Clojurians Log v2

Personally I recommend writing two generation functions, one that takes a generation depth and generates a full data structure to that depth, and another that takes a generation depth and generates a "narrow" structure to the given depth. This way you can test with the first one to a low depth to see "wide" structure generation, and use a much higher generation depth for the narrow one, using a weighted rng to choose which one to generate when using a with-gen form in the spec.

@adam678

Or as you've noted, recursive-gen already provides a reasonable solution, in that case you can also use that with spec's facilities to wrap something with a custom generator.

(require '[clojure.test.check.generators :as gen])

(s/def ::bool
  boolean?)

(def data-gen (gen/recursive-gen gen/vector gen/boolean))

(s/def ::vec
  (s/with-gen
    (s/coll-of ::data)
    (gen/vector data-gen)))

(s/def ::data
  (s/with-gen
    (s/or :bool ::bool
          :vec ::vec)
    data-gen))

For reference, the clojure spec generators are just a reexport of the functions in clojure.test.check.generators, which means that you can use them interchangeably.

well, almost interachangeably - most of the spec apis actually take a no-arg function that returns a generator instead of a generator (to allow for dynamic require/invoke)

Oh that's good to know. Thanks for the heads up on that.