Replace 'BTC_XXX' with 'XXX/BTC' for pairs and 'XXX_BTC' for files

freqtrade/tests/testdata/download_backtest_data.py

@@ -10,10 +10,10 @@ from freqtrade import misc
 
 parser = misc.common_args_parser('download utility')
 parser.add_argument(
-        '-p', '--pair',
-        help='JSON file containing pairs to download',
-        dest='pair',
-        default=None
+    '-p', '--pair',
+    help='JSON file containing pairs to download',
+    dest='pair',
+    default=None
 )
 args = parser.parse_args(sys.argv[1:])
 
@@ -34,5 +34,6 @@ for pair in PAIRS:
     for tick_interval in TICKER_INTERVALS:
         print('downloading pair %s, interval %s' % (pair, tick_interval))
         data = exchange.get_ticker_history(pair, tick_interval)
-        filename = '{}-{}.json'.format(pair, tick_interval)
+        pair_print = pair.replace('/', '_')
+        filename = '{}-{}.json'.format(pair_print, tick_interval)
         misc.file_dump_json(filename, data)