Assert that a condition is true — assert

A general-purpose check for any condition that does not have its own dedicated assertion. condition must be a single TRUE; anything else (FALSE, NA, a non-logical, or a vector) fails. Provide message to describe the requirement in your own words.

Usage

assert_true(
  condition,
  message = NULL,
  arg = rlang::caller_arg(condition),
  call = rlang::caller_env()
)

Arguments

condition: A single logical value that must be TRUE.
message: Optional custom error message. If omitted, a generic message naming the condition expression is used.
arg: Name used to refer to condition in the default error message. Defaults to the condition expression.
call: Environment used as the error's call context. Defaults to the calling function, so errors point at the user's code.

Value

The input condition, invisibly.

Examples

x <- 5
assert_true(x > 0)
assert_true(x %% 2 == 1, message = "x must be odd.")