Does code return NULL?

This is a special case because NULL is a singleton so it's possible check for it either with expect_equal(x, NULL) or expect_type(x, "NULL").

expect_null(object, info = NULL, label = 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.
info	Extra information to be included in the message. This argument is soft-deprecated and should not be used in new code. Instead see alternatives in quasi_label.
label	Used to customise failure messages. For expert use only.

See also

Other expectations: comparison-expectations, equality-expectations, expect_error(), expect_length(), expect_match(), expect_named(), expect_output(), expect_reference(), expect_silent(), inheritance-expectations, logical-expectations

Examples

x <- NULL
y <- 10

expect_null(x)
show_failure(expect_null(y))
#> Failed expectation:
#> `y` is not NULL
#> 
#> `actual` is a double vector (10)
#> `expected` is NULL