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% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/expect-that.R
\name{fail}
\alias{fail}
\alias{pass}
\title{Declare that an expectation either passes or fails}
\usage{
fail(
message = "Failure has been forced",
info = NULL,
srcref = NULL,
trace_env = caller_env(),
trace = NULL
)
pass()
}
\arguments{
\item{message}{A character vector describing the failure. The
first element should describe the expected value, and the second (and
optionally subsequence) elements should describe what was actually seen.}
\item{info}{Character vector continuing additional information. Included
for backward compatibility only and new expectations should not use it.}
\item{srcref}{Location of the failure. Should only needed to be explicitly
supplied when you need to forward a srcref captured elsewhere.}
\item{trace_env}{If \code{trace} is not specified, this is used to generate an
informative traceback for failures. You should only need to set this if
you're calling \code{fail()} from a helper function; see
\code{vignette("custom-expectation")} for details.}
\item{trace}{An optional backtrace created by \code{\link[rlang:trace_back]{rlang::trace_back()}}.
When supplied, the expectation is displayed with the backtrace.
Expert use only.}
}
\description{
These are the primitives that you can use to implement your own expectations.
Every path through an expectation should either call \code{pass()}, \code{fail()},
or throw an error (e.g. if the arguments are invalid). Expectations should
always return \code{invisible(act$val)}.
Learn more about creating your own expectations in
\code{vignette("custom-expectation")}.
}
\examples{
expect_length <- function(object, n) {
act <- quasi_label(rlang::enquo(object), arg = "object")
act_n <- length(act$val)
if (act_n != n) {
fail(sprintf("\%s has length \%i, not length \%i.", act$lab, act_n, n))
} else {
pass()
}
invisible(act$val)
}
}
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