Add tests for timerange modifications

tests/test_timerange.py

@@ -1,10 +1,11 @@
 # pragma pylint: disable=missing-docstring, C0103
+import arrow
 import pytest
 
 from freqtrade.configuration import TimeRange
 
 
-def test_parse_timerange_incorrect() -> None:
+def test_parse_timerange_incorrect():
 
     assert TimeRange('date', None, 1274486400, 0) == TimeRange.parse_timerange('20100522-')
     assert TimeRange(None, 'date', 0, 1274486400) == TimeRange.parse_timerange('-20100522')
@@ -28,3 +29,37 @@ def test_parse_timerange_incorrect() -> None:
 
     with pytest.raises(Exception, match=r'Incorrect syntax.*'):
         TimeRange.parse_timerange('-')
+
+
+def test_subtract_start():
+    x = TimeRange('date', 'date', 1274486400, 1438214400)
+    x.subtract_start(300)
+    assert x.startts == 1274486400 - 300
+
+    # Do nothing if no startdate exists
+    x = TimeRange(None, 'date', 0, 1438214400)
+    x.subtract_start(300)
+    assert not x.startts
+
+    x = TimeRange('date', None, 1274486400, 0)
+    x.subtract_start(300)
+    assert x.startts == 1274486400 - 300
+
+
+def test_adjust_start_if_necessary():
+    min_date = arrow.Arrow(2017, 11, 14, 21, 15, 00)
+
+    x = TimeRange('date', 'date', 1510694100, 1510780500)
+    # Adjust by 20 candles - min_date == startts
+    x.adjust_start_if_necessary(300, 20, min_date)
+    assert x.startts == 1510694100 + (20 * 300)
+
+    x = TimeRange('date', 'date', 1510700100, 1510780500)
+    # Do nothing, startupe is set and different min_date
+    x.adjust_start_if_necessary(300, 20, min_date)
+    assert x.startts == 1510694100 + (20 * 300)
+
+    x = TimeRange(None, 'date', 0, 1510780500)
+    # Adjust by 20 candles = 20 * 5m
+    x.adjust_start_if_necessary(300, 20, min_date)
+    assert x.startts == 1510694100 + (20 * 300)