berryFunctions (version 1.22.5)

is.error: Check if an expression returns an error

Description

Does a given expression return an error? Useful for tests where you want to make sure your function throws an error.

Usage

is.error(expr, tell = FALSE, force = FALSE)

Value

TRUE/FALSE

Arguments

expr

Expression to be tested for returning an error

tell

Logical: Should the error message be printed via message? DEFAULT: FALSE

force

Logical: Should an error be returned if the expression is not an error? DEFAULT: FALSE

Author

Berry Boessenkool, , May 2016

See Also

stop, try, inherits

Examples

is.error(  log(3)              )
is.error(  log("a")            )
is.error(  log(3),   tell=TRUE )
is.error(  log("a"), tell=TRUE )
stopifnot( is.error( log("a")  )  ) # or shorter:
is.error(  log("a"), force=TRUE)
# is.error(  log(3),   force=TRUE)
stopifnot(is.error(  is.error(log(3), force=TRUE)  ))