TST: GH35131 Add failing test of numpy-like array handling

Author: znicholls

pandas/tests/dtypes/test_inference.py

@@ -59,6 +59,24 @@ def coerce(request):
     return request.param
 
 
+class DuckArray:
+    """
+    A class which wraps around numpy (e.g. Pint's Quantity) but is not actually a numpy array
+    """
+    def __init__(self, values):
+        self.values = values
+
+    def __iter__(self):
+        it_here = iter(self.values)
+
+        for element in it_here:
+            yield element
+
+    @property
+    def ndim(self):
+        return self.values.ndim
+
+
 # collect all objects to be tested for list-like-ness; use tuples of objects,
 # whether they are list-like or not (special casing for sets), and their ID
 ll_params = [
@@ -93,6 +111,15 @@ def coerce(request):
     (np.ndarray((2,) * 4), True, "ndarray-4d"),
     (np.array([[[[]]]]), True, "ndarray-4d-empty"),
     (np.array(2), False, "ndarray-0d"),
+    (DuckArray(np.ndarray((2,) * 1)), True, "duck-ndarray-1d"),
+    (DuckArray(np.array([])), True, "duck-ndarray-1d-empty"),
+    (DuckArray(np.ndarray((2,) * 2)), True, "duck-ndarray-2d"),
+    (DuckArray(np.array([[]])), True, "duck-ndarray-2d-empty"),
+    (DuckArray(np.ndarray((2,) * 3)), True, "duck-ndarray-3d"),
+    (DuckArray(np.array([[[]]])), True, "duck-ndarray-3d-empty"),
+    (DuckArray(np.ndarray((2,) * 4)), True, "duck-ndarray-4d"),
+    (DuckArray(np.array([[[[]]]])), True, "duck-ndarray-4d-empty"),
+    (DuckArray(np.array(2)), False, "duck-ndarray-0d"),
     (1, False, "int"),
     (b"123", False, "bytes"),
     (b"", False, "bytes-empty"),