R Under development (unstable) (2024-05-22 r86590 ucrt) -- "Unsuffered Consequences"
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Platform: x86_64-w64-mingw32/x64

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> source("helper/helper.R")
> 
> wb = function(n, ...) backports:::...elt(n)
> 
> if (exists("...elt", envir = baseenv())) {
+   f = get("...elt", envir = baseenv())
+   wf = function(n, ...) f(n)
+   expect_same = makeCompareFun(wf, wb)
+ 
+   expect_same(1, 1, 2, 3)
+   expect_same(2, 1, 2, 3)
+   expect_same(3, 1, 2, 3)
+ }
> 
> expect_identical(wb(1, "a", "b", "c"), "a")
> expect_identical(wb(2, "a", "b", "c"), "b")
> expect_identical(wb(3, "a", "b", "c"), "c")
> expect_error(wb(0, "a"), "non-positive")
> expect_error(wb(2, "a"), "does not contain")
> 
> proc.time()
   user  system elapsed 
   0.25    0.09    0.31