Fix fraction dropping leading zeros

gedcom7/cast.py

@@ -79,7 +79,8 @@ def _cast_time(value: str) -> types.Time:
         hour=int(match.group("hour")),
         minute=int(match.group("minute")),
         second=int(match.group("second")) if match.group("second") else None,
-        fraction=int(match.group("fraction")) if match.group("fraction") else None,
+        # kept as a string: see the note on Time.fraction
+        fraction=match.group("fraction"),
     )
 
 

gedcom7/types.py

@@ -83,7 +83,11 @@ class Time:
     hour: int
     minute: int
     second: int | None = None
-    fraction: int | None = None
+    # The digits after the decimal point, kept verbatim. Leading zeros are part
+    # of the value: ".05" and ".5" are different instants. Trailing zeros are
+    # not, but they belong to the payload, so keeping the digits as written
+    # preserves those too.
+    fraction: str | None = None
     tz: Literal["Z"] | None = None
 
 

test/test_cast.py

@@ -88,7 +88,7 @@ def test_cast_time() -> None:
         hour=13,
         minute=15,
         second=12,
-        fraction=246,
+        fraction="246",
         tz=None,
     )
     assert cast._cast_time("13:15Z") == types.Time(
@@ -102,13 +102,26 @@ def test_cast_time() -> None:
         hour=13,
         minute=15,
         second=12,
-        fraction=246,
+        fraction="246",
         tz="Z",
     )
     with pytest.raises(ValueError):
         cast._cast_time("13:15A")  # Invalid timezone, should be Z
 
 
+def test_cast_time_preserves_fraction_width() -> None:
+    """The fraction is kept verbatim, digits as written.
+
+    Leading zeros are part of the value, so ".05" and ".5" are different
+    instants. Trailing zeros do not change the value but do belong to the
+    payload, so they are preserved as well.
+    """
+    assert cast._cast_time("13:15:12.05").fraction == "05"
+    assert cast._cast_time("13:15:12.5").fraction == "5"
+    assert cast._cast_time("13:15:12.500").fraction == "500"
+    assert cast._cast_time("13:15:12.05") != cast._cast_time("13:15:12.5")
+
+
 def test_cast_age() -> None:
     # Testing basic combinations
     assert cast._cast_age("3y") == types.Age(

test/test_util.py

@@ -126,20 +126,29 @@ def test_time_with_seconds() -> None:
 
 def test_time_with_fraction() -> None:
     """Test time conversion with fractional seconds."""
-    gedcom_time = types.Time(hour=14, minute=30, second=45, fraction=123456)
+    gedcom_time = types.Time(hour=14, minute=30, second=45, fraction="123456")
     python_time = util.time_to_python_time(gedcom_time)
 
     assert python_time.second == 45
     assert python_time.microsecond == 123456
 
     # Test with different fraction lengths
-    gedcom_time = types.Time(hour=14, minute=30, second=45, fraction=5)
+    gedcom_time = types.Time(hour=14, minute=30, second=45, fraction="5")
     python_time = util.time_to_python_time(gedcom_time)
 
     assert python_time.second == 45
     assert python_time.microsecond == 500000
 
 
+def test_time_fraction_leading_zero_is_significant() -> None:
+    """A leading zero scales the fraction: ".05" is 50 ms, not 500 ms."""
+    gedcom_time = types.Time(hour=14, minute=30, second=45, fraction="05")
+    assert util.time_to_python_time(gedcom_time).microsecond == 50000
+
+    gedcom_time = types.Time(hour=14, minute=30, second=45, fraction="5")
+    assert util.time_to_python_time(gedcom_time).microsecond == 500000
+
+
 def test_time_without_fraction_or_seconds() -> None:
     """Test time conversion without fraction or seconds."""
     gedcom_time = types.Time(hour=14, minute=30, second=None, fraction=None)
@@ -168,7 +177,7 @@ def test_date_only() -> None:
 def test_date_and_time() -> None:
     """Test conversion with both date and time."""
     gedcom_date = types.DateExact(day=15, month="JAN", year=2023)
-    gedcom_time = types.Time(hour=14, minute=30, second=45, fraction=123)
+    gedcom_time = types.Time(hour=14, minute=30, second=45, fraction="123")
 
     python_datetime = util.date_exact_and_time_to_python_datetime(
         gedcom_date, gedcom_time
@@ -197,7 +206,7 @@ def test_integration_with_other_functions() -> None:
         )
 
         gedcom_date = types.DateExact(day=15, month="JAN", year=2023)
-        gedcom_time = types.Time(hour=14, minute=30, second=45, fraction=123)
+        gedcom_time = types.Time(hour=14, minute=30, second=45, fraction="123")
 
         util.date_exact_and_time_to_python_datetime(gedcom_date, gedcom_time)