Type-level marker to indicate whether a GenCurrencySymbol can have an ADA CurrencySymbol inside it or not.

Since: 2.1.3

A helper (opaque) newtype for QuickCheck use with CurrencySymbols. Has a type-level tag to indicate whether or not it could potentially contain a CurrencySymbol. We provide instances of Arbitrary, CoArbitrary and Function around this newtype, intended to act on the CurrencySymbol inside it.

The easiest way to use this newtype is by pattern matching:

forAll arbitrary $ \(GenCurrencySymbol @WithAdaSymbol sym) -> ...

You can also 're-wrap' for shrinking:

shrink $ GenCurrencySymbol @WithAdaSymbol sym

However, as GenCurrencySymbol instances do not shrink, there's not much point.

Since: 2.1.3

A helper (opaque) newtype for QuickCheck use with Values. Has two type arguments, to indicate, in order, what kind of amounts ADA and non-ADA entries are allowed to have.

The Values wrapped inside this type are phase-1 valid; the only validity we can't guarantee is to do with amounts, as these depend on choice of modifiers.

The easiest way to use this newtype is by pattern matching:

forAll arbitrary $ \(GenValue @NonNegative @Positive val) -> ...

In this case, the ADA entry in val would contain a non-negative amount, but any other entry would contain a strictly positive one.

You can also 're-wrap' for shrinking:

shrink $ GenValue @NonNegative @Positive val

Note

As GenValue relies heavily on Coercible to work, the newtype constructors of your modifiers need to be in scope, or you will get strange errors. For example, if you want to do

GenValue @NonNegative @Positive val <- arbitrary

you must have both the NonNegative and Positive types, as well as their newtype constructors, imported.

Since: 2.1.3

Represents a change in POSIXTime. The mod argument gives the kind of change, represented by a QuickCheck modifier, while the n argument is a closed (inclusive) upper bound on the magnitude of the change.

For example, TimeDelta Positive 100 represents a change in POSIXTime from 1 to 100 units, while TimeDelta NonPositive 250 represents a change in POSIXTime from 0 to -250. Modifiers intended to work with this type are:

• Positive
• Negative
• NonPositive
• NonNegative
• NonZero

The instances for TimeDelta reflect this decision: while other modifiers could potentially be useful, this ensures that we have safe behaviour and efficient instances.

NonZero is treated a bit specially in that the magnitude indicated by n is in both the negative and positive direction. Thus, TimeDelta NonZero 50 spans the union of [-50, -1] and [1, 50].

Shrinking a TimeDelta will shrink towards zero: more specifically, it will reduce the magnitude of the change.

To control what TimeDelta you get, the easiest method is a type signature:

forAll arbitrary $ \(delta :: TimeDelta NonNegative 100) -> ...

Since: 2.1.4

A CPS-style Property handler for applying a TimeDelta to a POSIXTime. If the application of the delta to the time would produce an impossible result (that is, the resulting time is negative), this will automatically fail the property test with an informative message; otherwise, it will apply the delta, and produce a new POSIXTime, which it will pass to the function argument to determine the outcome.

The arguments are ordered to conveniently use with forAll and similar.

Since: 2.1.4

A generic CPS-style handler for the application of a TimeDelta. The handler function argument will be passed Nothing if applying the TimeDelta would produce an impossible (that is, negative) POSIXTime, and a Just with the new POSIXTime otherwise.

Since: 2.1.4