Add a regression test to ensure Hidalgo handles duplicate rows without errors

Author: satwiksps

aeon/segmentation/tests/test_hidalgo.py

@@ -9,3 +9,33 @@ def test_partition_function():
     assert p == 8.0
     b = _binom(10, 2)
     assert b == 45.0
+
+
+def test_hidalgo_zero_distance_duplicate_rows():
+    """Test that Hidalgo handles duplicate rows without numerical errors."""
+    import numpy as np
+
+    from aeon.segmentation._hidalgo import HidalgoSegmenter
+
+    X = np.array(
+        [
+            [1.0, 2.0, 3.0],
+            [1.0, 2.0, 3.0],
+            [4.0, 5.0, 6.0],
+            [7.0, 8.0, 9.0],
+        ]
+    )
+
+    seg = HidalgoSegmenter(
+        K=2,
+        q=2,
+        n_iter=50,
+        burn_in=0.2,
+        sampling_rate=5,
+        seed=1,
+    )
+
+    out = seg.fit_predict(X, axis=0)
+    assert out is not None
+    assert isinstance(out, np.ndarray)
+    assert len(out) == len(X)