schema: support generation of oneof and (empty) bytes

src/clojobuf/schema.cljc

@@ -2,6 +2,7 @@
   (:require [clojobuf.constant :refer [sint32-max sint32-min sint53-max sint53-min sint64-max sint64-min uint32-max uint32-min uint64-max uint64-min]]
             [clojobuf.util :refer [dot-qualify]]
             [clojure.set :refer [map-invert]]
+            [clojure.test.check.generators :as gen]
             [malli.core :as m]))
 
 (defn- qualify-name [package name]
@@ -75,7 +76,7 @@
    {:type `OneOf
     :compile (fn [_properties [oneof targets] _options]
                (when-not (and (keyword? oneof)
-                              (every? keyword? targets)) 
+                              (every? keyword? targets))
                  (m/-fail! ::invalid-children {:oneof oneof :targets targets}))
                {:pred (fn [kvs] (if-let [target (kvs oneof)]
                                   (and (contains? kvs target)
@@ -84,7 +85,20 @@
                 :min 2 ;; at least 1 child
                 :max 2 ;; at most 1 child
                 :type-properties  {:error/fn (fn [_error _reg] {oneof (str "oneof condition not met: only this field's target can be set but not the other targets" )})
-                                   :error/path [oneof]}})}))
+                                   :error/path [oneof]
+                                   :gen/gen (gen/return (let [target (rand-nth targets)] {oneof target, target nil}))}})}))
+
+(def Bytes
+  (m/-simple-schema
+   {:type `Bytes
+    :compile (fn [_properties [] _options]
+               {:pred #?(:clj bytes?
+                         :cljs #(= js/Uint8Array (type %)))
+                :min 0 ;; no child
+                :max 0 ;; no child 
+                :type-properties {:error/message "must be byte array"
+                                  :gen/gen (gen/return #?(:clj (byte-array 0)
+                                                          :cljs (js/Uint8Array.)))}})}))
 
 ; -------------------- msg validator -----------------------------
 (def vschemas-pb-types {:int32     [:int {:min sint32-min, :max sint32-max}]
@@ -103,8 +117,7 @@
                                                                                   (>= v 0)
                                                                                   (<= v uint64-max)))]]
                                       :cljs [:int {:min uint64-min, :max uint64-max}])
-                        :bytes     #?(:clj 'bytes?
-                                      :cljs [:fn (fn [v] (= js/Uint8Array (type v)))])
+                        :bytes     Bytes
                         :oneof     OneOf})
 
 (defn- get-malli-type [typ]