fix {hot|cold}_spell_max_length (#1777)

### What kind of change does this PR introduce?

* Fixes a bug. `{hot|cold}_spell_max_length` were not properly using
`window` to only count spells with at least `window` time steps, now
they do.

### Does this PR introduce a breaking change?
* Yes, output of functions will sometimes change (and work as expected)

CHANGES.rst

@@ -4,7 +4,7 @@ Changelog
 
 v0.50.0 (unreleased)
 --------------------
-Contributors to this version: Trevor James Smith (:user:`Zeitsperre`).
+Contributors to this version: Trevor James Smith (:user:`Zeitsperre`), Éric Dupuis (:user:`coxipi`).
 
 Breaking changes
 ^^^^^^^^^^^^^^^^
@@ -18,6 +18,10 @@ Internal changes
 * Fixed some previously uncaught errors raised from recent versions of `pylint` and `codespell`. (:pull:`1772`).
 * Set the `doctest` examples to all use `h5netcdf` with worker-separated caches to load datasets. (:pull:`1772`).
 
+Bug fixes
+^^^^^^^^^
+* ``xclim.indices.{cold|hot}_spell_total_length`` now properly uses the argument `window` to only count spells with at least `window` time steps. (:issue:`1765`, :pull:`1777`).
+
 v0.49.0 (2024-05-02)
 --------------------
 Contributors to this version: Trevor James Smith (:user:`Zeitsperre`), Pascal Bourgault (:user:`aulemahal`), Juliette Lavoie (:user:`juliettelavoie`), David Huard (:user:`huard`), Gabriel Rondeau-Genesse (:user:`RondeauG`), Javier Diez-Sierra (:user:`JavierDiezSierra`), Sarah Gammon (:user:`SarahG-579462`), Éric Dupuis (:user:`coxipi`).

tests/test_indices.py

@@ -1421,7 +1421,7 @@ class TestHotSpellTotalLength:
             ("29 C", 3, ">", 8),  # Two HS
             ("29 C", 3, ">=", 9),  # One long HS, minus a day
             ("40 C", 3, ">", 0),  # No HS
-            ("30 C", 5, ">", 8),  # Windowed
+            ("30 C", 5, ">", 5),  # Windowed
         ],
     )
     def test_1d(self, tasmax_series, thresh, window, op, expected):

xclim/indices/_threshold.py

@@ -336,14 +336,13 @@ def cold_spell_total_length(
     thresh = convert_units_to(thresh, tas)
 
     cond = compare(tas, op, thresh, constrain=("<", "<="))
-    max_l = rl.resample_and_rl(
+    out = rl.resample_and_rl(
         cond,
         resample_before_rl,
         rl.windowed_run_count,
-        window=1,
+        window=window,
         freq=freq,
     )
-    out = max_l.where(max_l >= window, 0)
     return to_agg_units(out, tas, "count")
 
 
@@ -2112,14 +2111,13 @@ def hot_spell_total_length(
     thresh = convert_units_to(thresh, tasmax)
 
     cond = compare(tasmax, op, thresh, constrain=(">", ">="))
-    max_l = rl.resample_and_rl(
+    out = rl.resample_and_rl(
         cond,
         resample_before_rl,
         rl.windowed_run_count,
-        window=1,
+        window=window,
         freq=freq,
     )
-    out = max_l.where(max_l >= window, 0)
     return to_agg_units(out, tasmax, "count")