New test-query that does not violate any foreign key contraints

installer/test.php

@@ -120,12 +120,12 @@ if ($db_working) {
 // more database tests
 if ($db_working) {
     // write test
-    $db_write = $DB->query("INSERT INTO {$RCI->config['db_table_cache']} (session_id, cache_key, data, user_id) VALUES (?, ?, ?, 0)", '1234567890abcdef', 'test', 'test');
-    $insert_id = $DB->insert_id($RCI->config['db_sequence_cache']);
-    
-    if ($db_write && $insert_id) {
+    $insert_id = md5(uniqid());
+    $db_write = $DB->query("INSERT INTO {$RCI->config['db_table_session']} (sess_id, created, ip, vars) VALUES (?, ".$DB->now().", '127.0.0.1', 'foo')", $insert_id);
+
+    if ($db_write) {
       $RCI->pass('DB Write');
-      $DB->query("DELETE FROM {$RCI->config['db_table_cache']} WHERE cache_id=?", $insert_id);
+      $DB->query("DELETE FROM {$RCI->config['db_table_session']} WHERE sess_id=?", $insert_id);
     }
     else {
       $RCI->fail('DB Write', $RCI->get_error());