Add use_snapshot()

NAMESPACE

@@ -166,6 +166,7 @@ export(use_rmarkdown_template)
 export(use_roxygen_md)
 export(use_rstudio)
 export(use_rstudio_preferences)
+export(use_snapshot)
 export(use_spell_check)
 export(use_standalone)
 export(use_template)

NEWS.md

@@ -3,6 +3,7 @@
 * Removes deprecated `use_tidy_style()` from to-do's from upkeep (@edgararuiz)
 
 * `pr_resume()` (without a specific `branch`) and `pr_fetch()` (without a specific `number`) no longer error when a branch name contains curly braces (#2107, @jonthegeek).
+* `use_snapshot()` is a new function to open a testthat snapshot file corresponding to a given test/R file (#2156, @jonthegeek).
 
 # usethis 3.2.1
 

R/r.R

@@ -1,13 +1,14 @@
-#' Create or edit R or test files
+#' Create or edit R, test, and snapshot files
 #'
-#' This pair of functions makes it easy to create paired R and test files,
+#' @description
+#' This family of functions makes it easy to create paired R and test files,
 #' using the convention that the tests for `R/foofy.R` should live
-#' in `tests/testthat/test-foofy.R`. You can use them to create new files
-#' from scratch by supplying `name`, or if you use RStudio, you can call
-#' to create (or navigate to) the companion file based on the currently open
-#' file. This also works when a test snapshot file is active, i.e. if you're
-#' looking at `tests/testthat/_snaps/foofy.md`, `use_r()` or `use_test()` take
-#' you to `R/foofy.R` or `tests/testthat/test-foofy.R`, respectively.
+#' in `tests/testthat/test-foofy.R` and the results of any snapshot tests live
+#' in `tests/testthat/snaps/foofy.md`.
+#'
+#' You can use them to create new files from scratch by supplying `name`, or
+#' if you use RStudio or Positron, you can call to create (or navigate to) the
+#' companion file based on the currently open file.
 #'
 #' @section Renaming files in an existing package:
 #'
@@ -41,7 +42,7 @@
 #' The [rename_files()] function can also be helpful.
 #'
 #' @param name Either a string giving a file name (without directory) or
-#'   `NULL` to take the name from the currently open file in RStudio.
+#'   `NULL` to take the name from the currently open file in RStudio/Positron.
 #' @inheritParams edit_file
 #' @seealso
 #' * The [testing](https://r-pkgs.org/testing-basics.html) and
@@ -88,6 +89,27 @@ use_test <- function(name = NULL, open = rlang::is_interactive()) {
   invisible(TRUE)
 }
 
+#' @rdname use_r
+#' @export
+use_snapshot <- function(
+  name = NULL,
+  open = rlang::is_interactive()
+) {
+  if (!uses_testthat()) {
+    use_testthat_impl()
+  }
+
+  snap_name <- compute_name(name, ext = "md")
+  path <- proj_path("tests", "testthat", "_snaps", snap_name)
+
+  if (!file_exists(path)) {
+    cli::cli_abort("No snapshot file exists for {.var {snap_name}}.")
+  }
+  edit_file(path, open = open)
+
+  invisible(TRUE)
+}
+
 #' Create or edit a test helper file
 #'
 #' This function creates (or opens) a test helper file, typically
@@ -183,7 +205,11 @@ compute_active_name <- function(path, ext, error_call = caller_env()) {
   path <- proj_path_prep(path_expand_r(path))
 
   dir <- path_dir(proj_rel_path(path))
-  if (!dir %in% c("R", "src", "tests/testthat", "tests/testthat/_snaps")) {
+  if (
+    !dir %in% c("R", "src", "tests/testthat", "tests/testthat/_snaps") &&
+      # This makes sure variants are also supported.
+      !grepl("tests/testthat/_snaps", dir)
+  ) {
     cli::cli_abort(
       "Open file must be code, test, or snapshot.",
       call = error_call

_pkgdown.yml

@@ -57,6 +57,7 @@ reference:
   - use_import_from
   - use_r
   - use_rmarkdown_template
+  - use_snapshot
   - use_spell_check
   - use_test
   - use_test_helper

tests/testthat/_snaps/r.md

@@ -1,3 +1,11 @@
+# use_snapshot() errors for non-existent snapshot file
+
+    Code
+      use_snapshot("foo", open = FALSE)
+    Condition
+      Error in `use_snapshot()`:
+      ! No snapshot file exists for `foo.md`.
+
 # use_test_helper() creates a helper file
 
     Code

tests/testthat/test-r.R

@@ -10,6 +10,24 @@ test_that("use_test() creates a test file", {
   expect_proj_file("tests", "testthat", "test-foo.R")
 })
 
+test_that("use_snapshot() errors for non-existent snapshot file", {
+  create_local_package()
+  expect_snapshot(
+    error = TRUE,
+    use_snapshot("foo", open = FALSE)
+  )
+})
+
+test_that("use_snapshot() works for existing snapshot file", {
+  create_local_package()
+  path <- proj_path("tests", "testthat", "_snaps", "foo.md")
+  use_directory(path("tests", "testthat", "_snaps"))
+  write_utf8(path, "## Snapshot for foo")
+  expect_no_error(
+    use_snapshot("foo", open = FALSE)
+  )
+})
+
 test_that("use_test_helper() creates a helper file", {
   create_local_package()