Add expect_no_lint (#2582)

NAMESPACE

@@ -57,6 +57,7 @@ export(expect_length_linter)
 export(expect_lint)
 export(expect_lint_free)
 export(expect_named_linter)
+export(expect_no_lint)
 export(expect_not_linter)
 export(expect_null_linter)
 export(expect_s3_class_linter)

NEWS.md

@@ -54,7 +54,8 @@
 * `vector_logic_linter()` is extended to recognize incorrect usage of scalar operators `&&` and `||` inside subsetting expressions like `dplyr::filter(x, A && B)` (#2166, @MichaelChirico).
 * `any_is_na_linter()` is extended to catch the unusual usage `NA %in% x` (#2113, @MichaelChirico).
 * `make_linter_from_xpath()` errors up front when `lint_message` is missing (instead of delaying this error until the linter is used, #2541, @MichaelChirico).
-* `paste_linter()`  is extended to recommend using `paste()` instead of `paste0()` for simply aggregating a character vector with `collapse=`, i.e., when `sep=` is irrelevant (#1108, @MichaelChirico).
+* `paste_linter()` is extended to recommend using `paste()` instead of `paste0()` for simply aggregating a character vector with `collapse=`, i.e., when `sep=` is irrelevant (#1108, @MichaelChirico).
+* `expect_no_lint()` was added as new function to cover the typical use case of expecting no lint message, akin to the recent {testthat} functions like `expect_no_warning()` (#2580, @F-Noelle).
 
 ### New linters
 

R/expect_lint.R

@@ -1,6 +1,8 @@
 #' Lint expectation
 #'
-#' This is an expectation function to test that the lints produced by `lint` satisfy a number of checks.
+#' These are expectation functions to test specified linters on sample code in the `testthat` testing framework.
+#' * `expect_lint` asserts that specified lints are generated.
+#' * `expect_no_lint` asserts that no lints are generated.
 #'
 #' @param content a character vector for the file content to be linted, each vector element representing a line of
 #' text.
@@ -22,7 +24,7 @@
 #' @return `NULL`, invisibly.
 #' @examples
 #' # no expected lint
-#' expect_lint("a", NULL, trailing_blank_lines_linter())
+#' expect_no_lint("a", trailing_blank_lines_linter())
 #'
 #' # one expected lint
 #' expect_lint("a\n", "trailing blank", trailing_blank_lines_linter())
@@ -42,7 +44,8 @@
 expect_lint <- function(content, checks, ..., file = NULL, language = "en") {
   if (!requireNamespace("testthat", quietly = TRUE)) {
     stop( # nocov start
-      "'expect_lint' is designed to work within the 'testthat' testing framework, but 'testthat' is not installed.",
+      "'expect_lint' and 'expect_no_lint' are designed to work within the 'testthat' testing framework, ",
+      "but 'testthat' is not installed.",
       call. = FALSE
     ) # nocov end
   }
@@ -123,6 +126,11 @@ expect_lint <- function(content, checks, ..., file = NULL, language = "en") {
   invisible(NULL)
 }
 
+#' @rdname expect_lint
+#' @export
+expect_no_lint <- function(content, ..., file = NULL, language = "en") {
+  expect_lint(content, NULL, ..., file = file, language = language)
+}
 
 #' Test that the package is lint free
 #'

tests/testthat/test-expect_lint.R

@@ -6,9 +6,9 @@ linter <- assignment_linter()
 lint_msg <- "Use <-, not ="
 
 test_that("no checks", {
-  expect_success(expect_lint("a", NULL, linter))
-  expect_success(expect_lint("a=1", NULL, list()))
-  expect_failure(expect_lint("a=1", NULL, linter))
+  expect_success(expect_no_lint("a", linter))
+  expect_success(expect_no_lint("a=1", list()))
+  expect_failure(expect_no_lint("a=1", linter))
 })
 
 test_that("single check", {

vignettes/creating_linters.Rmd

@@ -217,7 +217,7 @@ The main three aspects to test are:
 1. Linter returns no lints when there is nothing to lint, e.g.
 
 ```r
-expect_lint("blah", NULL, assignment_linter())
+expect_no_lint("blah", assignment_linter())
 ```
 
 2. Linter returns a lint when there is something to lint, e.g.