add test to verify network exception is cought on init of coinmarketcap

freqtrade/tests/test_fiat_convert.py

@@ -6,6 +6,8 @@ from unittest.mock import MagicMock
 
 import pytest
 
+from requests.exceptions import RequestException
+
 from freqtrade.fiat_convert import CryptoFiat, CryptoToFiatConverter
 from freqtrade.tests.conftest import patch_coinmarketcap
 
@@ -133,6 +135,21 @@ def test_loadcryptomap(mocker):
     assert fiat_convert._cryptomap["BTC"] == "1"
 
 
+def test_fiat_init_network_exception(mocker):
+    # Because CryptoToFiatConverter is a Singleton we reset the listings
+    listmock = MagicMock(side_effect=RequestException)
+    mocker.patch.multiple(
+        'freqtrade.fiat_convert.Market',
+        listings=listmock,
+    )
+    # with pytest.raises(RequestEsxception):
+    fiat_convert = CryptoToFiatConverter()
+    fiat_convert._cryptomap = {}
+    fiat_convert._load_cryptomap()
+
+    assert len(fiat_convert._cryptomap) == 0
+
+
 def test_fiat_convert_without_network():
     # Because CryptoToFiatConverter is a Singleton we reset the value of _coinmarketcap