Fix valueerror in case of empty array files

freqtrade/data/history/jsondatahandler.py

@@ -86,8 +86,12 @@ class JsonDataHandler(IDataHandler):
         filename = self._pair_data_filename(self._datadir, pair, timeframe)
         if not filename.exists():
             return DataFrame(columns=self._columns)
-        pairdata = read_json(filename, orient='values')
-        pairdata.columns = self._columns
+        try:
+            pairdata = read_json(filename, orient='values')
+            pairdata.columns = self._columns
+        except ValueError:
+            logger.error(f"Could not load data for {pair}.")
+            return DataFrame(columns=self._columns)
         pairdata = pairdata.astype(dtype={'open': 'float', 'high': 'float',
                                           'low': 'float', 'close': 'float', 'volume': 'float'})
         pairdata['date'] = to_datetime(pairdata['date'],

tests/commands/test_commands.py

@@ -1181,7 +1181,7 @@ def test_start_list_data(testdatadir, capsys):
     pargs['config'] = None
     start_list_data(pargs)
     captured = capsys.readouterr()
-    assert "Found 16 pair / timeframe combinations." in captured.out
+    assert "Found 17 pair / timeframe combinations." in captured.out
     assert "\n|         Pair |       Timeframe |\n" in captured.out
     assert "\n| UNITTEST/BTC | 1m, 5m, 8m, 30m |\n" in captured.out
 

tests/data/test_history.py

@@ -646,7 +646,7 @@ def test_datahandler_ohlcv_get_available_data(testdatadir):
                               ('ZEC/BTC', '5m'), ('UNITTEST/BTC', '1m'), ('ADA/BTC', '5m'),
                               ('ETC/BTC', '5m'), ('NXT/BTC', '5m'), ('DASH/BTC', '5m'),
                               ('XRP/ETH', '1m'), ('XRP/ETH', '5m'), ('UNITTEST/BTC', '30m'),
-                              ('UNITTEST/BTC', '8m')}
+                              ('UNITTEST/BTC', '8m'), ('NOPAIR/XXX', '4m')}
 
     paircombs = JsonGzDataHandler.ohlcv_get_available_data(testdatadir)
     assert set(paircombs) == {('UNITTEST/BTC', '8m')}
@@ -672,6 +672,18 @@ def test_jsondatahandler_ohlcv_purge(mocker, testdatadir):
     assert unlinkmock.call_count == 1
 
 
+def test_jsondatahandler_ohlcv_load(testdatadir, caplog):
+    dh = JsonDataHandler(testdatadir)
+    df = dh.ohlcv_load('XRP/ETH', '5m')
+    assert len(df) == 711
+
+    # Failure case (empty array)
+    df1 = dh.ohlcv_load('NOPAIR/XXX', '4m')
+    assert len(df1) == 0
+    assert log_has("Could not load data for NOPAIR/XXX.", caplog)
+    assert df.columns.equals(df1.columns)
+
+
 def test_jsondatahandler_trades_load(testdatadir, caplog):
     dh = JsonGzDataHandler(testdatadir)
     logmsg = "Old trades format detected - converting"

tests/rpc/test_rpc_apiserver.py

@@ -1109,7 +1109,7 @@ def test_list_available_pairs(botclient):
     rc = client_get(client, f"{BASE_URI}/available_pairs")
 
     assert_response(rc)
-    assert rc.json()['length'] == 12
+    assert rc.json()['length'] == 13
     assert isinstance(rc.json()['pairs'], list)
 
     rc = client_get(client, f"{BASE_URI}/available_pairs?timeframe=5m")

tests/testdata/NOPAIR_XXX-4m.json

@@ -0,0 +1 @@
+[]