Add unit test for test_file_dump_json()

freqtrade/tests/optimize/test_optimize.py

@@ -3,11 +3,12 @@
 import os
 import json
 import logging
+import uuid
 from shutil import copyfile
 from freqtrade import exchange, optimize
 from freqtrade.exchange import Bittrex
 from freqtrade.optimize.__init__ import make_testdata_path, download_pairs,\
-    download_backtesting_testdata, load_tickerdata_file, trim_tickerlist
+    download_backtesting_testdata, load_tickerdata_file, trim_tickerlist, file_dump_json
 
 # Change this if modifying BTC_UNITEST testdatafile
 _BTC_UNITTEST_LENGTH = 13681
@@ -258,3 +259,28 @@ def test_trim_tickerlist():
     assert ticker_list[0] is not ticker[0]  # The first element should be different
     assert ticker_list[5] is ticker[0]  # The list starts at the index 5
     assert ticker_list[9] is ticker[-1]  # The list ends at the index 9 (5 elements)
+
+
+def test_file_dump_json():
+
+    file = 'freqtrade/tests/testdata/test_{id}.json'.format(id=str(uuid.uuid4()))
+    data = { 'bar': 'foo'}
+
+    # check the file we will create does not exist
+    assert os.path.isfile(file) is False
+
+    # Create the Json file
+    file_dump_json(file, data)
+
+    # Check the file was create
+    assert os.path.isfile(file) is True
+
+    # Open the Json file created and test the data is in it
+    with open(file) as data_file:
+        json_from_file = json.load(data_file)
+
+    assert 'bar' in json_from_file
+    assert json_from_file['bar'] == 'foo'
+
+    # Remove the file
+    _clean_test_file(file)