Add test for objects following minimal Array protocol

Author: FrancescAlted

src/blosc2/lazyexpr.py

@@ -3137,6 +3137,10 @@ def _new_expr(cls, expression, operands, guess, out=None, where=None, ne_args=No
             _operands = operands | local_vars
             _globals = get_expr_globals(expression)
             _globals |= dtype_symbols
+            # Check that operands are proper Operands, LazyArray or scalars; if not, convert to NDArray objects
+            for op, val in _operands.items():
+                if not (isinstance(val, (blosc2.Operand, blosc2.LazyArray, np.ndarray)) or np.isscalar(val)):
+                    _operands[op] = blosc2.asarray(val)
             new_expr = eval(_expression, _globals, _operands)
             _dtype = new_expr.dtype
             _shape = new_expr.shape

src/blosc2/ndarray.py

@@ -60,11 +60,6 @@ def shape(self) -> tuple[int, ...]:
         """The shape of the array."""
         ...
 
-    @property
-    def ndim(self) -> int:
-        """The number of dimensions of the array."""
-        ...
-
     def __len__(self) -> int:
         """The length of the array."""
         ...

tests/ndarray/test_lazyexpr.py

@@ -1555,3 +1555,30 @@ def test_complex_lazy_expression_multiplication():
 
     # Also test getitem access
     np.testing.assert_allclose(result_expr[:], -expected, rtol=1e-14, atol=1e-14)
+
+
+# Test checking that objects following the blosc2.Array protocol can be operated with
+def test_minimal_protocol():
+    class NewObj:
+        def __init__(self, a):
+            self.a = a
+
+        @property
+        def shape(self):
+            return self.a.shape
+
+        @property
+        def dtype(self):
+            return self.a.dtype
+
+        def __getitem__(self, key):
+            return self.a[key]
+
+        def __len__(self):
+            return len(self.a)
+
+    a = np.arange(100, dtype=np.int64).reshape(10, 10)
+    b = NewObj(a)
+    lb = blosc2.lazyexpr("b + 1")
+
+    np.testing.assert_array_equal(lb[:], a + 1)