Spec Integration

A big advantage of Clojure's official QuickCheck implementation test.check is its integration with Clojure spec. With spec you can specify the structure of your data in any detail you want. Spec allows you to generate sample data that conforms to such a specification and which you can use in your property-based tests. We currently try to make active-quickcheck work with Clojure spec.

You can enter the spec world with spec. You need to provide something that is a valid spec such as in the following example.

(ns a
  (:require [clojure.spec.alpha :as s])
  (use active.quickcheck))

(quickcheck (property [x (spec (s/and integer? even?))]
                      (some-predicate x)))

Supported spec forms

We are currently supporting a subset of spec constructs that you can work with:

Base generators: integer?, string?, keyword?

(property [x (spec integer?)]
          ...)

Defined specs

(s/def ::deffed string?)
(property [x (spec ::deffed)]
          ...)

map-of

(property [x (s/map-of integer? string?)]
          ...)

coll-of, along with all kwargs except :unique

(property [x (s/coll-of integer? :kind vector? :min-count 23 :max-count 25)
           y (s/coll-of string? :count 32)]
          ...)

and and or

(property [x (s/and integer? even? #(> % 100))
           y (s/or string? keyword?)]
          ...)

Sets as enums

(property [x #{:a :b :c}]
          ...)

To Do

• You can currently use spec only to generate data but not to generate functions that take a spec as domain or range.
• We need to support more base generators such as symbol? etc.
• A lot of the combinators such as map-of take kwargs that modify the specs in some regards. We already implemented some of these kwargs with coll-of. We should make this implementation work with the other combinators as well.