TST: 26807 split pandas/tests/tseries/offsets/test_offsets.py into multiple smaller test modules

pandas/tests/tseries/offsets/common.py

@@ -1,6 +1,24 @@
 """
-Assertion helpers for offsets tests
+Assertion helpers and base class for offsets tests
 """
+from datetime import datetime
+from typing import Optional, Type
+
+from dateutil.tz.tz import tzlocal
+import pytest
+
+from pandas._libs.tslibs import OutOfBoundsDatetime, Timestamp
+from pandas._libs.tslibs.offsets import (
+    FY5253,
+    BusinessHour,
+    CustomBusinessHour,
+    DateOffset,
+    FY5253Quarter,
+    LastWeekOfMonth,
+    Week,
+    WeekOfMonth,
+)
+from pandas.compat import IS64
 
 
 def assert_offset_equal(offset, base, expected):
@@ -24,3 +42,156 @@ def assert_is_on_offset(offset, date, expected):
         f"\nExpected: {expected}\nActual: {actual}\nFor Offset: {offset})"
         f"\nAt Date: {date}"
     )
+
+
+class WeekDay:
+    MON = 0
+    TUE = 1
+    WED = 2
+    THU = 3
+    FRI = 4
+    SAT = 5
+    SUN = 6
+
+
+class Base:
+    _offset: Optional[Type[DateOffset]] = None
+    d = Timestamp(datetime(2008, 1, 2))
+
+    timezones = [
+        None,
+        "UTC",
+        "Asia/Tokyo",
+        "US/Eastern",
+        "dateutil/Asia/Tokyo",
+        "dateutil/US/Pacific",
+    ]
+
+    def _get_offset(self, klass, value=1, normalize=False):
+        # create instance from offset class
+        if klass is FY5253:
+            klass = klass(
+                n=value,
+                startingMonth=1,
+                weekday=1,
+                variation="last",
+                normalize=normalize,
+            )
+        elif klass is FY5253Quarter:
+            klass = klass(
+                n=value,
+                startingMonth=1,
+                weekday=1,
+                qtr_with_extra_week=1,
+                variation="last",
+                normalize=normalize,
+            )
+        elif klass is LastWeekOfMonth:
+            klass = klass(n=value, weekday=5, normalize=normalize)
+        elif klass is WeekOfMonth:
+            klass = klass(n=value, week=1, weekday=5, normalize=normalize)
+        elif klass is Week:
+            klass = klass(n=value, weekday=5, normalize=normalize)
+        elif klass is DateOffset:
+            klass = klass(days=value, normalize=normalize)
+        else:
+            klass = klass(value, normalize=normalize)
+        return klass
+
+    def test_apply_out_of_range(self, tz_naive_fixture):
+        tz = tz_naive_fixture
+        if self._offset is None:
+            return
+        if isinstance(tz, tzlocal) and not IS64:
+            pytest.xfail(reason="OverflowError inside tzlocal past 2038")
+
+        # try to create an out-of-bounds result timestamp; if we can't create
+        # the offset skip
+        try:
+            if self._offset in (BusinessHour, CustomBusinessHour):
+                # Using 10000 in BusinessHour fails in tz check because of DST
+                # difference
+                offset = self._get_offset(self._offset, value=100000)
+            else:
+                offset = self._get_offset(self._offset, value=10000)
+
+            result = Timestamp("20080101") + offset
+            assert isinstance(result, datetime)
+            assert result.tzinfo is None
+
+            # Check tz is preserved
+            t = Timestamp("20080101", tz=tz)
+            result = t + offset
+            assert isinstance(result, datetime)
+            assert t.tzinfo == result.tzinfo
+
+        except OutOfBoundsDatetime:
+            pass
+        except (ValueError, KeyError):
+            # we are creating an invalid offset
+            # so ignore
+            pass
+
+    def test_offsets_compare_equal(self):
+        # root cause of GH#456: __ne__ was not implemented
+        if self._offset is None:
+            return
+        offset1 = self._offset()
+        offset2 = self._offset()
+        assert not offset1 != offset2
+        assert offset1 == offset2
+
+    def test_rsub(self):
+        if self._offset is None or not hasattr(self, "offset2"):
+            # i.e. skip for TestCommon and YQM subclasses that do not have
+            # offset2 attr
+            return
+        assert self.d - self.offset2 == (-self.offset2).apply(self.d)
+
+    def test_radd(self):
+        if self._offset is None or not hasattr(self, "offset2"):
+            # i.e. skip for TestCommon and YQM subclasses that do not have
+            # offset2 attr
+            return
+        assert self.d + self.offset2 == self.offset2 + self.d
+
+    def test_sub(self):
+        if self._offset is None or not hasattr(self, "offset2"):
+            # i.e. skip for TestCommon and YQM subclasses that do not have
+            # offset2 attr
+            return
+        off = self.offset2
+        msg = "Cannot subtract datetime from offset"
+        with pytest.raises(TypeError, match=msg):
+            off - self.d
+
+        assert 2 * off - off == off
+        assert self.d - self.offset2 == self.d + self._offset(-2)
+        assert self.d - self.offset2 == self.d - (2 * off - off)
+
+    def testMult1(self):
+        if self._offset is None or not hasattr(self, "offset1"):
+            # i.e. skip for TestCommon and YQM subclasses that do not have
+            # offset1 attr
+            return
+        assert self.d + 10 * self.offset1 == self.d + self._offset(10)
+        assert self.d + 5 * self.offset1 == self.d + self._offset(5)
+
+    def testMult2(self):
+        if self._offset is None:
+            return
+        assert self.d + (-5 * self._offset(-10)) == self.d + self._offset(50)
+        assert self.d + (-3 * self._offset(-2)) == self.d + self._offset(6)
+
+    def test_compare_str(self):
+        # GH#23524
+        # comparing to strings that cannot be cast to DateOffsets should
+        #  not raise for __eq__ or __ne__
+        if self._offset is None:
+            return
+        off = self._get_offset(self._offset)
+
+        assert not off == "infer"
+        assert off != "foo"
+        # Note: inequalities are only implemented for Tick subclasses;
+        #  tests for this are in test_ticks