Address review comments by @mtsokol.

Author: hameerabbasi

sparse/mlir_backend/_ops.py

@@ -181,6 +181,9 @@ def add(x1: Array, x2: Array, /) -> Array:
 
 
 def asformat(x: Array, /, format: StorageFormat) -> Array:
+    if x.format == format:
+        return x
+
     out_tensor_type = format._get_mlir_type(shape=x.shape)
     ret_storage = format._get_ctypes_type(owns_memory=True)()
 

sparse/mlir_backend/tests/test_simple.py

@@ -416,9 +416,12 @@ def test_reshape_dense(dtype):
         np.testing.assert_equal(actual_np, expected)
 
 
-@pytest.mark.skip(reason="Segfault")
-@pytest.mark.parametrize("src_fmt", ["csr", "csc"])
-@pytest.mark.parametrize("dst_fmt", ["csr", "csc"])
+@pytest.mark.parametrize(
+    "src_fmt", ["csr", "csc", pytest.param("coo", marks=pytest.mark.skip(reason="TODO: Report MLIR issue"))]
+)
+@pytest.mark.parametrize(
+    "dst_fmt", ["csr", "csc", pytest.param("coo", marks=pytest.mark.skip(reason="TODO: Report MLIR issue"))]
+)
 def test_asformat(rng, src_fmt, dst_fmt):
     SHAPE = (100, 50)
     DENSITY = 0.5