Does code return a vector with the expected size and/or prototype?

expect_vector() is a thin wrapper around vctrs::vec_assert(), converting the results of that function in to the expectations used by testthat. This means that it used the vctrs of ptype (prototype) and size. See details in https://vctrs.r-lib.org/articles/type-size.html

expect_vector(object, ptype = NULL, size = NULL)

Arguments

object	Object to test. Supports limited unquoting to make it easier to generate readable failures within a function or for loop. See quasi_label for more details.
ptype	(Optional) Vector prototype to test against. Should be a size-0 (empty) generalised vector.
size	(Optional) Size to check for.

Examples

if (requireNamespace("vctrs") && packageVersion("vctrs") > "0.1.0.9002") {
expect_vector(1:10, ptype = integer(), size = 10)
show_failure(expect_vector(1:10, ptype = integer(), size = 5))
show_failure(expect_vector(1:10, ptype = character(), size = 5))
}
#> Failed expectation:
#> `1:10` must have size 5, not size 10.
#> Failed expectation:
#> `1:10` must be a vector with type <character>.
#> Instead, it has type <integer>.