The test_extract_zarr_variable_encoding does not need to use the regi…

…on parameter

xarray/tests/test_backends.py

@@ -5496,26 +5496,24 @@ def test_encode_zarr_attr_value() -> None:
 
 @requires_zarr
 def test_extract_zarr_variable_encoding() -> None:
-    # The region is not useful in these cases, but I still think that it must be mandatory
-    # because the validation of the chunks is in the same function
     var = xr.Variable("x", [1, 2])
-    actual = backends.zarr.extract_zarr_variable_encoding(var, region=tuple())
+    actual = backends.zarr.extract_zarr_variable_encoding(var)
     assert "chunks" in actual
     assert actual["chunks"] is None
 
     var = xr.Variable("x", [1, 2], encoding={"chunks": (1,)})
-    actual = backends.zarr.extract_zarr_variable_encoding(var, region=tuple())
+    actual = backends.zarr.extract_zarr_variable_encoding(var)
     assert actual["chunks"] == (1,)
 
     # does not raise on invalid
     var = xr.Variable("x", [1, 2], encoding={"foo": (1,)})
-    actual = backends.zarr.extract_zarr_variable_encoding(var, region=tuple())
+    actual = backends.zarr.extract_zarr_variable_encoding(var)
 
     # raises on invalid
     var = xr.Variable("x", [1, 2], encoding={"foo": (1,)})
     with pytest.raises(ValueError, match=r"unexpected encoding parameters"):
         actual = backends.zarr.extract_zarr_variable_encoding(
-            var, raise_on_invalid=True, region=tuple()
+            var, raise_on_invalid=True
         )