Add read_only flag to run_test

R/testing.R

@@ -43,7 +43,8 @@ run_test <- function(hook_name,
                      artifacts = NULL,
                      file_transformer = function(files) files,
                      env = character(),
-                     expect_success = is.null(std_err)) {
+                     expect_success = is.null(std_err),
+                     read_only = FALSE) {
   withr::local_envvar(list(R_PRECOMMIT_HOOK_ENV = "1"))
   path_executable <- fs::dir_ls(system.file(
     fs::path("hooks", "exported"),
@@ -62,7 +63,8 @@ run_test <- function(hook_name,
     artifacts = ensure_named(artifacts),
     file_transformer = file_transformer,
     env = env,
-    expect_success = expect_success
+    expect_success = expect_success,
+    read_only = read_only
   )
 }
 
@@ -84,6 +86,8 @@ run_test <- function(hook_name,
 #' @param expect_success Whether or not an exit code 0 is expected. This can
 #'   be derived from `std_err`, but sometimes, non-empty stderr does not mean
 #'   error, but just a message.
+#' @param read_only If `TRUE` and `artifacts` are not `NULL`, then assert that hook
+#'   did not modify the artifacts.
 #' @keywords internal
 run_test_impl <- function(path_executable,
                           path_candidate,
@@ -93,7 +97,8 @@ run_test_impl <- function(path_executable,
                           artifacts,
                           file_transformer,
                           env,
-                          expect_success) {
+                          expect_success,
+                          read_only) {
   # ensure cannonical /private/var/... not /var/... on macOS
   tempdir <- fs::path(normalizePath((fs::dir_create(fs::file_temp()))))
   copy_artifacts(artifacts, tempdir)
@@ -128,6 +133,13 @@ run_test_impl <- function(path_executable,
     std_out,
     exit_status
   )
+  if (isTRUE(read_only) && !is.null(artifacts)) {
+    purrr::iwalk(artifacts, function(reference_path, temp_path) {
+      artifact_before_hook <- readLines(testthat::test_path(reference_path))
+      artifact_after_hook <- readLines(fs::path_join(c(tempdir, temp_path)))
+      testthat::expect_equal(artifact_before_hook, artifact_after_hook)
+    })
+  }
 }
 
 

vignettes/hook-order.Rmd

@@ -21,21 +21,23 @@ Read only hooks should generally run only after write hooks.
 -   Only add a dependency once, i.e. if styler must run before roxygen, add the requirement to styler or roxygen, not both. This makes keeping track easier.
 -   The hooks must appear in an order that meets all constraints, not just randomly order constraints.
 
-## Hooks with dependencies:
+## Hooks with dependencies
 
-**Read and write**
+### Read and write
 
--   styler: should run before roxygen because of caching. Caches.
--   roxygen. Caches.
--   codemeta: must be before tidy description.
--   use-tidy-description.
+-   style-files - caches; should run before roxygenize because of the caching
+-   roxygenize - caches
+-   codemeta-description-updated - must be before use-tidy-description
+-   use-tidy-description
+-   spell-check - updates `inst/WORDLIST`; should run after roxygenize
 
-**Just read:**
+### Read only
 
--   spell check; run after roxygen
--   lintr: should run after styler.
--   readme-rmd-rendered: Must run after styler.
+-   lintr - should run after styler
+-   readme-rmd-rendered - must run after styler
 -   parsable-R
 -   no-browser-statement
 -   no-print-statement
--   deps in desc.
+-   no-debug-statement
+-   deps-in-desc
+-   pkgdown