testthat (version 0.8.1)

shows_message: Expectation: does expression show a message?

Description

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

Usage

shows_message(regexp = NULL, all = FALSE, ...)
expect_message(object, regexp = NULL, ..., info = NULL, label = NULL)

Arguments

regexp

optional regular expression to match. If not specified, just asserts that expression shows some message.

all

if TRUE, all messages must match given regular expression; if FALSE (the default), then only only message 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, 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, is_false; expect_identical, is_identical_to; expect_is, is_a; expect_match, matches; expect_named, has_names; expect_null, is_null; expect_output, prints_text; expect_true, is_true; expect_warning, gives_warning; takes_less_than

Examples

f <- function(x) {
  if (x < 0) message("*x* is already negative")
  -x
}
expect_that(f(-1), shows_message())
expect_that(f(-1), shows_message("already negative"))
expect_that(f(1), shows_message())

expect_message(f(-1))
expect_message(f(-1), "already negative")
expect_message(f(1))

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