Merge pull request #1141 from frenchy64/issue-1121-seqable-nil-gen

Close #1121: don't generate nil if :seqable is non-empty

Author: ikitommi

src/malli/generator.cljc

@@ -145,9 +145,13 @@
     (gen/one-of gs)))
 
 (defn- -seqable-gen [schema options]
-  (let [el (-> schema m/children first)]
+  (let [{:keys [min]} (-min-max schema options)
+        el (-> schema m/children first)]
     (gen-one-of
-     (-> [nil-gen]
+     (-> []
+         (cond->
+           (or (nil? min) (zero? min))
+           (conj nil-gen))
          (into (map #(-coll-gen schema % options))
                [identity vec eduction #(into-array #?(:clj Object) %)])
          (conj (-coll-distinct-gen schema set options))

test/malli/generator_test.cljc

@@ -1137,3 +1137,9 @@
                   [{} :map]]]
       (is (every? #{{:type nil} {:type {}}} (mg/sample schema)))
       (is (every? (m/validator schema) (mg/sample schema))))))
+
+(deftest seqable-generates-non-empty-with-positive-min-test
+  (is (seq (mg/generate [:seqable {:min 4 :max 4} :int] {:seed 0})))
+  (doseq [_ (range 100)
+          v (mg/sample [:seqable {:min 1} :any])]
+    (is (seq v))))