Clarify DATA_DIR path

common/lib/xmodule/xmodule/tests/__init__.py

@@ -24,10 +24,10 @@ from xmodule.error_module import ErrorDescriptor
 from xmodule.modulestore.xml import LocationReader
 
 
+MODULE_DIR = path(__file__).dirname()
 # Location of common test DATA directory
 # '../../../../edx-platform/common/test/data/'
-MODULE_DIR = path(__file__).dirname()
-DATA_DIR = path.joinpath(*MODULE_DIR.splitall()[:-4]) / 'test/data/'
+DATA_DIR = MODULE_DIR.parent.parent.parent.parent / "test" / "data"
 
 
 open_ended_grading_interface = {