add test

test/test_all.scad

@@ -74,6 +74,7 @@ include <util/test_some.scad>;
 include <util/test_every.scad>;
 include <util/set/test_hashset.scad>;
 include <util/map/test_hashmap.scad>;
+include <util/test_shuffle.scad>;
 
 // Voxel
 include <voxel/test_vx_line.scad>;

test/util/test_shuffle.scad

@@ -0,0 +1,9 @@
+use <unittest.scad>;
+use <util/shuffle.scad>;
+
+module test_shuffle() {
+    echo("==== test_shuffle ====");
+    assert(shuffle([1, 2, 3, 4], seed = 1) == [3, 1, 4, 2]);
+}
+
+test_shuffle();