add test

src/collection/hashset.scad

@@ -44,7 +44,7 @@ function hashset_del(set, elem, hash = df_hash, eq = df_eq) =
 		leng = len(bucket)
 	)
 	leng == 0 ? set :
-	let(i = _find(bucket, elem, eq, leng), _ = echo(i))
+	let(i = _find(bucket, elem, eq, leng))
 	i == -1 ? set : 
 	concat(
 	    slice(set, 0, bidx), 

test/collection/test_hashset.scad

@@ -0,0 +1,18 @@
+use <unittest.scad>;
+use <collection/hashset.scad>;
+
+module test_hashset() {
+    echo("==== test_hashset ====");
+
+    s = hashset([1, 2, 3, 4, 5, 2, 3, 5]);
+    assert(hashset_list(s) == [1, 2, 3, 4, 5]);
+
+    s2 = hashset_add(s, 9);
+    assert(hashset_list(s2) == [1, 2, 3, 4, 5, 9]);
+
+    assert(!hashset_has(s2, 13));
+
+    assert(hashset_list(hashset_del(s2, 2)) == [1, 3, 4, 5, 9]);
+}
+
+test_hashset();