {
+  assert_that(
+    is.string(file), is.string(path), noNA(file), noNA(path)
+  )
+  stopifnot("`path` is not a directory" = file_test("-d", path))
+
+  clean_data_path(root = path, file = file)[2] |>
+    read_yaml() -> metadata
+  list(
+    name = coalesce(metadata[["..generic"]][["name"]], file), path = file,
+    "encoding" = "utf-8", format = "csv", media_type = "text/csv",
+    hash = paste0("sha1:", metadata[["..generic"]][["data_hash"]]),
+    schema = list(
+      fields = vapply(
+        names(metadata)[-1], metadata = metadata, FUN = field_schema,
+        FUN.VALUE = vector(mode = "list", length = 1)
+      ) |>
+        unname(),
+      missingValues = list(
+        c(value = metadata[["..generic"]][["NA string"]], label = "missing")
+      )
+    )
+  ) -> dr
+  extra <- c("title", "description")
+  metadata[["..generic"]][extra[extra %in% names(metadata[["..generic"]])]] |>
+    c(dr) |>
+    list()
+}
+
+field_schema <- function(x, metadata) {
+  switch(
+    metadata[[x]]$class,
+    "character" = list(name = x, type = "string"),
+    "Date" = list(name = x, type = "date"),
+    "logical" = list(
+      name = x, type = "boolean", trueValues = c("TRUE", "true"),
+      falseValues = c("FALSE", "false")
+    ),
+    "factor" = list(
+      name = x, type = "string", categories = metadata[[x]][["labels"]],
+      categoriesOrdered = metadata[[x]][["ordered"]]
+    ),
+    "integer" = list(name = x, type = "integer"),
+    "numeric" = list(name = x, type = "number"),
+    "POSIXct" = list(
+      name = x, type = "datetime", format = "%Y-%m-%dT%H:%M:%SZ"
+    ),
+    stop("field_schema() can't handle ", metadata[[x]]$class)
+  ) -> fs
+  if ("description" %in% names(metadata[[x]])) {
+    fs$description <- metadata[[x]][["description"]]
+  }
+  return(list(fs))
+}
+
+coalesce <- function(...) {
+  dots <- list(...)
+  if (length(dots) == 0) {
+    return(NULL)
+  }
+  if (!is.null(dots[[1]])) {
+    return(dots[[1]])
+  }
+  do.call(coalesce, dots[-1])
+}
diff --git a/R/meta.R b/R/meta.R
index 22483df..6ee9bfd 100644
--- a/R/meta.R
+++ b/R/meta.R
@@ -14,7 +14,7 @@
 #' @examples
 #' meta(c(NA, "'NA'", '"NA"', "abc\tdef", "abc\ndef"))
 #' meta(1:3)
-#' meta(seq(1, 3, length = 4))
+#' meta(seq(1, 3, length = 4), digits = 6)
 #' meta(factor(c("b", NA, "NA"), levels = c("NA", "b", "c")))
 #' meta(factor(c("b", NA, "a"), levels = c("a", "b", "c")), optimize = FALSE)
 #' meta(factor(c("b", NA, "a"), levels = c("a", "b", "c"), ordered = TRUE))
@@ -29,7 +29,7 @@
 #' meta(as.POSIXct("2019-02-01 10:59:59", tz = "CET"), optimize = FALSE)
 #' meta(as.Date("2019-02-01"))
 #' meta(as.Date("2019-02-01"), optimize = FALSE)
-meta <- function(x, ...) {
+meta <- function(x, ..., digits) {
   UseMethod("meta", x)
 }
 
@@ -63,8 +63,11 @@ meta.integer <- function(x, ...) {
 }
 
 #' @export
-meta.numeric <- function(x, ...) {
-  list(class = "numeric") -> m
+#' @importFrom assertthat assert_that is.count
+meta.numeric <- function(x, ..., digits) {
+  stopifnot("`digits` must be a strict positive integer" = is.count(digits))
+  x <- signif(x, digits = digits)
+  list(class = "numeric", digits = as.integer(digits)) -> m
   class(m) <- "meta_detail"
   attr(x, "meta") <- m
   return(x)
@@ -218,7 +221,7 @@ meta.Date <- function(x, optimize = TRUE, ...) {
 #' @inheritParams write_vc
 meta.data.frame <- function(# nolint
   x, optimize = TRUE, na = "NA", sorting, strict = TRUE,
-  split_by = character(0), ...
+  split_by = character(0), ..., digits
 ) {
   assert_that(
     !has_name(x, "..generic"),
@@ -237,13 +240,46 @@ meta.data.frame <- function(# nolint
   )
 
   dots <- list(...)
+  float <- vapply(x, is.numeric, logical(1)) &
+    !vapply(x, is.integer, logical(1))
   if (has_name(dots, "old")) {
     old <- dots$old
     assert_that(inherits(old, "meta_list"))
     if (missing(sorting)) {
       sorting <- old[["..generic"]][["sorting"]]
     }
+    if (any(float) && missing(digits)) {
+      old_numeric <- vapply(
+        old, FUN.VALUE = logical(1),
+        FUN = function(x) {
+          has_name(x, "class") && x$class == "numeric" && has_name(x, "digits")
+        }
+      )
+      digits <- vapply(
+        old[old_numeric], FUN.VALUE = numeric(1),
+        FUN = function(x) {
+          x[["digits"]]
+        }
+      )
+      relevant <- names(float)[float][!names(float)[float] %in% names(digits)]
+      rep(6L, length(relevant)) -> digits[relevant]
+    }
+  }
+  if (any(float) && missing(digits)) {
+    digits <- 6L
+    warning("`digits` was not set. Setting is automatically to 6. See ?meta")
   }
+  if (any(float) && is.null(names(digits))) {
+    stopifnot(
+      "`digits` must be either named or have length 1" = length(digits) == 1
+    )
+    digits <- rep(digits, sum(float))
+    names(digits) <- names(float)[float]
+  }
+  stopifnot(
+    "`digits` must contain all numeric variables of `x`" =
+      all(!float) || all(names(float)[float] %in% names(digits))
+  )
 
   # apply sorting
   if (missing(sorting) || is.null(sorting) || !length(sorting)) {
@@ -271,12 +307,13 @@ Add extra sorting variables to ensure small diffs.", sorted)
   if (length(split_by) > 0) {
     generic <- c(generic, split_by = list(split_by))
   }
+
   # calculate meta for each column
   if (!has_name(dots, "old")) {
     z <- lapply(
       colnames(x),
       function(id, optimize, na) {
-        meta(x[[id]], optimize = optimize, na = na)
+        meta(x[[id]], optimize = optimize, na = na, digits = digits[[id]])
       },
       optimize = optimize, na = na
     )
@@ -290,7 +327,7 @@ Add extra sorting variables to ensure small diffs.", sorted)
           meta(
             x[[id]], optimize = optimize, na = na,
             index = setNames(old[[id]][["index"]], old[[id]][["labels"]]),
-            strict = strict
+            strict = strict, digits = digits[[id]]
           )
         },
         optimize = old[["..generic"]][["optimize"]],
@@ -305,7 +342,7 @@ Add extra sorting variables to ensure small diffs.", sorted)
       z_new <- lapply(
         new,
         function(id, optimize, na) {
-          meta(x[[id]], optimize = optimize, na = na)
+          meta(x[[id]], optimize = optimize, na = na, digits = digits[[id]])
         },
         optimize = optimize, na = na
       )
diff --git a/R/read_vc.R b/R/read_vc.R
index 2c57d41..ddd346d 100644
--- a/R/read_vc.R
+++ b/R/read_vc.R
@@ -83,29 +83,38 @@ read_vc.character <- function(file, root = ".") {
       comment.char = "",
       stringsAsFactors = FALSE, fileEncoding = "UTF-8"
     )
-    raw_data <- vapply(
-      seq_len(nrow(index)),
-      function(i) {
-        rf <- file.path(file["raw_file"], paste0(index[i, "..hash"], ".tsv"))
-        raw_data <- read.table(
-          file = rf, header = TRUE, sep = "\t", quote = "\"",
-          dec = ".", numerals = "warn.loss", na.strings = na_string,
-          colClasses = setNames(
-            col_type[col_classes[!which_split_by]],
-            col_names[!which_split_by]
-          ),
-          comment.char = "",
-          stringsAsFactors = FALSE, fileEncoding = "UTF-8"
-        )
-        raw_data <- cbind(
-          index[rep(i, nrow(raw_data)), split_by, drop = FALSE],
-          raw_data
-        )
-        return(list(raw_data))
-      },
-      vector(mode = "list", length = 1)
-    )
-    raw_data <- do.call(rbind, raw_data)[, col_names]
+    if (nrow(index) == 0) {
+      list(
+        character = character(0), factor = character(0), integer = integer(0),
+        numeric = numeric(0)
+      )[col_classes] |>
+        setNames(col_names) |>
+        as.data.frame() -> raw_data
+    } else {
+      raw_data <- vapply(
+        seq_len(nrow(index)),
+        function(i) {
+          rf <- file.path(file["raw_file"], paste0(index[i, "..hash"], ".tsv"))
+          raw_data <- read.table(
+            file = rf, header = TRUE, sep = "\t", quote = "\"",
+            dec = ".", numerals = "warn.loss", na.strings = na_string,
+            colClasses = setNames(
+              col_type[col_classes[!which_split_by]],
+              col_names[!which_split_by]
+            ),
+            comment.char = "",
+            stringsAsFactors = FALSE, fileEncoding = "UTF-8"
+          )
+          raw_data <- cbind(
+            index[rep(i, nrow(raw_data)), split_by, drop = FALSE],
+            raw_data
+          )
+          return(list(raw_data))
+        },
+        vector(mode = "list", length = 1)
+      )
+      raw_data <- do.call(rbind, raw_data)[, col_names]
+    }
   } else {
     raw_data <- read.table(
       file = file["raw_file"], header = TRUE, sep = ifelse(optimize, "\t", ","),
diff --git a/R/recent_commit.R b/R/recent_commit.R
index 81a05b2..304e9af 100644
--- a/R/recent_commit.R
+++ b/R/recent_commit.R
@@ -28,15 +28,19 @@
 #'
 #' # write and commit a first dataframe
 #' # store the output of write_vc() minimize screen output
-#' junk <- write_vc(iris[1:6, ], "iris", repo, sorting = "Sepal.Length",
-#'                  stage = TRUE)
+#' junk <- write_vc(
+#'   iris[1:6, ], "iris", repo, sorting = "Sepal.Length", stage = TRUE,
+#'   digits = 6
+#' )
 #' commit(repo, "important analysis", session = TRUE)
 #' list.files(repo_path)
 #' Sys.sleep(1.1) # required because git doesn't handle subsecond timings
 #'
 #' # write and commit a second dataframe
-#' junk <- write_vc(iris[7:12, ], "iris2", repo, sorting = "Sepal.Length",
-#'                  stage = TRUE)
+#' junk <- write_vc(
+#'   iris[7:12, ], "iris2", repo, sorting = "Sepal.Length", stage = TRUE,
+#'   digits = 6
+#' )
 #' commit(repo, "important analysis", session = TRUE)
 #' list.files(repo_path)
 #' Sys.sleep(1.1) # required because git doesn't handle subsecond timings
diff --git a/R/update_metadata.R b/R/update_metadata.R
index f09b6bb..dacd5a6 100644
--- a/R/update_metadata.R
+++ b/R/update_metadata.R
@@ -13,35 +13,46 @@
 #' @param name a character string with the new table name of the object.
 #' @param title a character string with the new title of the object.
 #' @param description a character string with the new description of the object.
+#' @param ... parameters used in some methods
 #' @family storage
 #' @export
 #' @importFrom assertthat assert_that has_name
 update_metadata <- function(
-  file, root = ".", field_description, name, title, description
+  file, root = ".", field_description, name, title, description, ...
 ) {
   UseMethod("update_metadata", root)
 }
 
 #' @export
 update_metadata.default <- function(
-  file, root = ".", field_description, name, title, description
+  file, root = ".", field_description, name, title, description, ...
 ) {
   stop("a 'root' of class ", class(root), " is not supported", call. = FALSE)
 }
 
 #' @export
+#' @importFrom assertthat assert_that is.string noNA
+#' @importFrom git2r add
+#' @inheritParams git2r::add
 update_metadata.git_repository <- function(
-    file, root = ".", field_description, name, title, description
+  file, root = ".", field_description, name, title, description, ...,
+  stage = FALSE, force = FALSE
 ) {
-  update_metadata(
+  assert_that(is.flag(stage), is.flag(force), noNA(stage), noNA(force))
+  file <- update_metadata(
     file = file, root = workdir(root), name = name, title = title,
     description = description, field_description = field_description
   )
+  if (!stage) {
+    return(invisible(file))
+  }
+  add(root, path = file, force = force)
+  return(invisible(file))
 }
 
 #' @export
 update_metadata.character <- function(
-  file, root = ".", field_description, name, title, description
+  file, root = ".", field_description, name, title, description, ...
 ) {
   root <- normalizePath(root, winslash = "/", mustWork = TRUE)
   file <- clean_data_path(root = root, file = file)
@@ -83,7 +94,7 @@ update_metadata.character <- function(
     as.character() -> old[["..generic"]][["git2rdata"]]
   metadata_hash(old) -> old[["..generic"]][["hash"]]
   write_yaml(old, file["meta_file"])
-  return(invisible(NULL))
+  return(invisible(file["meta_file"]))
 }
 
 #' @importFrom assertthat assert_that is.string
diff --git a/R/upgrade_data.R b/R/upgrade_data.R
index f35e1ab..d0a8c79 100644
--- a/R/upgrade_data.R
+++ b/R/upgrade_data.R
@@ -18,9 +18,14 @@
 #' dir.create(root)
 #'
 #' # write dataframes to the root
-#' write_vc(iris[1:6, ], file = "iris", root = root, sorting = "Sepal.Length")
-#' write_vc(iris[5:10, ], file = "subdir/iris", root = root,
-#'          sorting = "Sepal.Length")
+#' write_vc(
+#'   iris[1:6, ], file = "iris", root = root, sorting = "Sepal.Length",
+#'   digits = 6
+#' )
+#' write_vc(
+#'   iris[5:10, ], file = "subdir/iris", root = root, sorting = "Sepal.Length",
+#'   digits = 6
+#' )
 #' # upgrade a single git2rdata object
 #' upgrade_data(file = "iris", root = root)
 #' # use path = "." to upgrade all git2rdata objects under root
diff --git a/R/write_vc.R b/R/write_vc.R
index 50715ec..0175737 100644
--- a/R/write_vc.R
+++ b/R/write_vc.R
@@ -51,6 +51,13 @@ write_vc.default <- function(
 #' @param split_by An optional vector of variables name to split the text files.
 #' This creates a separate file for every combination.
 #' We prepend these variables to the vector of `sorting` variables.
+#' @param digits The number of significant digits of the smallest absolute
+#' value.
+#' The function applies the rounding automatically.
+#' Only relevant for numeric variables.
+#' Either a single positive integer or a named vector where the names link to
+#' the variables in the `data.frame`.
+#' Defaults to `6` with a warning.
 #' @export
 #' @importFrom assertthat assert_that is.string is.flag
 #' @importFrom yaml read_yaml write_yaml
@@ -58,12 +65,16 @@ write_vc.default <- function(
 #' @importFrom git2r hash
 write_vc.character <- function(
   x, file, root = ".", sorting, strict = TRUE, optimize = TRUE,
-  na = "NA", ..., split_by = character(0)
+  na = "NA", ..., append = FALSE, split_by = character(0), digits
 ) {
   assert_that(
-    inherits(x, "data.frame"), is.string(file), is.string(root),  is.string(na),
-    noNA(na), no_whitespace(na), is.flag(strict), is.flag(optimize)
+    inherits(x, "data.frame"), is.string(file), is.string(root), is.string(na),
+    noNA(na), no_whitespace(na), is.flag(strict), is.flag(optimize),
+    is.flag(append), noNA(append), noNA(strict), noNA(optimize)
   )
+  if (append) {
+    x <- append_df(x = x, file = file, root = root)
+  }
   root <- normalizePath(root, winslash = "/", mustWork = TRUE)
   file <- clean_data_path(root = root, file = file)
   if (!file.exists(dirname(file["raw_file"]))) {
@@ -72,7 +83,8 @@ write_vc.character <- function(
 
   if (!file.exists(file["meta_file"])) {
     raw_data <- meta(
-      x, optimize = optimize, na = na, sorting = sorting, split_by = split_by
+      x, optimize = optimize, na = na, sorting = sorting, split_by = split_by,
+      digits = digits
     )
   } else {
     tryCatch(
@@ -87,7 +99,7 @@ write_vc.character <- function(
     class(old) <- "meta_list"
     raw_data <- meta(
       x, optimize = optimize, na = na, sorting = sorting, old = old,
-      strict = strict, split_by = split_by
+      strict = strict, split_by = split_by, digits = digits
     )
     problems <- compare_meta(attr(raw_data, "meta"), old)
     if (length(problems)) {
@@ -184,12 +196,12 @@ setOldClass("git_repository")
 #' @inheritParams git2r::add
 #' @export
 #' @importFrom git2r workdir add
-#' @importFrom assertthat assert_that is.flag
+#' @importFrom assertthat assert_that is.flag noNA
 write_vc.git_repository <- function(
   x, file, root, sorting, strict = TRUE, optimize = TRUE, na = "NA", ...,
   stage = FALSE, force = FALSE
 ) {
-  assert_that(is.flag(stage), is.flag(force))
+  assert_that(is.flag(stage), is.flag(force), noNA(stage), noNA(force))
   hashes <- write_vc(
     x = x, file = file, root = workdir(root), sorting = sorting,
     strict = strict, optimize = optimize, na = na, ...
@@ -331,3 +343,13 @@ remove_root <- function(file, root) {
   file[has_root] <- substr(file[has_root], n_root + 1, nchar(file[has_root]))
   return(file)
 }
+
+#' @importFrom assertthat assert_that
+append_df <- function(x, file, root) {
+  assert_that(inherits(x, "data.frame"))
+  if (!is_git2rdata(file = file, root = root, message = "none")) {
+    return(x)
+  }
+  read_vc(file = file, root = root) |>
+    rbind(x)
+}
diff --git a/inst/CITATION b/inst/CITATION
index 03d5c32..ab4419e 100644
--- a/inst/CITATION
+++ b/inst/CITATION
@@ -2,12 +2,12 @@ citHeader("To cite `git2rdata` in publications please use:")
 # begin checklist entry
 bibentry(
   bibtype = "Manual",
-  title = "git2rdata: Store and Retrieve Data.frames in a Git Repository. Version 0.4.1",
+  title = "git2rdata: Store and Retrieve Data.frames in a Git Repository. Version 0.5.0",
   author = c( author = c(person(given = "Thierry", family = "Onkelinx"))),
-  year = 2024,
+  year = 2025,
   url = "https://ropensci.github.io/git2rdata/",
   abstract = "The git2rdata package is an R package for writing and reading dataframes as plain text files. A metadata file stores important information. 1) Storing metadata allows to maintain the classes of variables. By default, git2rdata optimizes the data for file storage. The optimization is most effective on data containing factors. The optimization makes the data less human readable. The user can turn this off when they prefer a human readable format over smaller files. Details on the implementation are available in vignette(\"plain_text\", package = \"git2rdata\"). 2) Storing metadata also allows smaller row based diffs between two consecutive commits. This is a useful feature when storing data as plain text files under version control. Details on this part of the implementation are available in vignette(\"version_control\", package = \"git2rdata\"). Although we envisioned git2rdata with a git workflow in mind, you can use it in combination with other version control systems like subversion or mercurial. 3) git2rdata is a useful tool in a reproducible and traceable workflow. vignette(\"workflow\", package = \"git2rdata\") gives a toy example. 4) vignette(\"efficiency\", package = \"git2rdata\") provides some insight into the efficiency of file storage, git repository size and speed for writing and reading.",
-  textVersion = "Onkelinx, Thierry (2024) git2rdata: Store and Retrieve Data.frames in a Git Repository. Version 0.4.1. https://ropensci.github.io/git2rdata/",
+  textVersion = "Onkelinx, Thierry (2025) git2rdata: Store and Retrieve Data.frames in a Git Repository. Version 0.5.0. https://ropensci.github.io/git2rdata/",
   keywords = "git; version control; plain text data",
   doi = "10.5281/zenodo.1485309",
 )
diff --git a/man-roxygen/example_io.R b/man-roxygen/example_io.R
index a9adaed..6cf1922 100644
--- a/man-roxygen/example_io.R
+++ b/man-roxygen/example_io.R
@@ -6,7 +6,10 @@
 #' dir.create(root)
 #'
 #' # write a dataframe to the directory
-#' write_vc(iris[1:6, ], file = "iris", root = root, sorting = "Sepal.Length")
+#' write_vc(
+#'   iris[1:6, ], file = "iris", root = root, sorting = "Sepal.Length",
+#'   digits = 6
+#' )
 #' # check that a data file (.tsv) and a metadata file (.yml) exist.
 #' list.files(root, recursive = TRUE)
 #' # read the git2rdata object from the directory
diff --git a/man/data_package.Rd b/man/data_package.Rd
new file mode 100644
index 0000000..dff82cf
--- /dev/null
+++ b/man/data_package.Rd
@@ -0,0 +1,32 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/data_package.R
+\name{data_package}
+\alias{data_package}
+\title{Create a Data Package for a directory of CSV files}
+\usage{
+data_package(path = ".")
+}
+\arguments{
+\item{path}{the directory in which to create the \code{datapackage.json} file.}
+}
+\description{
+Create a \code{datapackage.json} file for a directory of CSV files.
+The function will look for all \code{.csv} files in the directory and its
+subdirectories.
+It will then create a \code{datapackage.json} file with the metadata of each CSV
+file.
+}
+\seealso{
+Other storage: 
+\code{\link{display_metadata}()},
+\code{\link{list_data}()},
+\code{\link{prune_meta}()},
+\code{\link{read_vc}()},
+\code{\link{relabel}()},
+\code{\link{rename_variable}()},
+\code{\link{rm_data}()},
+\code{\link{update_metadata}()},
+\code{\link{verify_vc}()},
+\code{\link{write_vc}()}
+}
+\concept{storage}
diff --git a/man/display_metadata.Rd b/man/display_metadata.Rd
index 732ba4f..11db43d 100644
--- a/man/display_metadata.Rd
+++ b/man/display_metadata.Rd
@@ -16,6 +16,7 @@ Display metadata for a \code{git2rdata} object
 }
 \seealso{
 Other storage: 
+\code{\link{data_package}()},
 \code{\link{list_data}()},
 \code{\link{prune_meta}()},
 \code{\link{read_vc}()},
diff --git a/man/list_data.Rd b/man/list_data.Rd
index 22dd8ed..b0b610e 100644
--- a/man/list_data.Rd
+++ b/man/list_data.Rd
@@ -92,6 +92,7 @@ status(repo)
 }
 \seealso{
 Other storage: 
+\code{\link{data_package}()},
 \code{\link{display_metadata}()},
 \code{\link{prune_meta}()},
 \code{\link{read_vc}()},
diff --git a/man/meta.Rd b/man/meta.Rd
index 58bf948..0d770f8 100644
--- a/man/meta.Rd
+++ b/man/meta.Rd
@@ -11,7 +11,7 @@
 \alias{meta.data.frame}
 \title{Optimize an Object for Storage as Plain Text and Add Metadata}
 \usage{
-meta(x, ...)
+meta(x, ..., digits)
 
 \method{meta}{character}(x, na = "NA", optimize = TRUE, ...)
 
@@ -30,7 +30,8 @@ meta(x, ...)
   sorting,
   strict = TRUE,
   split_by = character(0),
-  ...
+  ...,
+  digits
 )
 }
 \arguments{
@@ -38,6 +39,14 @@ meta(x, ...)
 
 \item{...}{further arguments to the methods.}
 
+\item{digits}{The number of significant digits of the smallest absolute
+value.
+The function applies the rounding automatically.
+Only relevant for numeric variables.
+Either a single positive integer or a named vector where the names link to
+the variables in the \code{data.frame}.
+Defaults to \code{6} with a warning.}
+
 \item{na}{the string to use for missing values in the data.}
 
 \item{optimize}{If \code{TRUE}, recode the data to get smaller text files.
@@ -93,7 +102,7 @@ Add \code{strict = FALSE} to enforce the new order of factor levels.
 \examples{
 meta(c(NA, "'NA'", '"NA"', "abc\tdef", "abc\ndef"))
 meta(1:3)
-meta(seq(1, 3, length = 4))
+meta(seq(1, 3, length = 4), digits = 6)
 meta(factor(c("b", NA, "NA"), levels = c("NA", "b", "c")))
 meta(factor(c("b", NA, "a"), levels = c("a", "b", "c")), optimize = FALSE)
 meta(factor(c("b", NA, "a"), levels = c("a", "b", "c"), ordered = TRUE))
diff --git a/man/prune_meta.Rd b/man/prune_meta.Rd
index 754f961..db5b73a 100644
--- a/man/prune_meta.Rd
+++ b/man/prune_meta.Rd
@@ -106,6 +106,7 @@ status(repo)
 }
 \seealso{
 Other storage: 
+\code{\link{data_package}()},
 \code{\link{display_metadata}()},
 \code{\link{list_data}()},
 \code{\link{read_vc}()},
diff --git a/man/read_vc.Rd b/man/read_vc.Rd
index 909bf7c..37174c9 100644
--- a/man/read_vc.Rd
+++ b/man/read_vc.Rd
@@ -38,7 +38,10 @@ root <- tempfile("git2rdata-")
 dir.create(root)
 
 # write a dataframe to the directory
-write_vc(iris[1:6, ], file = "iris", root = root, sorting = "Sepal.Length")
+write_vc(
+  iris[1:6, ], file = "iris", root = root, sorting = "Sepal.Length",
+  digits = 6
+)
 # check that a data file (.tsv) and a metadata file (.yml) exist.
 list.files(root, recursive = TRUE)
 # read the git2rdata object from the directory
@@ -91,6 +94,7 @@ status(repo)
 }
 \seealso{
 Other storage: 
+\code{\link{data_package}()},
 \code{\link{display_metadata}()},
 \code{\link{list_data}()},
 \code{\link{prune_meta}()},
diff --git a/man/recent_commit.Rd b/man/recent_commit.Rd
index 79fc8c7..4e3a30a 100644
--- a/man/recent_commit.Rd
+++ b/man/recent_commit.Rd
@@ -42,15 +42,19 @@ git2r::config(repo, user.name = "Alice", user.email = "alice@example.org")
 
 # write and commit a first dataframe
 # store the output of write_vc() minimize screen output
-junk <- write_vc(iris[1:6, ], "iris", repo, sorting = "Sepal.Length",
-                 stage = TRUE)
+junk <- write_vc(
+  iris[1:6, ], "iris", repo, sorting = "Sepal.Length", stage = TRUE,
+  digits = 6
+)
 commit(repo, "important analysis", session = TRUE)
 list.files(repo_path)
 Sys.sleep(1.1) # required because git doesn't handle subsecond timings
 
 # write and commit a second dataframe
-junk <- write_vc(iris[7:12, ], "iris2", repo, sorting = "Sepal.Length",
-                 stage = TRUE)
+junk <- write_vc(
+  iris[7:12, ], "iris2", repo, sorting = "Sepal.Length", stage = TRUE,
+  digits = 6
+)
 commit(repo, "important analysis", session = TRUE)
 list.files(repo_path)
 Sys.sleep(1.1) # required because git doesn't handle subsecond timings
diff --git a/man/relabel.Rd b/man/relabel.Rd
index 9d6486f..10be43f 100644
--- a/man/relabel.Rd
+++ b/man/relabel.Rd
@@ -82,6 +82,7 @@ status(repo)
 }
 \seealso{
 Other storage: 
+\code{\link{data_package}()},
 \code{\link{display_metadata}()},
 \code{\link{list_data}()},
 \code{\link{prune_meta}()},
diff --git a/man/rename_variable.Rd b/man/rename_variable.Rd
index 3fd8f25..5876df0 100644
--- a/man/rename_variable.Rd
+++ b/man/rename_variable.Rd
@@ -80,6 +80,7 @@ status(repo)
 }
 \seealso{
 Other storage: 
+\code{\link{data_package}()},
 \code{\link{display_metadata}()},
 \code{\link{list_data}()},
 \code{\link{prune_meta}()},
diff --git a/man/rm_data.Rd b/man/rm_data.Rd
index 21b4d77..606c48f 100644
--- a/man/rm_data.Rd
+++ b/man/rm_data.Rd
@@ -122,6 +122,7 @@ status(repo)
 }
 \seealso{
 Other storage: 
+\code{\link{data_package}()},
 \code{\link{display_metadata}()},
 \code{\link{list_data}()},
 \code{\link{prune_meta}()},
diff --git a/man/update_metadata.Rd b/man/update_metadata.Rd
index 968e138..3914b9f 100644
--- a/man/update_metadata.Rd
+++ b/man/update_metadata.Rd
@@ -4,7 +4,15 @@
 \alias{update_metadata}
 \title{Update the description of a \code{git2rdata} object}
 \usage{
-update_metadata(file, root = ".", field_description, name, title, description)
+update_metadata(
+  file,
+  root = ".",
+  field_description,
+  name,
+  title,
+  description,
+  ...
+)
 }
 \arguments{
 \item{file}{the name of the git2rdata object. Git2rdata objects cannot
@@ -24,6 +32,8 @@ The names of the vector must match the variable names.}
 \item{title}{a character string with the new title of the object.}
 
 \item{description}{a character string with the new description of the object.}
+
+\item{...}{parameters used in some methods}
 }
 \description{
 Allows to update the description of the fields, the table name, the title,
@@ -34,6 +44,7 @@ field from the metadata.
 }
 \seealso{
 Other storage: 
+\code{\link{data_package}()},
 \code{\link{display_metadata}()},
 \code{\link{list_data}()},
 \code{\link{prune_meta}()},
diff --git a/man/upgrade_data.Rd b/man/upgrade_data.Rd
index b103ead..467068e 100644
--- a/man/upgrade_data.Rd
+++ b/man/upgrade_data.Rd
@@ -54,9 +54,14 @@ root <- tempfile("git2rdata-")
 dir.create(root)
 
 # write dataframes to the root
-write_vc(iris[1:6, ], file = "iris", root = root, sorting = "Sepal.Length")
-write_vc(iris[5:10, ], file = "subdir/iris", root = root,
-         sorting = "Sepal.Length")
+write_vc(
+  iris[1:6, ], file = "iris", root = root, sorting = "Sepal.Length",
+  digits = 6
+)
+write_vc(
+  iris[5:10, ], file = "subdir/iris", root = root, sorting = "Sepal.Length",
+  digits = 6
+)
 # upgrade a single git2rdata object
 upgrade_data(file = "iris", root = root)
 # use path = "." to upgrade all git2rdata objects under root
diff --git a/man/verify_vc.Rd b/man/verify_vc.Rd
index 0867f7d..5be8d0d 100644
--- a/man/verify_vc.Rd
+++ b/man/verify_vc.Rd
@@ -24,6 +24,7 @@ data.frame.
 }
 \seealso{
 Other storage: 
+\code{\link{data_package}()},
 \code{\link{display_metadata}()},
 \code{\link{list_data}()},
 \code{\link{prune_meta}()},
diff --git a/man/write_vc.Rd b/man/write_vc.Rd
index 8a4e7d9..49f75c1 100644
--- a/man/write_vc.Rd
+++ b/man/write_vc.Rd
@@ -27,7 +27,9 @@ write_vc(
   optimize = TRUE,
   na = "NA",
   ...,
-  split_by = character(0)
+  append = FALSE,
+  split_by = character(0),
+  digits
 )
 
 \method{write_vc}{git_repository}(
@@ -79,6 +81,18 @@ Defaults to \code{TRUE}.}
 This creates a separate file for every combination.
 We prepend these variables to the vector of \code{sorting} variables.}
 
+\item{append}{logical. Only relevant if \code{file} is a character
+    string.  If \code{TRUE}, the output is appended to the
+    file.  If \code{FALSE}, any existing file of the name is destroyed.}
+
+\item{digits}{The number of significant digits of the smallest absolute
+value.
+The function applies the rounding automatically.
+Only relevant for numeric variables.
+Either a single positive integer or a named vector where the names link to
+the variables in the \code{data.frame}.
+Defaults to \code{6} with a warning.}
+
 \item{stage}{Logical value indicating whether to stage the changes after
 writing the data. Defaults to \code{FALSE}.}
 
@@ -107,7 +121,10 @@ root <- tempfile("git2rdata-")
 dir.create(root)
 
 # write a dataframe to the directory
-write_vc(iris[1:6, ], file = "iris", root = root, sorting = "Sepal.Length")
+write_vc(
+  iris[1:6, ], file = "iris", root = root, sorting = "Sepal.Length",
+  digits = 6
+)
 # check that a data file (.tsv) and a metadata file (.yml) exist.
 list.files(root, recursive = TRUE)
 # read the git2rdata object from the directory
@@ -160,6 +177,7 @@ status(repo)
 }
 \seealso{
 Other storage: 
+\code{\link{data_package}()},
 \code{\link{display_metadata}()},
 \code{\link{list_data}()},
 \code{\link{prune_meta}()},
diff --git a/tests/testthat/setup_test_data.R b/tests/testthat/setup_test_data.R
index fd47a4e..cbe3794 100644
--- a/tests/testthat/setup_test_data.R
+++ b/tests/testthat/setup_test_data.R
@@ -33,10 +33,21 @@ git2rdata:::set_local_locale(old_locale)
 sorted_test_data$test_character <- enc2utf8(sorted_test_data$test_character)
 rownames(sorted_test_data) <- NULL
 
+sorted_test_data_6 <- sorted_test_data
+sorted_test_data_6$test_numeric <- signif(sorted_test_data_6$test_numeric, 6)
+
+sorted_test_data_4 <- sorted_test_data
+sorted_test_data_4$test_numeric <- signif(sorted_test_data_4$test_numeric, 4)
+
+
 test_subset <- head(test_data, ceiling(test_n / 2))
 
 sorted_test_subset <- test_subset[order(test_subset$test_Date), ]
 rownames(sorted_test_subset) <- NULL
+sorted_test_subset_6 <- sorted_test_subset
+sorted_test_subset_6$test_numeric <- signif(
+  sorted_test_subset_6$test_numeric, 6
+)
 
 test_na <- test_data
 for (i in seq_along(test_na)) {
@@ -46,5 +57,6 @@ old_locale <- git2rdata:::set_c_locale()
 sorted_test_na <- test_na[
   order(test_na$test_Date, test_na$test_integer, test_na$test_numeric),
 ]
+sorted_test_na$test_numeric <- signif(sorted_test_na$test_numeric, 6)
 git2rdata:::set_local_locale(old_locale)
 rownames(sorted_test_na) <- NULL
diff --git a/tests/testthat/test_a_basics.R b/tests/testthat/test_a_basics.R
index 7f17f04..490a254 100644
--- a/tests/testthat/test_a_basics.R
+++ b/tests/testthat/test_a_basics.R
@@ -21,10 +21,9 @@ test_that("write_vc() and read_vc() on a file system", {
     "file should not contain '..'"
   )
   expect_is(
-    suppressWarnings(
-      output <- write_vc(
-        x = test_data, file = "test.txt", root = root, sorting = "test_Date"
-      )
+    output <- write_vc(
+      x = test_data, file = "test.txt", root = root, sorting = "test_Date",
+      digits = 6
     ),
     "character"
   )
@@ -32,31 +31,28 @@ test_that("write_vc() and read_vc() on a file system", {
   expect_identical(unname(output), c("test.tsv", "test.yml"))
   expect_true(all(file.exists(git2rdata:::clean_data_path(root, "test"))))
   expect_equal(
-    stored <- read_vc(file = "test.xls", root = root),
-    sorted_test_data,
+    stored <- read_vc(file = "test.xls", root = root), sorted_test_data_6,
     check.attributes = FALSE
   )
   for (i in colnames(stored)) {
     expect_equal(
-      stored[[i]],
-      sorted_test_data[[i]],
-      label = paste0("stored$", i),
+      stored[[i]], sorted_test_data_6[[i]], label = paste0("stored$", i),
       expected.label = paste0("sorted_test_data$", i)
     )
   }
   expect_identical(
-    suppressWarnings(write_vc(x = test_data, file = "test.xls", root = root)),
-    output
+    write_vc(x = test_data, file = "test.xls", root = root), output
   )
   expect_error(
     write_vc(
-      data.frame(junk = 5), file = "test", root = root, sorting = "junk"
+      data.frame(junk = 5), file = "test", root = root, sorting = "junk",
+      digits = 6
     ),
     "The data was not overwritten because of the issues below."
   )
   expect_error(
-    suppressWarnings(
-      write_vc(x = test_data, file = "test", root = root, optimize = FALSE)
+    write_vc(
+      x = test_data, file = "test", root = root, optimize = FALSE, digits = 6
     ),
     "New data is verbose, whereas old data was optimized"
   )
@@ -81,7 +77,7 @@ test_that("write_vc() and read_vc() on a file system", {
   expect_is(
     output <- write_vc(
       x = test_data, file = file.path("a", "verbose"), root = root,
-      sorting = "test_Date", optimize = FALSE
+      sorting = "test_Date", optimize = FALSE, digits = 6
     ),
     "character"
   )
@@ -90,14 +86,11 @@ test_that("write_vc() and read_vc() on a file system", {
   )
   expect_equal(
     stored <- read_vc(file = file.path("a", "verbose"), root = root),
-    sorted_test_data,
-    check.attributes = FALSE
+    sorted_test_data_6, check.attributes = FALSE
   )
   for (i in colnames(stored)) {
     expect_equal(
-      stored[[i]],
-      sorted_test_data[[i]],
-      label = paste0("stored$", i),
+      stored[[i]], sorted_test_data_6[[i]], label = paste0("stored$", i),
       expected.label = paste0("sorted_test_data$", i)
     )
   }
@@ -108,31 +101,30 @@ test_that("write_vc() and read_vc() on a file system", {
 
   expect_is(
     output <- write_vc(
-      test_na, file = "na", root = root,
+      test_na, file = "na", root = root, digits = 6,
       sorting = c("test_Date", "test_integer", "test_numeric")
     ),
     "character"
   )
   expect_equal(
     stored <- read_vc(file = "na", root = root),
-    sorted_test_na,
-    check.attributes = FALSE
+    sorted_test_na, check.attributes = FALSE
   )
   for (i in colnames(stored)) {
     expect_equal(
-      stored[[i]],
-      sorted_test_na[[i]],
-      label = paste0("stored$", i),
+      stored[[i]], sorted_test_na[[i]], label = paste0("stored$", i),
       expected.label = paste0("sorted_test_na$", i)
     )
   }
 
   expect_error(
-    write_vc(test_data, file = "error", root = root, sorting = 1),
+    write_vc(test_data, file = "error", root = root, sorting = 1, digits = 6),
     "sorting is not a character vector"
   )
   expect_error(
-    write_vc(test_data, file = "error", root = root, sorting = "junk"),
+    write_vc(
+      test_data, file = "error", root = root, sorting = "junk", digits = 6
+    ),
     "All sorting variables must be available"
   )
   expect_false(any(file.exists(git2rdata:::clean_data_path(root, "sorting"))))
@@ -164,19 +156,17 @@ test_that("write_vc() and read_vc() on a file system", {
   test_changed <- test_data
   test_changed$junk <- test_changed$test_character
   expect_error(
-    suppressWarnings(write_vc(test_changed, file = "sorting", root = root)),
+    write_vc(test_changed, file = "sorting", root = root),
     "New data has a different number of variables"
   )
   test_changed$test_character <- NULL
   expect_error(
-    suppressWarnings(write_vc(test_changed, file = "sorting", root = root)),
-    "New variables: junk"
+    write_vc(test_changed, file = "sorting", root = root), "New variables: junk"
   )
   test_changed <- test_data
   test_changed$test_character <- factor(test_changed$test_character)
   expect_error(
-    suppressWarnings(write_vc(test_changed, file = "sorting", root = root
-    )),
+    write_vc(test_changed, file = "sorting", root = root),
     "Change in class: 'test_character' from character to factor"
   )
   expect_error(
@@ -194,8 +184,7 @@ test_that("write_vc() and read_vc() on a file system", {
     ordered = FALSE
   )
   expect_error(
-    suppressWarnings(write_vc(test_changed, file = "sorting", root = root
-    )),
+    write_vc(test_changed, file = "sorting", root = root),
     "'test_ordered' changes from ordinal to nominal"
   )
 
@@ -203,22 +192,21 @@ test_that("write_vc() and read_vc() on a file system", {
   test_no$test_ordered <- NULL
   expect_is(
     output <- write_vc(
-      x = test_no, file = "no_ordered", root = root, sorting = "test_Date"
+      x = test_no, file = "no_ordered", root = root, sorting = "test_Date",
+      digits = 6
     ),
     "character"
   )
   sorted_test_no <- sorted_test_data
   sorted_test_no$test_ordered <- NULL
+  sorted_test_no$test_numeric <- signif(sorted_test_no$test_numeric, 6)
   expect_equal(
-    stored <- read_vc(file = "no_ordered", root = root),
-    sorted_test_no,
+    stored <- read_vc(file = "no_ordered", root = root), sorted_test_no,
     check.attributes = FALSE
   )
   for (i in colnames(stored)) {
     expect_equal(
-      stored[[i]],
-      sorted_test_no[[i]],
-      label = paste0("stored$", i),
+      stored[[i]], sorted_test_no[[i]], label = paste0("stored$", i),
       expected.label = paste0("sorted_test_data$", i)
     )
   }
@@ -227,82 +215,65 @@ test_that("write_vc() and read_vc() on a file system", {
 test_that(
   "meta() works on complex", {
     z <- complex(real = runif(10), imaginary = runif(10))
+    expect_equal(mz <- meta(z), z, check.attributes = FALSE)
+    expect_true(assertthat::has_attr(mz, "meta"))
     expect_equal(
-      mz <- meta(z),
-      z,
-      check.attributes = FALSE
+      attr(mz, "meta"), list(class = "complex"), check.attributes = FALSE
     )
-    expect_true(assertthat::has_attr(mz, "meta"))
-    expect_equal(attr(mz, "meta"), list(class = "complex"),
-                 check.attributes = FALSE)
   }
 )
 
-
 test_that("user specified na strings work", {
   x <- data.frame(
-    a = c(NA, "NA", "b"),
-    b = factor(c("NA", NA, "d")),
-    z = c(1:2, NA),
-    y = c(pi, NA, Inf),
-    stringsAsFactors = FALSE
+    a = c(NA, "NA", "b"), b = factor(c("NA", NA, "d")), z = c(1:2, NA),
+    y = c(pi, NA, Inf), stringsAsFactors = FALSE
   )
   root <- tempfile("na_string")
   dir.create(root)
   expect_error(
-    suppressWarnings(
-      write_vc(x, "test_na_string_verbose", root, "a", optimize = FALSE)
+    write_vc(
+      x, "test_na_string_verbose", root, "a", optimize = FALSE, digits = 6
     ),
     "one of the strings matches the NA string"
   )
   expect_is(
-    fn <- suppressWarnings(
-      write_vc(x, "test_na_string_verbose", root, "a", optimize = FALSE,
-               na = "junk")
+    fn <- write_vc(
+      x, "test_na_string_verbose", root, "a", optimize = FALSE, na = "junk",
+      digits = 6
     ),
     "character"
   )
   old_locale <- git2rdata:::set_c_locale()
-  expect_equal(
-    read_vc(fn[1], root),
-    x[order(x$a), ],
-    check.attributes = FALSE
-  )
+  target <- x[order(x$a), ]
+  target$y <- signif(target$y, 6)
+  expect_equal(read_vc(fn[1], root), target, check.attributes = FALSE)
   git2rdata:::set_local_locale(old_locale)
   expect_identical(
-    grep("junk", readLines(file.path(root, fn[1]), encoding = "UTF-8")),
-    2:4
+    grep("junk", readLines(file.path(root, fn[1]), encoding = "UTF-8")), 2:4
   )
   expect_error(
-    suppressWarnings(
-      write_vc(x, "test_na_string_verbose", root, "a", optimize = FALSE,
-               na = "different")
+    write_vc(
+      x, "test_na_string_verbose", root, "a", optimize = FALSE, na = "different"
     ),
     "New data uses 'different' as NA string, whereas old data used 'junk'"
   )
   expect_is(
-    fn <- suppressWarnings(
-      write_vc(x, "test_na_string_optimize", root, "a", na = "junk")
+    fn <- write_vc(
+      x, "test_na_string_optimize", root, "a", na = "junk", digits = 6
     ),
     "character"
   )
   old_locale <- git2rdata:::set_c_locale()
-  expect_equal(
-    read_vc(fn[1], root),
-    x[order(x$a), ],
-    check.attributes = FALSE
-  )
+  expect_equal(read_vc(fn[1], root), target, check.attributes = FALSE)
   git2rdata:::set_local_locale(old_locale)
   expect_identical(
-    grep("junk", readLines(file.path(root, fn[1]), encoding = "UTF-8")),
-    2:4
+    grep("junk", readLines(file.path(root, fn[1]), encoding = "UTF-8")), 2:4
   )
 })
 
 test_that("write_vc() allows changes in factor levels", {
   x <- data.frame(
-    test_factor = factor(c("a", "b")),
-    stringsAsFactors = FALSE
+    test_factor = factor(c("a", "b")), stringsAsFactors = FALSE
   )
   root <- tempfile("factor_levels")
   dir.create(root)
@@ -321,14 +292,78 @@ test_that("write_vc() allows changes in factor levels", {
   )
   x$test_factor <- factor(x$test_factor, levels = c("a", "b", "c"))
   expect_error(
-    write_vc(x, "factor_levels", root),
-    "New factor labels for 'test_factor'"
+    write_vc(x, "factor_levels", root), "New factor labels for 'test_factor'"
   )
 })
 
 test_that("meta attributes are printed as yaml", {
-  expect_output(print(suppressWarnings(attr(meta(test_data), "meta"))),
-                "hash: d8b9851bcc840c6203c39f70c514803e7acb96d0")
-  expect_output(print(attr(meta(test_data$test_factor), "meta")),
-                "class: factor.*\nordered: no")
+  expect_output(
+    print(suppressWarnings(attr(meta(test_data, digits = 6), "meta"))),
+    "hash: [0-9a-f]{40}"
+  )
+  expect_output(
+    print(attr(meta(test_data$test_factor), "meta")),
+    "class: factor.*\nordered: no"
+  )
+})
+
+test_that("digits works as expected", {
+  x <- data.frame(
+    a = c(exp(1), pi), b = c(1.23456789, 1.23456789),
+    stringsAsFactors = FALSE
+  )
+  root <- tempfile("digits")
+  dir.create(root)
+  expect_warning(
+    fn <- write_vc(x, "default", root, sorting = "a"),
+    "`digits` was not set."
+  )
+  expect_equal(
+    read_vc(fn[1], root), check.attributes = FALSE,
+    signif(x, 6)
+  )
+
+  expect_is(
+    fn <- write_vc(x, "digits", root, digits = 4, sorting = "a"),
+    "character"
+  )
+  expect_equal(
+    read_vc(fn[1], root), check.attributes = FALSE,
+    signif(x, 4)
+  )
+  write_vc(x, "digits", root, digits = 6)
+  expect_equal(
+    read_vc(fn[1], root), check.attributes = FALSE,
+    signif(x, 6)
+  )
+
+  expect_is(
+    fn <- write_vc(x, "delta", root, digits = c(a = 4, b = 5), sorting = "a"),
+    "character"
+  )
+  expect_equal(
+    read_vc(fn[1], root), check.attributes = FALSE,
+    data.frame(a = signif(x$a, 4), b = signif(x$b, 5))
+  )
+  expect_is(
+    fn <- write_vc(x, "delta", root, digits = c(a = 5, b = 4)),
+    "character"
+  )
+  expect_equal(
+    read_vc(fn[1], root), check.attributes = FALSE,
+    data.frame(a = signif(x$a, 5), b = signif(x$b, 4))
+  )
+
+  expect_error(
+    write_vc(x, "faults", root, digits = c(4, 5), sorting = "a"),
+    "`digits` must be either named"
+  )
+  expect_error(
+    write_vc(x, "faults", root, digits = c(a = 4, b = NA), sorting = "a"),
+    "`digits` must be a strict positive integer"
+  )
+  expect_error(
+    write_vc(x, "faults", root, digits = c(a = 4, c = 5), sorting = "a"),
+    "`digits` must contain all numeric variables"
+  )
 })
diff --git a/tests/testthat/test_a_coalesce.R b/tests/testthat/test_a_coalesce.R
new file mode 100644
index 0000000..f84022e
--- /dev/null
+++ b/tests/testthat/test_a_coalesce.R
@@ -0,0 +1,6 @@
+test_that("coalesce()", {
+  expect_equal(coalesce(), NULL)
+  expect_equal(coalesce(NULL), NULL)
+  expect_equal(coalesce(NULL, 1), 1)
+  expect_equal(coalesce(NULL, NULL, 1), 1)
+})
diff --git a/tests/testthat/test_b_is_git2rmeta.R b/tests/testthat/test_b_is_git2rmeta.R
index 3aa32f4..72ab715 100644
--- a/tests/testthat/test_b_is_git2rmeta.R
+++ b/tests/testthat/test_b_is_git2rmeta.R
@@ -29,7 +29,9 @@ test_that("is_git2rmeta checks metadata", {
   )
 
   file <- basename(tempfile(tmpdir = root))
-  junk <- write_vc(test_data, file = file, root = root, sorting = "test_Date")
+  junk <- write_vc(
+    test_data, file = file, root = root, sorting = "test_Date", digits = 6
+  )
   correct_yaml <- yaml::read_yaml(file.path(root, junk[2]))
 
   file.remove(file.path(root, junk[2]))
@@ -127,7 +129,9 @@ test_that("is_git2rmeta checks metadata", {
 
 test_that("is_git2rdata checks data", {
   file <- basename(tempfile(tmpdir = root))
-  junk <- write_vc(test_data, file = file, root = root, sorting = "test_Date")
+  junk <- write_vc(
+    test_data, file = file, root = root, sorting = "test_Date", digits = 6
+  )
   correct_yaml <- yaml::read_yaml(file.path(root, junk[2]))
   yaml::write_yaml(correct_yaml, file.path(root, junk[2]))
   correct_data <- readLines(file.path(root, junk[1]), encoding = "UTF-8")
@@ -163,7 +167,9 @@ git2r::config(root, user.name = "Alice", user.email = "alice@example.org")
 
 test_that("is_git2rmeta handle git repositories", {
   file <- basename(tempfile(tmpdir = git2r::workdir(root)))
-  junk <- write_vc(test_data, file = file, root = root, sorting = "test_Date")
+  junk <- write_vc(
+    test_data, file = file, root = root, sorting = "test_Date", digits = 6
+  )
   expect_true(is_git2rmeta(file = file, root = root))
   expect_true(is_git2rdata(file = file, root = root))
 })
diff --git a/tests/testthat/test_b_prune.R b/tests/testthat/test_b_prune.R
index 4fd70fc..22dbdc7 100644
--- a/tests/testthat/test_b_prune.R
+++ b/tests/testthat/test_b_prune.R
@@ -13,10 +13,13 @@ test_that("rm_data & prune_meta", {
   expect_error(prune_meta(root), root)
   dir.create(root)
   expect_null(prune_meta(root, path = "junk"))
-  write_vc(test_data, file = "test", root = root, sorting = "test_Date")
+  write_vc(
+    test_data, file = "test", root = root, sorting = "test_Date",
+    digits = 6
+  )
   write_vc(
     test_data, file = file.path("a", "verbose"), root = root,
-    sorting = "test_Date", optimize = FALSE
+    sorting = "test_Date", optimize = FALSE, digits = 6
   )
 
   current <- list.files(root, recursive = TRUE)
@@ -42,13 +45,15 @@ test_that("rm_data & prune_meta", {
   expect_identical(rm_data(root, path = "."), character(0))
   expect_identical(list.files(root, recursive = TRUE), current)
 
-  write_vc(test_data, file = "test1", root = root, sorting = "test_Date")
+  write_vc(
+    test_data, file = "test1", root = root, sorting = "test_Date", digits = 6
+  )
   junk <- write_vc(
-    test_data, file = "test2", root = root, sorting = "test_Date"
+    test_data, file = "test2", root = root, sorting = "test_Date", digits = 6
   )
   write_vc(
     test_data, file = file.path("a", "test2"), root = root,
-    sorting = "test_Date"
+    sorting = "test_Date", digits = 6
   )
   meta_data <- yaml::read_yaml(file.path(root, junk[2]))
   meta_data[["..generic"]] <- NULL
diff --git a/tests/testthat/test_b_update.R b/tests/testthat/test_b_update.R
index dfa72b9..8c5f2c8 100644
--- a/tests/testthat/test_b_update.R
+++ b/tests/testthat/test_b_update.R
@@ -18,7 +18,7 @@ original <- data.frame(
   stringsAsFactors = FALSE
 )
 test_that("updates to logical", {
-  write_vc(original, "logical", root, sorting = "test_logical")
+  write_vc(original, "logical", root, sorting = "test_logical", digits = 6)
   updated <- matrix(TRUE, ncol = ncol(original), dimnames = dimnames(original))
   updated <- as.data.frame(updated)
   expect_is(
@@ -30,7 +30,7 @@ test_that("updates to logical", {
   expect_equal(read_vc(fn[1], root), updated, check.attributes = FALSE)
 })
 test_that("updates to integer", {
-  write_vc(original, "integer", root, sorting = "test_logical")
+  write_vc(original, "integer", root, sorting = "test_logical", digits = 6)
   updated <- matrix(1L, ncol = ncol(original), dimnames = dimnames(original))
   updated <- as.data.frame(updated)
   expect_is(
@@ -42,7 +42,7 @@ test_that("updates to integer", {
   expect_equal(read_vc(fn[1], root), updated, check.attributes = FALSE)
 })
 test_that("updates to numeric", {
-  write_vc(original, "numeric", root, sorting = "test_logical")
+  write_vc(original, "numeric", root, sorting = "test_logical", digits = 6)
   updated <- matrix(pi, ncol = ncol(original), dimnames = dimnames(original))
   updated <- as.data.frame(updated)
   expect_is(
@@ -51,10 +51,12 @@ test_that("updates to numeric", {
     ),
     "character"
   )
-  expect_equal(read_vc(fn[1], root), updated, check.attributes = FALSE)
+  expect_equal(
+    read_vc(fn[1], root), signif(updated, 6), check.attributes = FALSE
+  )
 })
 test_that("updates to character", {
-  write_vc(original, "character", root, sorting = "test_logical")
+  write_vc(original, "character", root, sorting = "test_logical", digits = 6)
   updated <- matrix("xyz", ncol = ncol(original), dimnames = dimnames(original))
   updated <- as.data.frame(updated, stringsAsFactor = FALSE)
   expect_is(
@@ -66,7 +68,7 @@ test_that("updates to character", {
   expect_equal(read_vc(fn[1], root), updated, check.attributes = FALSE)
 })
 test_that("updates to factor", {
-  write_vc(original, "factor", root, sorting = "test_logical")
+  write_vc(original, "factor", root, sorting = "test_logical", digits = 6)
   updated <- matrix("xyz", ncol = ncol(original), dimnames = dimnames(original))
   updated <- apply(updated, 2, list)
   updated <- as.data.frame(lapply(updated, factor, levels = c("xyz", "abc")))
@@ -87,7 +89,7 @@ test_that("updates to factor", {
   )
 })
 test_that("updates to Date", {
-  write_vc(original, "Date", root, sorting = "test_logical")
+  write_vc(original, "Date", root, sorting = "test_logical", digits = 6)
   updated <- matrix(Sys.Date(), ncol = ncol(original),
                     dimnames = dimnames(original))
   updated <- as.data.frame(updated)
@@ -100,10 +102,13 @@ test_that("updates to Date", {
   expect_equal(read_vc(fn[1], root), updated, check.attributes = FALSE)
 })
 test_that("updates to POSIXct", {
-  write_vc(original, "POSIXct", root, sorting = "test_logical")
-  updated <- matrix(Sys.time(), ncol = ncol(original),
-                    dimnames = dimnames(original))
-  updated <- as.data.frame(updated)
+  write_vc(original, "POSIXct", root, sorting = "test_logical", digits = 6)
+  Sys.time() |>
+    as.POSIXct(tz = "UTC") |>
+    list() |>
+    rep(ncol(original)) |>
+    setNames(colnames(original)) |>
+    as.data.frame() -> updated
   expect_is(
     suppressWarnings(
       fn <- write_vc(updated, "POSIXct", root, strict = FALSE)
@@ -113,7 +118,7 @@ test_that("updates to POSIXct", {
   expect_equal(read_vc(fn[1], root), updated, check.attributes = FALSE)
 })
 test_that("updates to complex", {
-  write_vc(original, "complex", root, sorting = "test_logical")
+  write_vc(original, "complex", root, sorting = "test_logical", digits = 6)
   updated <- matrix(complex(imaginary = 1), ncol = ncol(original),
                     dimnames = dimnames(original))
   updated <- as.data.frame(updated)
diff --git a/tests/testthat/test_b_verify_vc.R b/tests/testthat/test_b_verify_vc.R
index 41f35f6..93210d7 100644
--- a/tests/testthat/test_b_verify_vc.R
+++ b/tests/testthat/test_b_verify_vc.R
@@ -2,7 +2,8 @@ test_that("verify_vc", {
   root <- tempfile(pattern = "git2rdata-verify-vc")
   dir.create(root)
   write_vc(
-    x = test_data, file = "test.txt", root = root, sorting = "test_integer"
+    x = test_data, file = "test.txt", root = root, sorting = "test_integer",
+    digits = 6
   )
   expect_s3_class(
     verify_vc("test.txt", root = root, variables = "test_integer"),
diff --git a/tests/testthat/test_c_git.R b/tests/testthat/test_c_git.R
index c4dd751..2d80371 100644
--- a/tests/testthat/test_c_git.R
+++ b/tests/testthat/test_c_git.R
@@ -8,7 +8,7 @@ git2r::add(root, ".gitignore")
 commit(root, "initial commit")
 expect_identical(rm_data(root, "."), character(0))
 untracked <- write_vc(
-  test_data, file = "untracked", root = root, sorting = "test_Date"
+  test_data, file = "untracked", root = root, sorting = "test_Date", digits = 6
 )
 expect_equal(
   status(root, ignored = TRUE),
@@ -19,21 +19,19 @@ expect_equal(
   check.attributes = FALSE
 )
 expect_equal(
-  stored <- read_vc(file = "untracked", root = root),
-  sorted_test_data,
+  stored <- read_vc(file = "untracked", root = root), sorted_test_data_6,
   check.attributes = FALSE
 )
 for (i in colnames(stored)) {
   expect_equal(
-    stored[[i]],
-    sorted_test_data[[i]],
-    label = paste0("stored$", i),
+    stored[[i]], sorted_test_data_6[[i]], label = paste0("stored$", i),
     expected.label = paste0("sorted_test_data$", i)
   )
 }
 
 staged <- write_vc(
-  test_data, file = "staged", root = root, sorting = "test_Date", stage = TRUE
+  test_data, file = "staged", root = root, sorting = "test_Date", stage = TRUE,
+  digits = 6
 )
 expect_equal(
   status(root, ignored = TRUE),
@@ -44,21 +42,19 @@ expect_equal(
   check.attributes = FALSE
 )
 expect_equal(
-  stored <- read_vc(file = "staged", root = root),
-  sorted_test_data,
+  stored <- read_vc(file = "staged", root = root), sorted_test_data_6,
   check.attributes = FALSE
 )
 for (i in colnames(stored)) {
   expect_equal(
-    stored[[i]],
-    sorted_test_data[[i]],
-    label = paste0("stored$", i),
+    stored[[i]], sorted_test_data_6[[i]], label = paste0("stored$", i),
     expected.label = paste0("sorted_test_data$", i)
   )
 }
 
 ignored <- write_vc(
-  test_data, file = "ignore", root = root, sorting = "test_Date", stage = TRUE
+  test_data, file = "ignore", root = root, sorting = "test_Date", stage = TRUE,
+  digits = 6
 )
 expect_equal(
   status(root, ignored = TRUE),
@@ -69,21 +65,18 @@ expect_equal(
   check.attributes = FALSE
 )
 expect_equal(
-  stored <- read_vc(file = "ignore", root = root),
-  sorted_test_data,
+  stored <- read_vc(file = "ignore", root = root), sorted_test_data_6,
   check.attributes = FALSE
 )
 for (i in colnames(stored)) {
   expect_equal(
-    stored[[i]],
-    sorted_test_data[[i]],
-    label = paste0("stored$", i),
+    stored[[i]], sorted_test_data_6[[i]], label = paste0("stored$", i),
     expected.label = paste0("sorted_test_data$", i)
   )
 }
 
 forced <- write_vc(
-  test_data, file = file.path("forced", "force"), root = root,
+  test_data, file = file.path("forced", "force"), root = root, digits = 6,
   sorting = "test_Date", stage = TRUE, force = TRUE
 )
 expect_equal(
@@ -98,22 +91,18 @@ expect_equal(
 )
 expect_equal(
   stored <- read_vc(file = file.path("forced", "force"), root = root),
-  sorted_test_data,
-  check.attributes = FALSE
+  sorted_test_data_6, check.attributes = FALSE
 )
 for (i in colnames(stored)) {
   expect_equal(
-    stored[[i]],
-    sorted_test_data[[i]],
-    label = paste0("stored$", i),
+    stored[[i]], sorted_test_data_6[[i]], label = paste0("stored$", i),
     expected.label = paste0("sorted_test_data$", i)
   )
 }
 commit(root, "add data")
 
 staged <- write_vc(
-  test_subset,
-  file = "staged", root = root, stage = FALSE
+  test_subset, file = "staged", root = root, stage = FALSE, digits = 6
 )
 expect_equal(
   status(root, ignored = TRUE),
@@ -124,22 +113,18 @@ expect_equal(
   check.attributes = FALSE
 )
 expect_equal(
-  stored <- read_vc(file = "staged", root = root),
-  sorted_test_subset,
+  stored <- read_vc(file = "staged", root = root), sorted_test_subset_6,
   check.attributes = FALSE
 )
 for (i in colnames(stored)) {
   expect_equal(
-    stored[[i]],
-    sorted_test_subset[[i]],
-    label = paste0("stored$", i),
+    stored[[i]], sorted_test_subset_6[[i]], label = paste0("stored$", i),
     expected.label = paste0("sorted_test_subset$", i)
   )
 }
 
 staged <- write_vc(
-  test_subset,
-  file = "staged", root = root, stage = TRUE
+  test_subset, file = "staged", root = root, stage = TRUE, digits = 6
 )
 expect_equal(
   status(root, ignored = TRUE),
@@ -150,15 +135,12 @@ expect_equal(
   check.attributes = FALSE
 )
 expect_equal(
-  stored <- read_vc(file = "staged", root = root),
-  sorted_test_subset,
+  stored <- read_vc(file = "staged", root = root), sorted_test_subset_6,
   check.attributes = FALSE
 )
 for (i in colnames(stored)) {
   expect_equal(
-    stored[[i]],
-    sorted_test_subset[[i]],
-    label = paste0("stored$", i),
+    stored[[i]], sorted_test_subset_6[[i]], label = paste0("stored$", i),
     expected.label = paste0("sorted_test_subset$", i)
   )
 }
@@ -167,13 +149,11 @@ commit(root, "update data")
 expect_null(prune_meta(root, path = "junk"))
 
 staged <- write_vc(
-  test_data,
-  file = "staged", root = root, stage = TRUE
+  test_data, file = "staged", root = root, stage = TRUE, digits = 6
 )
 current <- list.files(git2r::workdir(root), recursive = TRUE)
 expect_identical(
-  rm_data(root = root, path = "."),
-  file.path("forced", "force.tsv")
+  rm_data(root = root, path = "."), file.path("forced", "force.tsv")
 )
 expect_identical(
   current[!current %in% list.files(git2r::workdir(root), recursive = TRUE)],
@@ -200,8 +180,7 @@ expect_null(prune_meta(root, path = "."))
 git2r::reset(git2r::last_commit(root), reset_type = "hard", path = ".")
 
 staged <- write_vc(
-  test_data,
-  file = "staged", root = root, stage = TRUE
+  test_data, file = "staged", root = root, stage = TRUE
 )
 expect_identical(
   rm_data(root = root, path = ".", type = "m"),
@@ -225,8 +204,7 @@ expect_identical(
 git2r::reset(git2r::last_commit(root), reset_type = "hard", path = ".")
 
 staged <- write_vc(
-  test_data,
-  file = "staged", root = root, stage = TRUE
+  test_data, file = "staged", root = root, stage = TRUE
 )
 expect_identical(
   rm_data(root = root, path = ".", type = "i", stage = TRUE),
@@ -250,12 +228,10 @@ expect_identical(
 git2r::reset(git2r::last_commit(root), reset_type = "hard", path = ".")
 
 ignored <- write_vc(
-  test_data, file = "ignore", root = root, sorting = "test_Date", stage = TRUE
-)
-staged <- write_vc(
-  test_data,
-  file = "staged", root = root, stage = TRUE
+  test_data, file = "ignore", root = root, sorting = "test_Date", stage = TRUE,
+  digits = 6
 )
+staged <- write_vc(test_data, file = "staged", root = root, stage = TRUE)
 expect_identical(
   rm_data(root = root, path = ".", type = "all", stage = TRUE),
   c(
diff --git a/tests/testthat/test_d_description.R b/tests/testthat/test_d_description.R
index d6a3140..9eed121 100644
--- a/tests/testthat/test_d_description.R
+++ b/tests/testthat/test_d_description.R
@@ -11,18 +11,20 @@ test_that("description", {
 
   expect_is(
     write_vc(
-      x = test_data, file = "test.txt", root = root, sorting = "test_Date"
+      x = test_data, file = "test.txt", root = root, sorting = "test_Date",
+      digits = 6
     ),
     "character"
   )
 
-  expect_null(
+  expect_type(
     update_metadata(
       file = "test", root = root, field_description = c(
         test_character = "Some information", test_factor = "Some information",
         test_integer = "Some information"
       )
-    )
+    ),
+    "character"
   )
 
   expect_is({
@@ -48,12 +50,13 @@ test_that("description", {
   git2r::add(root, ".gitignore")
   commit(root, "initial commit")
 
-  expect_null(
+  expect_type(
     update_metadata(
       file = "test", root = root, name = "my_table", title = "My Table",
       description = "This is description for the unit tests",
       field_description = c(test_character = NA, test_factor = "")
-    )
+    ),
+    "character"
   )
   expect_is({
       output <- read_vc("test", root = root)
@@ -68,4 +71,29 @@ test_that("description", {
   expect_output(print(output), "display_metadata")
   expect_output(summary(output), "display_metadata")
   expect_output(display_metadata(output), "Table name: my_table")
+
+  expect_is(current_status <- status(root), "git_status")
+  expect_equal(
+    unname(unlist(current_status$untracked)), c("test.tsv", "test.yml")
+  )
+  expect_equal(unname(current_status$staged), list())
+
+  expect_type(
+    update_metadata(
+      file = "test", root = root, name = "staged_table", title = "Staged table",
+      description = "This is description for the unit tests", stage = TRUE,
+      field_description = c(test_character = NA, test_factor = "")
+    ),
+    "character"
+  )
+  expect_is({
+    output <- read_vc("test", root = root)
+  }, "git2rdata"
+  )
+  expect_output(display_metadata(output), "Table name: staged_table")
+
+  expect_is(current_status <- status(root), "git_status")
+  expect_equal(unname(unlist(current_status$untracked)), "test.tsv")
+  expect_equal(unname(unlist(current_status$staged)), "test.yml")
+
 })
diff --git a/tests/testthat/test_d_recent_commit.R b/tests/testthat/test_d_recent_commit.R
index 38e9237..699c962 100644
--- a/tests/testthat/test_d_recent_commit.R
+++ b/tests/testthat/test_d_recent_commit.R
@@ -15,13 +15,13 @@ git2r::config(root, user.name = "Alice", user.email = "alice@example.org")
 
 write_vc(
   test_data[1:2, ], file = "test1", root = root, stage = TRUE,
-  sorting = "test_Date"
+  sorting = "test_Date", digits = 6
 )
 commit_1 <- commit(root, "initial commit")
 
 write_vc(
   test_data[3:4, ], file = file.path("junk", "test1"), root = root,
-  stage = TRUE, sorting = "test_Date"
+  stage = TRUE, sorting = "test_Date", digits = 6
 )
 commit_2 <- commit(root, "second file")
 
@@ -34,7 +34,7 @@ commit_3 <- commit(root, "update first file")
 
 write_vc(
   test_data[7:8, ], file = "test3", root = root, stage = TRUE,
-  sorting = "test_Date"
+  sorting = "test_Date", digits = 6
 )
 Sys.sleep(subsecond)
 commit_4 <- commit(root, "add third file")
diff --git a/tests/testthat/test_e_data_package.R b/tests/testthat/test_e_data_package.R
new file mode 100644
index 0000000..2578abb
--- /dev/null
+++ b/tests/testthat/test_e_data_package.R
@@ -0,0 +1,28 @@
+test_that("datapackage", {
+  root <- tempfile("datapackage")
+  dir.create(root)
+  write_vc(
+    x = test_data, file = "human_readable", root = root, optimize = FALSE,
+    sorting = "test_integer", digits = 4
+  )
+  expect_identical(
+    data_package(path = root), file.path(root, "datapackage.json")
+  )
+  write_vc(
+    x = test_data, file = "human_readable_meta", root = root, optimize = FALSE,
+    sorting = "test_integer", digits = 4
+  )
+  update_metadata(
+    file = "human_readable_meta", root = root, title = "Test title",
+    description = "Test description", name = "test",
+    field_description = c(
+      test_integer = "Test integer", test_numeric = "Test numeric",
+      test_character = "Test character", test_factor = "Test factor",
+      test_logical = "Test logical", test_Date = "Test date",
+      test_POSIXct = "Test POSIXct", test_ordered = "Test ordered"
+    )
+  )
+  expect_identical(
+    data_package(path = root), file.path(root, "datapackage.json")
+  )
+})
diff --git a/tests/testthat/test_e_validate_metadata.R b/tests/testthat/test_e_validate_metadata.R
index 4a0e38c..7501f1a 100644
--- a/tests/testthat/test_e_validate_metadata.R
+++ b/tests/testthat/test_e_validate_metadata.R
@@ -3,7 +3,9 @@ root <- tempfile("git2rdata-check-meta")
 dir.create(root)
 test_that("read_vc() checks hash", {
   file <- basename(tempfile(tmpdir = root))
-  junk <- write_vc(test_data, file = file, root = root, sorting = "test_Date")
+  junk <- write_vc(
+    test_data, file = file, root = root, sorting = "test_Date", digits = 6
+  )
   correct_yaml <- yaml::read_yaml(file.path(root, junk[2]))
   junk_yaml <- correct_yaml
   junk_yaml[["test_Date"]] <- NULL
@@ -34,7 +36,9 @@ test_that("read_vc() checks hash", {
 
 test_that("read_vc() handles changes in rawdata", {
   file <- basename(tempfile(tmpdir = root))
-  junk <- write_vc(test_data, file = file, root = root, sorting = "test_Date")
+  junk <- write_vc(
+    test_data, file = file, root = root, sorting = "test_Date", digits = 6
+  )
   correct_data <- readLines(file.path(root, junk[1]), encoding = "UTF-8")
   correct_header <- strsplit(correct_data[1], "\t")[[1]]
   junk_data <- correct_data
@@ -51,7 +55,9 @@ test_that("read_vc() handles changes in rawdata", {
 
 test_that("write_vc() checks existing metadata", {
   file <- basename(tempfile(tmpdir = root))
-  junk <- write_vc(test_data, file = file, root = root, sorting = "test_Date")
+  junk <- write_vc(
+    test_data, file = file, root = root, sorting = "test_Date", digits = 6
+  )
   correct_yaml <- yaml::read_yaml(file.path(root, junk[2]))
   junk_yaml <- correct_yaml
   junk_yaml[["test_Date"]] <- NULL
diff --git a/tests/testthat/test_f_split_by.R b/tests/testthat/test_f_split_by.R
index 921bce5..418b888 100644
--- a/tests/testthat/test_f_split_by.R
+++ b/tests/testthat/test_f_split_by.R
@@ -15,13 +15,13 @@ test_that("write_vc() handles the split_by argument", {
   )
   expect_equal(
     z[order(z$test_numeric), ],
-    test_data[order(test_data$test_numeric), ],
+    sorted_test_data_6[order(sorted_test_data_6$test_numeric), ],
     check.attributes = FALSE
   )
 
   expect_is({
     sorted_file <- write_vc(
-      test_data, file = "sorted", root = root,
+      test_data, file = "sorted", root = root, digits = 6,
       sorting = "test_Date", split_by = "test_factor"
     )
   },
@@ -35,13 +35,16 @@ test_that("write_vc() handles the split_by argument", {
   )
   expect_equal(
     z,
-    test_data[order(test_data$test_factor, test_data$test_Date), ],
+    sorted_test_data_6[
+      order(sorted_test_data_6$test_factor, sorted_test_data_6$test_Date),
+    ],
     check.attributes = FALSE
   )
 
   expect_error(
     write_vc(
-      test_data, file = "sorted", root = root, split_by = character(0)
+      test_data, file = "sorted", root = root, split_by = character(0),
+      digits = 6
     ),
     "The split_by variables changed."
   )
diff --git a/tests/testthat/test_g_rename_variable.R b/tests/testthat/test_g_rename_variable.R
index 78dc202..a22dc5a 100644
--- a/tests/testthat/test_g_rename_variable.R
+++ b/tests/testthat/test_g_rename_variable.R
@@ -29,7 +29,8 @@ test_that("rename_variable() handles single files", {
   git2r::reset(cm, "hard")
 
   files <- write_vc(
-    test_data, file = "sorted", root = repo, sorting = "test_Date", stage = TRUE
+    test_data, file = "sorted", root = repo, sorting = "test_Date",
+    stage = TRUE, digits = 6
   )
   cm <- commit(repo, "sorted")
   # staged & sorted on changed variable
@@ -73,7 +74,7 @@ test_that("rename_variable() handles single files", {
   expect_identical(length(updated), length(change))
   expect_identical(colnames(test_data)[updated], unname(change))
   expect_identical(colnames(changed_df)[updated], names(change))
-  expect_equivalent(sorted_test_data[, change], changed_df[, names(change)])
+  expect_equivalent(sorted_test_data_6[, change], changed_df[, names(change)])
   git2r::reset(cm, "hard")
 })
 
@@ -111,7 +112,7 @@ test_that("rename_variable() handles split_by files", {
 
   files <- write_vc(
     test_data, file = "sorted", root = repo, sorting = "test_Date",
-    split_by = "test_factor", stage = TRUE
+    split_by = "test_factor", stage = TRUE, digits = 6
   )
   cm <- commit(repo, "sorted")
   # staged & sorted on changed variable
@@ -184,7 +185,9 @@ test_that("rename_variable() handles split_by files", {
   expect_identical(colnames(test_data)[updated], unname(change))
   expect_identical(colnames(changed_df)[updated], names(change))
   expect_equivalent(
-    test_data[order(test_data$test_factor, test_data$test_Date), change],
+    signif(
+      test_data[order(test_data$test_factor, test_data$test_Date), change], 6
+    ),
     changed_df[, names(change)]
   )
   git2r::reset(cm, "hard")