S3 dispatch check

Author: MichaelChirico

tests/testthat/test-expect-shape.R

@@ -3,6 +3,7 @@ test_that("length compared correctly", {
   expect_snapshot_failure(expect_shape(1, length = 2))
   expect_success(expect_shape(1:10, length = 10))
   expect_success(expect_shape(letters[1:5], length = 5))
+  expect_success(expect_shape(integer(), length = 0))
 })
 
 test_that("dim compared correctly", {
@@ -38,6 +39,13 @@ test_that("ncol compared correctly", {
   expect_success(expect_shape(array(dim = dd), ncol = 0L))
 })
 
+test_that("uses S3 dim method", {
+  dim.testthat_expect_shape <- function(x) 1:2
+  x <- integer()
+  class(x) <- "testthat_expect_shape"
+  expect_success(expect_shape(x, dim = 1:2))
+})
+
 test_that("uses S4 dim method", {
   A <- setClass("ExpectShapeA", slots = c(x = "numeric", y = "numeric"))
   setMethod("dim", "ExpectShapeA", function(x) 8:10)