Merge pull request #7 from gilles-crealp/bug-begin-value

Correction of the beginning value

Author: dapper91

crontools/crontab.py

@@ -2,6 +2,7 @@
 import dataclasses as dc
 import datetime as dt
 import heapq
+from math import ceil
 import operator as op
 import tzlocal
 from typing import Any, ClassVar, Dict, Generic, Iterator, Iterable, Optional, Type, TypeVar, Tuple
@@ -141,7 +142,8 @@ def iter(self, start_from: Optional[int] = None) -> Iterator[int]:
         step = 1 if self.step is None else self.step
 
         if start_from is not None:
-            begin = max(begin, start_from)
+            steps = ceil(max(start_from - begin, 0) / step)
+            begin = begin + steps * step
 
         return iter(range(begin, end + 1, step))
 

tests/test_crontab.py

@@ -226,24 +226,54 @@ def test_cron_str(expr, seconds_ext, year_ext):
 @pytest.mark.parametrize(
     'expr, Field, result, start_from',
     [
+        (
+            '*/10',
+            SecondsField,
+            [0, 10, 20, 30, 40, 50],
+            None,
+        ),
+        (
+            '*/10',
+            SecondsField,
+            [20, 30, 40, 50],
+            15,
+        ),
         (
             '*/10',
             MinuteField,
             [0, 10, 20, 30, 40, 50],
             None,
         ),
+        (
+            '*/10',
+            MinuteField,
+            [20, 30, 40, 50],
+            15,
+        ),
         (
             '1,2,5,10-20/2,13,40,40',
             MinuteField,
             [1, 2, 5, 10, 12, 13, 14, 16, 18, 20, 40],
             None,
         ),
+        (
+            '1,2,5,10-20/2,13,40,40',
+            MinuteField,
+            [5, 10, 12, 13, 14, 16, 18, 20, 40],
+            3,
+        ),
         (
             '8-23',
             HourField,
             [20, 21, 22, 23],
             20,
         ),
+        (
+            '*/12',
+            HourField,
+            [12],
+            5,
+        ),
         (
             '*',
             MonthdayField,