Add end_month and end_day feature to setup_fiscal_calendar

fiscalyear.py

@@ -29,6 +29,73 @@
 START_DAY = 1
 
 
+def _check_only_start_or_end_present(start_month, start_day,
+                                     end_month, end_day):
+    """Checks that only start_* or end_* are present.
+
+    :param start_month: The first month of the fiscal year
+    :param start_day: The first day of the first month of the fiscal year
+    :param end_month: The last month of the fiscal year
+    :param end_day: The last day of the last month of the fiscal year
+    :raises ValueError: If ``start_month`` and/or ``start_day`` is passed
+        along with  ``end_month`` and/or ``end_day``
+    """
+    start_present = start_month is not None or start_day is not None
+    end_present = end_month is not None or end_day is not None
+    if start_present and end_present:
+        emsg = "invalid combination of " + \
+            "start_month, start_day, end_month, end_day; " + \
+            "pass either start_* or end_*"
+        raise ValueError(emsg)
+
+
+def _start_day_from_end(end_month, end_day):
+    """Returns start day from end month and day.
+
+    :param end_month: The last month of the fiscal year
+    :type end_month: int or str
+    :param end_day: The last day of the last month of the fiscal year
+    :type end_day: int or str
+    :raises ValueError: If ``end_month`` or ``end_day`` is not an int or
+        int-like string
+    :raises ValueError: If ``end_month`` or ``end_day`` is out of range
+    """
+    day = _check_day(end_month, end_day) + 1
+    max_day = calendar.monthrange(2001, end_month)[1]
+    start_day = 1 if day > max_day else day
+    return start_day
+
+
+def _start_month_day_from_end(end_month, end_day):
+    """Returns start month and day from end month and day.
+
+    :param end_month: The last month of the fiscal year
+    :type end_month: int or str
+    :param end_day: The last day of the last month of the fiscal year
+    :type end_day: int or str
+    :raises ValueError: If ``end_month`` or ``end_day`` is not an int or
+        int-like string
+    :raises ValueError: If ``end_month`` or ``end_day`` is out of range
+    """
+    if end_month is None and end_day is None:
+        start_day = None
+        start_month = None
+    elif end_month is None:
+        month = 12 if START_MONTH == 1 else START_MONTH - 1
+        start_day = _start_day_from_end(month, end_day)
+        start_month = None
+    elif end_day is None:
+        start_day = None
+        start_month = _check_month(end_month) % 12 + 1
+    else:
+        day = _check_day(end_month, end_day)
+        month = _check_month(end_month)
+        start_day = _start_day_from_end(month, day)
+        start_month = month if start_day > day else month % 12 + 1
+
+    return start_month, start_day
+
+
 def _validate_fiscal_calendar_params(start_year, start_month, start_day):
     """Raise an Exception if the calendar parameters are invalid.
 
@@ -53,8 +120,9 @@ def _validate_fiscal_calendar_params(start_year, start_month, start_day):
     _check_day(start_month, start_day)
 
 
-def setup_fiscal_calendar(start_year=None, start_month=None, start_day=None):
-    """Modify the start of the fiscal calendar.
+def setup_fiscal_calendar(start_year=None, start_month=None, start_day=None,
+                          end_month=None, end_day=None):
+    """Modify the fiscal calendar.
 
     :param start_year: Relationship between the start of the fiscal year and
         the calendar year. Possible values: ``'previous'`` or ``'same'``.
@@ -63,13 +131,24 @@ def setup_fiscal_calendar(start_year=None, start_month=None, start_day=None):
     :type start_month: int or str
     :param start_day: The first day of the first month of the fiscal year
     :type start_day: int or str
+    :param end_month: The last month of the fiscal year
+    :type end_month: int or str
+    :param end_day: The last day of the last month of the fiscal year
+    :type end_day: int or str
     :raises ValueError: If ``start_year`` is not ``'previous'`` or ``'same'``
     :raises TypeError: If ``start_month`` or ``start_day`` is not an int or
         int-like string
     :raises ValueError: If ``start_month`` or ``start_day`` is out of range
+    :raises ValueError: If ``start_month`` and/or ``start_day`` is passed
+        along with  ``end_month`` and/or ``end_day``
     """
     global START_YEAR, START_MONTH, START_DAY
 
+    _check_only_start_or_end_present(start_month, start_day, end_month, end_day)
+
+    if start_month is None and start_day is None:
+        start_month, start_day = _start_month_day_from_end(end_month, end_day)
+
     # If arguments are omitted, use the currently active values.
     start_year = START_YEAR if start_year is None else start_year
     start_month = START_MONTH if start_month is None else start_month

test_fiscalyear.py

@@ -147,6 +147,124 @@ def test_valid_input(self, arguments):
         fiscalyear._validate_fiscal_calendar_params(**arguments)
 
 
+class TestCheckOnlyStartOrEndPresent(object):
+    @pytest.mark.parametrize(
+        "arguments, exception",
+        [
+            (dict(start_month=None, start_day=1, end_month=12, end_day=31),
+             ValueError),
+            (dict(start_month=1, start_day=None, end_month=12, end_day=31),
+             ValueError),
+            (dict(start_month=1, start_day=1, end_month=None, end_day=31),
+             ValueError),
+            (dict(start_month=1, start_day=1, end_month=12, end_day=None),
+             ValueError),
+            (dict(start_month=None, start_day=1, end_month=None, end_day=31),
+             ValueError),
+            (dict(start_month=1, start_day=None, end_month=None, end_day=31),
+             ValueError),
+            (dict(start_month=None, start_day=1, end_month=12, end_day=None),
+             ValueError),
+            (dict(start_month=1, start_day=None, end_month=12, end_day=None),
+             ValueError),
+        ],
+    )
+    def test_invalid_input(self, arguments, exception):
+        with pytest.raises(exception):
+            fiscalyear._check_only_start_or_end_present(**arguments)
+
+    @pytest.mark.parametrize(
+        "arguments",
+        [
+            dict(start_month=None, start_day=None, end_month=12, end_day=31),
+            dict(start_month=None, start_day=None, end_month=4, end_day=30),
+            dict(start_month=None, start_day=None, end_month='12', end_day='31'),
+            dict(start_month=None, start_day=None, end_month='4', end_day='30'),
+            dict(start_month=1, start_day=1, end_month=None, end_day=None),
+            dict(start_month=6, start_day=15, end_month=None, end_day=None),
+            dict(start_month='1', start_day='1', end_month=None, end_day=None),
+            dict(start_month='6', start_day='15', end_month=None, end_day=None),
+            dict(start_month=None, start_day=None, end_month=None, end_day=None),
+        ],
+    )
+    def test_valid_input(self, arguments):
+        fiscalyear._check_only_start_or_end_present(**arguments)
+
+
+class TestStartDayFromEndParams(object):
+    @pytest.mark.parametrize(
+        "arguments, exception",
+        [
+            (dict(end_month="asdf", end_day=1), TypeError),
+            (dict(end_month=float(12), end_day=1), TypeError),
+            (dict(end_month=object(), end_day=1), TypeError),
+            (dict(end_month=-1, end_day=1), ValueError),
+            (dict(end_month=0, end_day=1), ValueError),
+            (dict(end_month=13, end_day=1), ValueError),
+            (dict(end_month=12, end_day="asdf"), TypeError),
+            (dict(end_month=12, end_day=float(1)), TypeError),
+            (dict(end_month=12, end_day=object()), TypeError),
+            (dict(end_month=12, end_day=0), ValueError),
+            (dict(end_month=12, end_day=-1), ValueError),
+            (dict(end_month=12, end_day=32), ValueError),
+        ],
+    )
+    def test_invalid_input(self, arguments, exception):
+        with pytest.raises(exception):
+            fiscalyear._start_month_day_from_end(**arguments)
+
+    @pytest.mark.parametrize(
+        "arguments",
+        [
+            dict(end_month=1, end_day=1),
+            dict(end_month=1, end_day=31),
+            dict(end_month=12, end_day=1),
+            dict(end_month='1', end_day='1'),
+            dict(end_month='1', end_day='31'),
+            dict(end_month='12', end_day='1'),
+        ],
+    )
+    def test_valid_input(self, arguments):
+        fiscalyear._start_month_day_from_end(**arguments)
+
+
+class TestStartMonthDayFromEndParams(object):
+    @pytest.mark.parametrize(
+        "arguments, exception",
+        [
+            (dict(end_month="asdf", end_day=1), TypeError),
+            (dict(end_month=float(12), end_day=1), TypeError),
+            (dict(end_month=object(), end_day=1), TypeError),
+            (dict(end_month=-1, end_day=1), ValueError),
+            (dict(end_month=0, end_day=1), ValueError),
+            (dict(end_month=13, end_day=1), ValueError),
+            (dict(end_month=12, end_day="asdf"), TypeError),
+            (dict(end_month=12, end_day=float(1)), TypeError),
+            (dict(end_month=12, end_day=object()), TypeError),
+            (dict(end_month=12, end_day=0), ValueError),
+            (dict(end_month=12, end_day=-1), ValueError),
+            (dict(end_month=12, end_day=32), ValueError),
+        ],
+    )
+    def test_invalid_input(self, arguments, exception):
+        with pytest.raises(exception):
+            fiscalyear._start_month_day_from_end(**arguments)
+
+    @pytest.mark.parametrize(
+        "arguments",
+        [
+            dict(end_month=1, end_day=1),
+            dict(end_month=1, end_day=31),
+            dict(end_month=12, end_day=1),
+            dict(end_month=1, end_day=1),
+            dict(end_month=1, end_day=31),
+            dict(end_month=12, end_day=1),
+        ],
+    )
+    def test_valid_input(self, arguments):
+        fiscalyear._start_month_day_from_end(**arguments)
+
+
 class TestSetupFiscalCalendar(object):
     def test_start_year(self):
         assert fiscalyear.START_YEAR == "previous"
@@ -175,6 +293,41 @@ def test_start_day(self):
 
         assert fiscalyear.START_DAY == 1
 
+    def test_end_month(self):
+        assert fiscalyear.START_MONTH == 10
+
+        fiscalyear.setup_fiscal_calendar(end_month=4)
+        assert fiscalyear.START_MONTH == 5
+        fiscalyear.setup_fiscal_calendar(end_month=12)
+        assert fiscalyear.START_MONTH == 1
+        fiscalyear.setup_fiscal_calendar(end_month=9)
+
+        assert fiscalyear.START_MONTH == 10
+
+    def test_end_day(self):
+        assert fiscalyear.START_DAY == 1
+
+        fiscalyear.setup_fiscal_calendar(end_day=6)
+        assert fiscalyear.START_DAY == 7
+        fiscalyear.setup_fiscal_calendar(end_day=30)
+
+        assert fiscalyear.START_DAY == 1
+
+    def test_end_month_day(self):
+        assert fiscalyear.START_MONTH == 10
+        assert fiscalyear.START_DAY == 1
+
+        fiscalyear.setup_fiscal_calendar(end_month=4, end_day=15)
+        assert fiscalyear.START_MONTH == 4
+        assert fiscalyear.START_DAY == 16
+        fiscalyear.setup_fiscal_calendar(end_month=2, end_day=28)
+        assert fiscalyear.START_MONTH == 3
+        assert fiscalyear.START_DAY == 1
+        fiscalyear.setup_fiscal_calendar(end_month=9, end_day=30)
+
+        assert fiscalyear.START_MONTH == 10
+        assert fiscalyear.START_DAY == 1
+
     def test_complex(self):
         # Test defaults
         day = fiscalyear.FiscalDate(2017, 12, 1)