In module Test§

See primary documentation in context for sub fails-like

sub fails-like ( \test where Callable:D|Str:D$ex-type$reason?*%matcher)

Same interface as throws-like, except checks that the code returns a Failure instead of throwing. If the code does throw or if the returned Failure has already been handled, that will be considered as a failed test.

fails-like { +"a" }X::Str::Numeric,
    :message(/'Cannot convert string to number'/),
    'converting non-numeric string to number fails';