testthat (version 0.9.1)

gives_warning: Expectation: does expression give a warning?

Description

Needs to match at least one of the warnings produced by the expression.

Usage

gives_warning(regexp = NULL, all = FALSE, ...)
expect_warning(object, regexp = NULL, ..., info = NULL, label = NULL)

Arguments

regexp

optional regular expression to match. If not specified, just asserts that expression gives some warning.

all

if TRUE, all warnings must match given regular expression; if FALSE (the default), then only only warning needs to match

...

other arguments passed to matches

object

object to test

info

extra information to be included in the message (useful when writing tests in loops).

label

object label. When NULL, computed from deparsed object.

See Also

Other expectations: equals_reference, expect_equal_to_reference; equals, expect_equal; expect-compare, expect_less_than, expect_more_than, is_less_than, is_more_than; expect_equivalent, is_equivalent_to; expect_error, throws_error; expect_false, expect_true, is_false, is_true; expect_identical, is_identical_to; expect_is, is_a; expect_match, matches; expect_message, shows_message; expect_named, has_names; expect_null, is_null; expect_output, prints_text; takes_less_than

Examples

f <- function(x) {
  if (x < 0) warning("*x* is already negative")
  -x
}
expect_warning(f(-1))
expect_warning(f(-1), "already negative")
expect_warning(f(1))

# You can use the arguments of grepl to control the matching
expect_warning(f(-1), "*x*", fixed = TRUE)
expect_warning(f(-1), "NEGATIVE", ignore.case = TRUE)