Add tests for lines missing coverage

src/undate/undate.py

@@ -210,12 +210,14 @@ def _comparison_type(self, other: object) -> "Undate":
     def __eq__(self, other: object) -> bool:
         # Note: assumes label differences don't matter for comparing dates
 
-        other = self._comparison_type(other)
-
         # only a day-precision fully known undate can be equal to a datetime.date
         if isinstance(other, datetime.date):
             return self.earliest == other and self.latest == other
 
+        other = self._comparison_type(other)
+        if other is NotImplemented:
+            return NotImplemented
+
         # check for apparent equality
         looks_equal = (
             self.earliest == other.earliest
@@ -346,6 +348,7 @@ def day(self) -> Optional[str]:
         if day:
             return f"{day:>02}"
         # if value is unset but date precision is day, return unknown day
+        # (may not be possible to have day precision with day part set in normal use)
         elif self.precision == DatePrecision.DAY:
             return self.MISSING_DIGIT * 2
         return None

tests/test_undate.py

@@ -2,7 +2,7 @@
 from datetime import date
 
 import pytest
-from undate.date import Timedelta
+from undate.date import DatePrecision, Timedelta
 from undate.undate import Undate, UndateInterval
 
 
@@ -143,6 +143,11 @@ def test_year_property(self):
         # unset year
         assert Undate(month=12, day=31).year == "XXXX"
 
+        # force method to hit conditional for date precision
+        some_century = Undate()
+        some_century.precision = DatePrecision.CENTURY
+        assert some_century.year is None
+
     def test_month_property(self):
         # one, two digit month
         assert Undate(2023, 1).month == "01"
@@ -172,12 +177,20 @@ def test_day_property(self):
         # Day without year or month
         assert Undate(day=15).day == "15"
 
+        # force str based on date precision without day part set
+        someday = Undate(2023)
+        someday.precision = DatePrecision.DAY
+        assert someday.day == "XX"
+
     def test_eq(self):
         assert Undate(2022) == Undate(2022)
         assert Undate(2022, 10) == Undate(2022, 10)
         assert Undate(2022, 10, 1) == Undate(2022, 10, 1)
         assert Undate(month=2, day=7) == Undate(month=2, day=7)
 
+        # something we can't convert for comparison should return NotImplemented
+        assert Undate(2022).__eq__("not a date") == NotImplemented
+
     def test_eq_datetime_date(self):
         # support comparisons with datetime objects for full day-precision
         assert Undate(2022, 10, 1) == date(2022, 10, 1)
@@ -535,3 +548,7 @@ def test_duration(self):
 
         # duration is not supported for open-ended intervals
         assert UndateInterval(Undate(2000), None).duration() == NotImplemented
+
+        # one year set and the other not currently raises not implemented error
+        with pytest.raises(NotImplementedError):
+            UndateInterval(Undate(2000), Undate()).duration()