[settings] Add helper methods to determine db and prefix path for tests

These will return the paths based on whether it's a CI run
or a standard run.

beat/web/settings/__init__.py

+#!/usr/bin/env python
+# vim: set fileencoding=utf-8 :
+
+###############################################################################
+#                                                                             #
+# Copyright (c) 2020 Idiap Research Institute, http://www.idiap.ch/           #
+# Contact: beat.support@idiap.ch                                              #
+#                                                                             #
+# This file is part of the beat.web module of the BEAT platform.              #
+#                                                                             #
+# Commercial License Usage                                                    #
+# Licensees holding valid commercial BEAT licenses may use this file in       #
+# accordance with the terms contained in a written agreement between you      #
+# and Idiap. For further information contact tto@idiap.ch                     #
+#                                                                             #
+# Alternatively, this file may be used under the terms of the GNU Affero      #
+# Public License version 3 as published by the Free Software and appearing    #
+# in the file LICENSE.AGPL included in the packaging of this file.            #
+# The BEAT platform is distributed in the hope that it will be useful, but    #
+# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY  #
+# or FITNESS FOR A PARTICULAR PURPOSE.                                        #
+#                                                                             #
+# You should have received a copy of the GNU Affero Public License along      #
+# with the BEAT platform. If not, see http://www.gnu.org/licenses/.           #
+#                                                                             #
+###############################################################################
+
+import os
+import platform
+
+
+SHM_PATH = "/dev/shm/beatweb"  # nosec
+
+
+def get_test_db_path(is_on_ci):
+    database_name = "test.sqlite3"
+    database_path = os.path.realpath("./")
+
+    if not is_on_ci:
+        if platform.system() == "Linux":
+            database_path = SHM_PATH
+            if not os.path.exists(database_path):
+                os.makedirs(database_path)
+
+    return os.path.join(database_path, database_name)
+
+
+def get_test_prefix_path(is_on_ci):
+    prefix_path = os.path.realpath("./test_prefix")
+    if not is_on_ci:
+        if platform.system() == "Linux":
+            prefix_path = os.path.join(SHM_PATH, "test_prefix")  # nosec
+
+    return prefix_path