db: create test for get_random_users

src/db/tests/mod.rs

@@ -174,3 +174,11 @@ async fn test_drop_media_except() {
 
     let _ = db.drop_media(literal).await.unwrap();
 }
+
+#[tokio::test]
+async fn test_get_random_users() {
+    let mut db = setup_db().await;
+
+    let users = db.get_random_users(1).await.unwrap();
+    assert_eq!(users.len(), 1);
+}