Add test and whatsnew entry

SciTools · Feb 23, 2024 · 9a8b8d9 · 9a8b8d9
1 parent bb2ec46
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diff --git a/docs/src/whatsnew/latest.rst b/docs/src/whatsnew/latest.rst
@@ -48,7 +48,8 @@ This document explains the changes made to Iris for this release
 🚀 Performance Enhancements
 ===========================
 
-#. N/A
+#. `@bouweandela`_ made :func:`iris.util.rolling_window` work with lazy arrays.
+   (:pull:`5775`)
 
 
 🔥 Deprecations

diff --git a/lib/iris/tests/unit/util/test_rolling_window.py b/lib/iris/tests/unit/util/test_rolling_window.py
@@ -8,6 +8,7 @@
 # importing anything else
 import iris.tests as tests  # isort:skip
 
+import dask.array as da
 import numpy as np
 import numpy.ma as ma
 
@@ -35,6 +36,12 @@ def test_2d(self):
         result = rolling_window(a, window=3, axis=1)
         self.assertArrayEqual(result, expected_result)
 
+    def test_3d_lazy(self):
+        a = da.arange(2 * 3 * 4).reshape((2, 3, 4))
+        expected_result = np.arange(2 * 3 * 4).reshape((1, 2, 3, 4))
+        result = rolling_window(a, window=2, axis=0).compute()
+        self.assertArrayEqual(result, expected_result)
+
     def test_1d_masked(self):
         # 1-d masked array input
         a = ma.array([0, 1, 2, 3, 4], mask=[0, 0, 1, 0, 0], dtype=np.int32)