Remove unnecessary class from helpers.file_utils

A class which keeps track of temporary files and removes them
automatically when they're not needed anymore might be a good idea,
but this implementation didn't remove files in some cases. Adding
unrelated methods that could as well be just standalone functions
is bad design, too.

In this case, it's better to just get rid of it altogether instead
of fixing it, since Python 3 has a TemporaryDirectory class, which
can be used for the same purpose and is definitely more
battle-tested.

tests/helpers/server_utils.py

@@ -1,33 +1,29 @@
 # -*- coding: utf-8 -*-
-import logging
 import ConfigParser
+import logging
+import os
+import shutil
+import tempfile
 
 from ankisyncd.sync_app import SyncApp, SyncCollectionHandler, SyncMediaHandler
-from helpers.file_utils import FileUtils
 
 
 class ServerUtils(object):
-    def __init__(self):
-        self.fileutils = FileUtils()
-
     def clean_up(self):
-        self.fileutils.clean_up()
+        shutil.rmtree(self.dir)
 
     def create_server_paths(self):
         """
         Creates temporary files and dirs for our app to use during tests.
         """
+        dir = tempfile.mkdtemp(prefix="ServerUtils")
+        self.dir = dir
+        os.mkdir(os.path.join(dir, "data"))
 
-        auth = self.fileutils.create_file_path(suffix='.db',
-                                               prefix='ankiserver_auth_db_')
-        session = self.fileutils.create_file_path(suffix='.db',
-                                                  prefix='ankiserver_session_db_')
-        data = self.fileutils.create_dir(suffix='',
-                                         prefix='ankiserver_data_root_')
         return {
-            "auth_db": auth,
-            "session_db": session,
-            "data_root": data
+            "auth_db": os.path.join(dir, "auth.db"),
+            "session_db": os.path.join(dir, "session.db"),
+            "data_root": os.path.join(dir, "data"),
         }
 
     @staticmethod