Add an "all" granularity to humanize

It's more convenient to pass a simple short string than to pass a list
of 7 strings.

Resolve arrow-py#997

arrow/arrow.py

@@ -69,6 +69,7 @@
 
 _GRANULARITY = Literal[
     "auto",
+    "all",
     "second",
     "minute",
     "hour",
@@ -1130,7 +1131,8 @@ def humanize(
         :param locale: (optional) a ``str`` specifying a locale.  Defaults to 'en-us'.
         :param only_distance: (optional) returns only time difference eg: "11 seconds" without "in" or "ago" part.
         :param granularity: (optional) defines the precision of the output. Set it to strings 'second', 'minute',
-                           'hour', 'day', 'week', 'month' or 'year' or a list of any combination of these strings
+                           'hour', 'day', 'week', 'month' or 'year' or a list of any combination of these strings.
+                           Set it to 'all' to include all possible units in the granularity.
 
         Usage::
 
@@ -1228,7 +1230,7 @@ def humanize(
                     years = sign * max(delta_second // self._SECS_PER_YEAR, 2)
                     return locale.describe("years", years, only_distance=only_distance)
 
-            elif isinstance(granularity, str):
+            elif isinstance(granularity, str) and granularity != "all":
                 granularity = cast(TimeFrameLiteral, granularity)  # type: ignore[assignment]
 
                 if granularity == "second":
@@ -1282,6 +1284,10 @@ def gather_timeframes(_delta: float, _frame: TimeFrameLiteral) -> float:
                     "minute",
                     "second",
                 )
+
+                if granularity == "all":
+                    granularity = cast(List[_GRANULARITY], frames)
+
                 for frame in frames:
                     delta = gather_timeframes(delta, frame)
 

tests/test_arrow.py

@@ -2032,6 +2032,49 @@ def test_multiple_granularity(self):
             == "a minute and 2 seconds ago"
         )
 
+    def test_all_granularity(self):
+        assert (
+            self.now.humanize(granularity="all")
+            == "in 0 years 0 months 0 weeks 0 days 0 hours 0 minutes and 0 seconds"
+        )  # TODO: this should be "ago"; change this when #997 is merged
+
+        later105 = self.now.shift(seconds=10 ** 5)
+        assert (
+            self.now.humanize(later105, granularity="all")
+            == "0 years 0 months 0 weeks a day 3 hours 46 minutes and 40 seconds ago"
+        )
+        assert (
+            later105.humanize(self.now, granularity="all")
+            == "in 0 years 0 months 0 weeks a day 3 hours 46 minutes and 40 seconds"
+        )
+
+        later108 = self.now.shift(seconds=10 ** 8)
+        assert (
+            self.now.humanize(later108, granularity="all")
+            == "3 years 2 months 0 weeks a day 9 hours 46 minutes and 40 seconds ago"
+        )
+        assert (
+            later108.humanize(self.now, granularity="all")
+            == "in 3 years 2 months 0 weeks a day 9 hours 46 minutes and 40 seconds"
+        )
+        assert (
+            self.now.humanize(later108, granularity="all", only_distance=True)
+            == "3 years 2 months 0 weeks a day 9 hours 46 minutes and 40 seconds"
+        )
+
+        later_two_months = self.now.shift(months=2)
+        assert (
+            self.now.humanize(later_two_months, granularity="all")
+            == "in 0 years 2 months 0 weeks 0 days 0 hours 0 minutes and 0 seconds"
+        )  # TODO: this should be "ago"; change this when #997 is merged
+        assert (
+            later_two_months.humanize(self.now, granularity="all")
+            == "in 0 years 2 months 0 weeks 0 days 0 hours 0 minutes and 0 seconds"
+        )
+
+        with pytest.raises(ValueError):
+            self.now.humanize(later108, granularity=["all", "year"])
+
     def test_seconds(self):
 
         later = self.now.shift(seconds=10)