[settings] Set PLOTTERS_ROOT properly

beat/web/settings/test.py

@@ -49,6 +49,7 @@ LOGGING['loggers']['beat.core']['handlers'] = ['discard']
 
 PREFIX = os.path.realpath('./test_prefix')
 ALGORITHMS_ROOT  = os.path.join(PREFIX, 'algorithms')
+PLOTTERS_ROOT    = os.path.join(PREFIX, 'plotters')
 LIBRARIES_ROOT   = os.path.join(PREFIX, 'libraries')
 DATABASES_ROOT   = os.path.join(PREFIX, 'databases')
 DATAFORMATS_ROOT = os.path.join(PREFIX, 'dataformats')