Make listOf able to take a min/max length of list

1 files changed, 13 insertions, 0 deletions

diff --git a/src/main/java/au/id/zancanaro/javacheck/Generators.java b/src/main/java/au/id/zancanaro/javacheck/Generators.java
index bf1b1b3..eab3eed 100644
--- a/src/main/java/au/id/zancanaro/javacheck/Generators.java
+++ b/src/main/java/au/id/zancanaro/javacheck/Generators.java
@@ -80,6 +80,19 @@ public final class Generators {
         };
     }
 
+    public static <T> Generator<List<T>> listOf(Generator<T> gen, int minElements, int maxElements) {
+        return (random, size) -> {
+            Generator<Integer> countGen = sized(s -> integer(minElements, maxElements));
+            int count = countGen.generate(random, size).getValue();
+            return Generator.list(count, gen).generate(random, size)
+                    .filter(list ->
+                            minElements <= list.size()
+                                    && list.size() < maxElements);
+        };
+    }
+
+    ;
+
     public static <T> Generator<List<T>> listOf(Generator<T> gen) {
         return (random, size) -> {
             Generator<Integer> countGen = sized(s -> integer(0, s));