Remove in-house long time interval checking.

cf_units/__init__.py

@@ -964,36 +964,6 @@ def is_time_reference(self):
         """
         return self.calendar is not None
 
-    def is_long_time_interval(self):
-        """
-        Defines whether this unit describes a time unit with a long time
-        interval ("months" or "years"). These long time intervals *are*
-        supported by `UDUNITS2` but are not supported by `cftime`. This
-        discrepancy means we cannot run self.num2date() on a time unit with
-        a long time interval.
-
-        Returns:
-            Boolean.
-
-        For example:
-
-            >>> import cf_units
-            >>> u = cf_units.Unit('days since epoch')
-            >>> u.is_long_time_interval()
-            False
-            >>> u = cf_units.Unit('years since epoch')
-            >>> u.is_long_time_interval()
-            True
-
-        """
-        result = False
-        long_time_intervals = ["year", "month"]
-        if self.is_time_reference():
-            result = any(
-                interval in self.origin for interval in long_time_intervals
-            )
-        return result
-
     def title(self, value):
         """
         Return the unit value as a title string.
@@ -1929,15 +1899,6 @@ def cftime_unit(self):
         if self.calendar is None:
             raise ValueError("Unit has undefined calendar")
 
-        # `cftime` cannot parse long time intervals ("months" or "years").
-        if self.is_long_time_interval():
-            interval = self.origin.split(" ")[0]
-            emsg = (
-                'Time units with interval of "months", "years" '
-                '(or singular of these) cannot be processed, got "{!s}".'
-            )
-            raise ValueError(emsg.format(interval))
-
         #
         # ensure to strip out non-parsable 'UTC' postfix, which
         # is generated by UDUNITS-2 formatted output

cf_units/tests/integration/test_date2num.py

@@ -8,7 +8,6 @@
 import datetime
 
 import numpy as np
-import pytest
 
 from cf_units import date2num
 
@@ -60,11 +59,3 @@ def test_discard_microsecond(self):
         res = date2num(date, self.unit, self.calendar)
 
         assert exp == res
-
-    def test_long_time_interval(self):
-        # This test should fail with an error that we need to catch properly.
-        unit = "years since 1970-01-01"
-        date = datetime.datetime(1970, 1, 1, 0, 0, 5)
-        exp_emsg = 'interval of "months", "years" .* got "years".'
-        with pytest.raises(ValueError, match=exp_emsg):
-            date2num(date, unit, self.calendar)

cf_units/tests/unit/unit/test_Unit.py

@@ -56,11 +56,6 @@ def test_no_change(self):
         # the same object.
         assert result is not u
 
-    def test_long_time_interval(self):
-        u = Unit("months since 1970-01-01", calendar="standard")
-        with pytest.raises(ValueError, match="cannot be processed"):
-            u.change_calendar("proleptic_gregorian")
-
     def test_wrong_calendar(self):
         u = Unit("days since 1900-01-01", calendar="360_day")
         with pytest.raises(
@@ -273,31 +268,6 @@ def test_type_conversion(self):
         np.testing.assert_array_almost_equal(self.rads_array, result)
 
 
-class Test_is_long_time_interval:
-    def test_short_time_interval(self):
-        # A short time interval is a time interval from seconds to days.
-        unit = Unit("seconds since epoch")
-        result = unit.is_long_time_interval()
-        assert not result
-
-    def test_long_time_interval(self):
-        # A long time interval is a time interval of months or years.
-        unit = Unit("months since epoch")
-        result = unit.is_long_time_interval()
-        assert result
-
-    def test_calendar(self):
-        # Check that a different calendar does not affect the result.
-        unit = Unit("months since epoch", calendar=cf_units.CALENDAR_360_DAY)
-        result = unit.is_long_time_interval()
-        assert result
-
-    def test_not_time_unit(self):
-        unit = Unit("K")
-        result = unit.is_long_time_interval()
-        assert not result
-
-
 class Test_format:
     def test_invalid_ut_unit(self):
         # https://github.com/SciTools/cf-units/issues/133 flagged up that