TST: add a test for ma.minimum.reduce with axis keyword

Adapted from the problem reported at
https://github.com/numpy/numpy/pull/21977#issuecomment-1186082534

1 files changed, 12 insertions, 0 deletions

diff --git a/numpy/ma/tests/test_core.py b/numpy/ma/tests/test_core.py
index 5b779edcb..c2ba6fd77 100644
--- a/numpy/ma/tests/test_core.py
+++ b/numpy/ma/tests/test_core.py
@@ -1235,6 +1235,18 @@ class TestMaskedArrayArithmetic:
         b = np.maximum.reduce(a)
         assert_equal(b, 3)
 
+    def test_minmax_reduce_axis(self):
+        # Test np.min/maximum.reduce along an axis for 2D array
+        import numpy as np
+        data = [[0, 1, 2, 3, 4, 9], [5, 5, 0, 9, 3, 3]]
+        mask = [[0, 0, 0, 0, 0, 1], [0, 0, 1, 1, 0, 0]]
+        a = array(data, mask=mask)
+
+        expected = array([0, 3], mask=False)
+        result = np.minimum.reduce(a, axis=1)
+
+        assert_array_equal(result, expected)
+
     def test_minmax_funcs_with_output(self):
         # Tests the min/max functions with explicit outputs
         mask = np.random.rand(12).round()