After is a contingency that occurs after the first n attempts.

Always is a contingency that always occurs.

First is a contingency that occurs during the first n attempts.

Never is a contingency that never occurs.

None is a convenience function for specifying a no-fault.

Random is a contingency that occurs with a probability equal to the given p-value.

Spec outlines the conditions for a fault, comprising a contingency, as well as an error that is reported when said contingency arises.

Fault is an injector of simulated errors.

Contingency is a condition under which a fault should be injected.