cleaning up new test

xarray/tests/conftest.py

@@ -139,6 +139,26 @@ def d(request, backend, type) -> DataArray | Dataset:
         raise ValueError
 
 
+@pytest.fixture
+def byte_attrs_dataset():
+    """For testing issue #9407"""
+    null_byte = b"\x00"
+    other_bytes = bytes(range(1, 256))
+    ds = Dataset({"x": 1}, coords={"x_coord": [1]})
+    ds["x"].attrs["null_byte"] = null_byte
+    ds["x"].attrs["other_bytes"] = other_bytes
+
+    expected = ds.copy()
+    expected["x"].attrs["null_byte"] = ""
+    expected["x"].attrs["other_bytes"] = other_bytes.decode(errors="replace")
+
+    return {
+        "input": ds,
+        "expected": expected,
+        "h5netcdf_error": r"Invalid value provided for attribute .*: .*\. Null characters .*",
+    }
+
+
 @pytest.fixture(scope="module")
 def create_test_datatree():
     """

xarray/tests/test_backends.py

@@ -1404,23 +1404,12 @@ def test_refresh_from_disk(self) -> None:
                     a.close()
                     b.close()
 
-    def test_byte_attrs(self) -> None:
-        with create_tmp_file() as tmp_file:
-            try:
-                null_byte = b"\x00"
-                other_bytes = bytes(range(1, 256))
-                ds = Dataset({"x": 1}, coords={"x_coord": [1]})
-                ds["x"].attrs["null_byte"] = null_byte
-                ds["x"].attrs["other_bytes"] = other_bytes
-                self.save(ds, tmp_file)
-            except ValueError:
-                assert self.engine == "h5netcdf"
-            else:
-                with self.open(tmp_file) as ds_out:
-                    assert ds_out["x"].attrs["null_byte"] == ""
-                    assert ds_out["x"].attrs["other_bytes"] == other_bytes.decode(
-                        errors="replace"
-                    )
+    def test_byte_attrs(self, byte_attrs_dataset: dict[str, Any]) -> None:
+        # test for issue #9407
+        input = byte_attrs_dataset["input"]
+        expected = byte_attrs_dataset["expected"]
+        with self.roundtrip(input) as actual:
+            assert_identical(actual, expected)
 
 
 _counter = itertools.count()
@@ -3879,6 +3868,10 @@ def test_decode_utf8_warning(self) -> None:
                 assert ds.title == title
                 assert "attribute 'title' of h5netcdf object '/'" in str(w[0].message)
 
+    def test_byte_attrs(self, byte_attrs_dataset: dict[str, Any]) -> None:
+        with pytest.raises(ValueError, match=byte_attrs_dataset["h5netcdf_error"]):
+            super().test_byte_attrs(byte_attrs_dataset)
+
 
 @requires_h5netcdf
 @requires_netCDF4