expect_output_file overhaul

* Set width to 80. Fixes #514
* Save output on first run. Fixes #554
* Supply print argument. Fixes #517

NEWS.md

@@ -1,5 +1,11 @@
 # testthat 1.0.2.9000
 
+* `expect_output_file()` now:
+
+  * Sets the width to 80 to ensure consistent output (#514)
+  * Saves the output on the first run (#554)
+  * Correctly calls internal `expect_output_file()` to avoid error (#517)
+
 * `expect_error()` gains a `class` argument that allows you to make an assertion
   about the class of the error object (#530).
 

R/evaluate-promise.R

@@ -100,15 +100,19 @@ get_messages <- function(x) {
 
 #' @export
 #' @rdname evaluate_promise
-capture_output <- function(code, print = FALSE) {
-  output <- capture_output_as_vector(code, print)
+#' @param width Number of characters per line of output
+capture_output <- function(code, print = FALSE, width = 80) {
+  output <- capture_output_as_vector(code, print, width = width)
   paste0(output, collapse = "\n")
 }
 
-capture_output_as_vector <- function(code, print) {
+capture_output_as_vector <- function(code, print, width = 80) {
   temp <- file()
   on.exit(close(temp), add = TRUE)
 
+  old <- options(width = width)
+  on.exit(options(old), add = TRUE)
+
   result <- with_sink(temp, withVisible(code))
   if (result$visible && print) {
     with_sink(temp, print(result$value))

R/expect-output.R

@@ -111,15 +111,24 @@ expect_output <- function(object, regexp = NULL, ..., info = NULL, label = NULL)
 #' @export
 #' @rdname output-expectations
 #' @param file Path to a "golden" text file that contains the desired output.
-#' @param update Should the "golden" text file be updated? Default: \code{FALSE}.
+#' @param update Should the "golden" text file be updated? Defaults to
+#'   \code{FALSE}, but that it will automatically create output if the file
+#'   does not exist (i.e. on the first run).
+#' @inheritParams capture_output
 expect_output_file <- function(object, file, update = FALSE, ...,
-                               info = NULL, label = NULL) {
+                               info = NULL, label = NULL, width = 80) {
   lab <- make_label(object, label)
-  output <- capture_output_as_vector(object)
 
+  output <- capture_output_as_vector(object, print = FALSE, width = width)
+  if (!file.exists(file)) {
+    writeLines(output, file)
+  }
+
+  expr <- bquote(
+    expect_equal(output, safe_read_lines(.(file)), ..., info = info, label = lab)
+  )
   withCallingHandlers(
-    eval(bquote(
-      expect_equal(output, safe_read_lines(.(file)), ..., info = info, label = lab))),
+    eval(expr),
     expectation = function(e) {
       if (update && expectation_failure(e)) {
         tryCatch(writeLines(output, file), error = function(e) NULL)

tests/testthat/test-expect-output.R

@@ -27,6 +27,23 @@ test_that("... passed on to grepl", {
   expect_success(expect_output(print("X"), "x", ignore.case = TRUE))
 })
 
+
+# expect_output_file ------------------------------------------------------
+
+test_that("expect_output_file uses specified width", {
+  old <- options(width = 20)
+  on.exit(options(old), add = TRUE)
+
+  x <- 1:100
+  expect_output_file(print(x), "width-80.txt")
+})
+
+test_that("expect_output_file creates file on first run", {
+  file <- tempfile()
+  expect_success(expect_output_file(cat("ok!\n"), file))
+  expect_true(file.exists(file))
+})
+
 test_that("expect_output_file works, also with incomplete last line", {
   file <- tempfile()
   writeLines("Hi!", file)
@@ -44,11 +61,3 @@ test_that("expect_output_file can update file but does not by default", {
   expect_failure(expect_output_file(cat("oops"), file, update = TRUE))
   expect_success(expect_output_file(cat("oops"), file))
 })
-
-test_that("expect_output_file warns if file missing, but can update it", {
-  file <- tempfile()
-  expect_warning(expect_failure(expect_output_file(cat("oops"), file)))
-  expect_false(file.exists(file))
-  expect_warning(expect_failure(expect_output_file(cat("oops"), file, update = TRUE)))
-  expect_success(expect_output_file(cat("oops"), file))
-})

tests/testthat/width-80.txt

@@ -0,0 +1,6 @@
+  [1]   1   2   3   4   5   6   7   8   9  10  11  12  13  14  15  16  17  18
+ [19]  19  20  21  22  23  24  25  26  27  28  29  30  31  32  33  34  35  36
+ [37]  37  38  39  40  41  42  43  44  45  46  47  48  49  50  51  52  53  54
+ [55]  55  56  57  58  59  60  61  62  63  64  65  66  67  68  69  70  71  72
+ [73]  73  74  75  76  77  78  79  80  81  82  83  84  85  86  87  88  89  90
+ [91]  91  92  93  94  95  96  97  98  99 100