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Validation - Function

test_function.Rd

Test if an object is a function, with options to inspect function type, argument names, environments, S3 generics, and methods.

Usage

test_function(
  x,
  mode = "function",
  args_names = NULL,
  fn_env = NULL,
  dots = NULL,
  sentinels = NULL,
  custom = NULL
)

assert_function(
  x,
  mode = "function",
  args_names = NULL,
  fn_env = NULL,
  dots = NULL,
  sentinels = NULL,
  custom = NULL,
  action = "abort",
  env = caller_env(),
  x_name = NULL,
  short_circuit = TRUE,
  report_untested = TRUE,
  args_cnd = list()
)

Arguments

x

[any] An object to test.

mode

["function" | "closure" | "builtin" | "special" | "primitive" | NULL] Expected function type(s) out of "function" (any function), "closure", "builtin", "special", or "primitive" (any of the former two). Set to NULL to not test.

args_names

[character() | NULL] Expected exact argument names of the function. Set to NULL to not test.

fn_env

[environment | NULL] Expected environment of the function. Checks if fn_env(x) is identical to env or inherits from it via rlang::env_inherits(). Set to NULL to not test.

dots

[TRUE | FALSE | NULL] Test if the function has ... in its arguments. Set to NULL to not test.

sentinels

[character() | NULL] Each entry in this character vector allows x to also be some scalar sentinel below. Set to NULL to disconsider sentinels.

  • "null" for NULL.

  • "empty" for any zero-length object.

  • "na" for any NA type, or "na_logical" for NA, "na_integer" for NA_integer_, "na_real" for NA_real_, "na_complex" for NA_complex_, and "na_character" for NA_character_.

  • "nan" for NaN.

  • "+inf" for +Inf, "-inf" for -Inf, and "inf" for both.

  • "true"/"t" for TRUE, and "false"/"f" for FALSE.

custom

[function(x) | NULL] A custom function that takes x as first argument and returns a single TRUE or FALSE. Set to NULL to not test.

action

["abort" | "warn" | "inform"] Action to take when the test fails:

  • "abort" to stop execution and throw an error.

  • "warning" to issue a warning and return invisible(x).

  • "message" to issue a message and return invisible(x).

env

[environment() | call() | NULL | missing_arg()] The call to inform as the origin of the error, passed to rlang::abort():

  • An environment in the call stack or a hard-coded defused call.

  • NULL for no information.

  • missing_arg() to use the assert function itself.

  • The default is caller_env(), to display the function where the assertion was called.

x_name

[character(1) | NULL] The name of the object to use in the error message. If NULL, the name is inferred from the expression passed to x.

short_circuit

[TRUE | FALSE] If TRUE, the tests results will be reported up to the first failure. Else, all tests results are reported. The former is more efficient, while the latter is more informative.

report_untested

[TRUE | FALSE] If TRUE, the tests that were not run due to short- circuiting will be reported as untested, else, ignored.

args_cnd

[list()] Additional arguments passed to cli::cli_abort(), cli::cli_warn(), or cli::cli_inform(), based on the chosen action.

Value

  • [TRUE | FALSE] for test_function().

  • [=x] invisible(x) for assert_function(), or aborts if the test fails.

Examples

x <- function(a, b = 1, ...) {
  a + b
}

args <- list(
  mode = "closure",            # Must be a standard closure function (will pass)
  args_names = c("a", "b"),    # Exact argument names must match (will fail)
  fn_env = rlang::global_env(),
  # Function environment must equal or inherit from global env (will pass)
  dots = TRUE,                 # Function must accept `...` in arguments (will pass)
  sentinels = c("null"),       # Allow NULL function (not the case of x)
  custom = NULL                # No custom predicate
)

do.call(test_function, c(list(x), args)) #> FALSE (not all tests passed)
#> [1] FALSE

try(do.call(assert_function, c(list(x), args, short_circuit = FALSE))) #> Error
#> Error in eval(expr, envir) : `x` failed `assert_function()`:
#> ✔ (pass) sentinels: no sentinel values allowed.
#> ✔ (pass) type  : must be of type "closure".
#> ✖ (fail) args_names: must have argument names "a" and "b". Had "a", "b", and
#>   "...".
#> ✔ (pass) fn_env: must have the expected environment.
#> ✔ (pass) dots  : must accept `...`.
#> 
#> ℹ See `predicater::assert_function()` and this condition's `rs_assert_error`
#>   attribute for details.