Fix fractional() emitting degenerate output when the fraction rounds to a whole

When limit_denominator(1000) reduces the fractional part to a whole number
(denominator == 1), fold it into the integer part instead of printing a
degenerate "N/1". For example fractional(2.9999999) returned "2 1/1"
instead of "3", fractional(0.9999999) returned "1/1" instead of "1",
and fractional(0) returned "0/1" instead of "0".

Author: semx

src/humanize/number.py

@@ -361,10 +361,12 @@ def fractional(value: NumberOrString) -> str:
     frac = Fraction(number - whole_number).limit_denominator(1000)
     numerator = frac.numerator
     denominator = frac.denominator
-    if whole_number and not numerator and denominator == 1:
-        # this means that an integer was passed in
-        # (or variants of that integer like 1.0000)
-        return f"{whole_number:.0f}"
+    if denominator == 1:
+        # The fractional part reduced to a whole number: either an integer
+        # was passed in (e.g. 1 or 1.0000, giving 0/1), or the fractional part
+        # rounded up to 1/1 (e.g. 2.9999999). Fold it into the integer part
+        # instead of emitting a degenerate "0/1" or "2 1/1".
+        return f"{whole_number + numerator:.0f}"
 
     if not whole_number:
         return f"{numerator:.0f}/{denominator:.0f}"

tests/test_number.py

@@ -187,6 +187,11 @@ def test_apnumber(test_input: int | str, expected: str) -> None:
         (-1.3, "-1 3/10"),
         (-2.5, "-2 1/2"),
         (-0.5, "-1/2"),
+        (0, "0"),
+        (0.0, "0"),
+        (2.9999999, "3"),
+        (0.9999999, "1"),
+        (-2.9999999, "-3"),
     ],
 )
 def test_fractional(test_input: float | str, expected: str) -> None: