Check looks for an input to f, any function that returns bool, such that f returns false.

CheckEqual looks for an input on which f and g return different results.

Value returns an arbitrary value of the given type.

A CheckEqualError is the result CheckEqual finding an error.

A CheckError is the result of Check finding an error.

A Config structure contains options for running a test.

A Generator can generate random values of its own type.

A SetupError is the result of an error in the way that check is being used, independent of the functions being tested.