Support numeric args

r-lib · Aug 31, 2023 · 6a20d6c · 6a20d6c
1 parent 2ce9c49
commit 6a20d6c
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Showing 3 changed files with 60 additions and 3 deletions.
diff --git a/R/standalone-types-check.R b/R/standalone-types-check.R
@@ -425,18 +425,35 @@ check_function <- function(x,
   }
 
   actual_args <- fn_fmls_names(f) %||% character()
+  n_actual_args <- length(actual_args)
+
+  if (is.numeric(expected_args)) {
+    n_expected_args <- expected_args
+    if (identical(n_expected_args, n_actual_args)) {
+      return(invisible(NULL))
+    }
+
+    message <- sprintf(
+      "%s must have %i %s, not %i %s.",
+      format_arg(arg),
+      n_expected_args,
+      pluralise(n_actual_args, "argument", "arguments"),
+      n_actual_args,
+      pluralise(n_actual_args, "argument", "arguments")
+    )
+    abort(message, call = call, arg = arg)
+  }
+
   if (identical(actual_args, expected_args)) {
     return(invisible(NULL))
   }
 
   n_expected_args <- length(expected_args)
-  n_actual_args <- length(actual_args)
-
   if (n_expected_args == 0) {
     message <- sprintf(
       "%s must have no arguments, not %i %s.",
       format_arg(arg),
-      length(actual_args),
+      n_actual_args,
       pluralise(n_actual_args, "argument", "arguments")
     )
     abort(message, call = call, arg = arg)

diff --git a/tests/testthat/_snaps/standalone-types-check.md b/tests/testthat/_snaps/standalone-types-check.md
@@ -424,6 +424,33 @@
       Error in `checker()`:
       ! `foo` must be a function, not a symbol.
 
+---
+
+    Code
+      err(checker(function(x) x, args = 0L, check_function))
+    Output
+      <error/rlang_error>
+      Error in `checker()`:
+      ! `foo` must have 0 argument, not 1 argument.
+    Code
+      err(checker(function(x, y) x, args = 0L, check_function))
+    Output
+      <error/rlang_error>
+      Error in `checker()`:
+      ! `foo` must have 0 arguments, not 2 arguments.
+    Code
+      err(checker(function() x, args = 2, check_function))
+    Output
+      <error/rlang_error>
+      Error in `checker()`:
+      ! `foo` must have 2 arguments, not 0 arguments.
+    Code
+      err(checker(function(x, y, z) x, args = 2, check_function))
+    Output
+      <error/rlang_error>
+      Error in `checker()`:
+      ! `foo` must have 2 arguments, not 3 arguments.
+
 ---
 
     Code

diff --git a/tests/testthat/test-standalone-types-check.R b/tests/testthat/test-standalone-types-check.R
@@ -150,6 +150,19 @@ test_that("`check_function()` checks", {
     err(checker(quote(foo), check_function))
   })
 
+  expect_null(check_function(function() x, args = 0L))
+  expect_null(check_function(function(x, y) x, args = 2L))
+
+  expect_snapshot({
+    # should have no arguments
+    err(checker(function(x) x, args = 0L, check_function))
+    err(checker(function(x, y) x, args = 0L, check_function))
+
+    # should have arguments
+    err(checker(function() x, args = 2, check_function))
+    err(checker(function(x, y, z) x, args = 2, check_function))
+  })
+
   expect_null(check_function(function() x, args = character()))
   expect_null(check_function(function(x) x, args = "x"))
   expect_null(check_function(function(x, y) x, args = c("x", "y")))