diff --git a/.gitignore b/.gitignore
index 6612da5..c28ec7e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,7 +3,6 @@ vendor
 
 #temp files
 cache/*
-test.php
 newssync.db*
 
 # Windows image file caches
diff --git a/lib/Database.php b/lib/Database.php
index 268614d..6ff36c5 100644
--- a/lib/Database.php
+++ b/lib/Database.php
@@ -341,12 +341,19 @@ class Database {
         } else {
             // if a parent is specified, make sure it exists and belongs to the user; get its root (first-level) folder if it's a nested folder
             $p = $this->db->prepare("SELECT id,root from newssync_folders where owner is ? and id is ?", "str", "int")->run($user, $parent)->getRow();
-            if($p===null) {
+            if(!$p) {
                 throw new Db\ExceptionInput("idMissing", ["action" => __FUNCTION__, "field" => "parent", 'id' => $parent]);
             } else {
                 // if the parent does not have a root specified (because it is a first-level folder) use the parent ID as the root ID
                 $root = $p['root']===null ? $parent : $p['root'];
             }
         }
+        // check if a folder by the same name already exists, because nulls are wonky in SQL
+        // FIXME: How should folder name be compared? Should a Unicode normalization be applied before comparison and insertion?
+        if($this->db->prepare("SELECT count(*) from newssync_folders where owner is ? and parent is ? and name is ?", "str", "int", "str")->run($user, $parent, $data['name'])->getValue() > 0) {
+            throw new Db\ExceptionInput("constraintViolation"); // FIXME: There needs to be a practical message here
+        }
+        // actually perform the insert (!)
+        return $this->db->prepare("INSERT INTO newssync_folders(owner,parent,root,name) values(?,?,?,?)", "str", "int", "int", "str")->run($user, $parent, $root, $data['name'])->lastId();
     }
 }
\ No newline at end of file
diff --git a/sql/SQLite3/0.sql b/sql/SQLite3/0.sql
index aaf8e82..eefcb9a 100644
--- a/sql/SQLite3/0.sql
+++ b/sql/SQLite3/0.sql
@@ -53,8 +53,8 @@ create table newssync_subscriptions(
 create table newssync_folders(
     id integer primary key not null,                                                                        -- sequence number
     owner TEXT not null references newssync_users(id) on delete cascade on update cascade,                  -- owner of folder
-    parent integer not null default 0,                                                                      -- parent folder id
-    root integer not null default 0,                                                                        -- first-level folder (ownCloud folder)
+    parent integer default null,                                                                            -- parent folder id
+    root integer default null,                                                                              -- first-level folder (ownCloud folder)
     name TEXT not null,                                                                                     -- folder name
     modified datetime not null default CURRENT_TIMESTAMP,                                                   --
     unique(owner,name,parent)                                                                               -- cannot have multiple folders with the same name under the same parent for the same owner
diff --git a/tests/test.php b/tests/test.php
new file mode 100644
index 0000000..9531bfa
--- /dev/null
+++ b/tests/test.php
@@ -0,0 +1,24 @@
+<?php
+namespace JKingWeb\NewsSync;
+const INSTALL = true;
+require_once "../bootstrap.php";
+
+
+$user = "john.doe@example.com";
+$pass = "secret";
+$_SERVER['PHP_AUTH_USER'] = $user;
+$_SERVER['PHP_AUTH_PW'] = $pass;
+$conf = new Conf();
+$conf->dbSQLite3File = ":memory:";
+$conf->userAuthPreferHTTP = true;
+$data = new RuntimeData($conf);
+$data->db->schemaUpdate();
+
+
+$data->user->add($user, $pass);
+$data->user->auth();
+$data->user->authorizationEnabled(false);
+$data->user->rightsSet($user, User\Driver::RIGHTS_GLOBAL_ADMIN);
+$data->user->authorizationEnabled(true);
+$data->db->folderAdd($user, ['name' => 'ook']);
+$data->db->subscriptionAdd($user, "http://www.tbray.org/ongoing/ongoing.atom");
\ No newline at end of file