disable linear_ramp test and add pad to whats-new.rst and api.rst

Author: mark-boer

doc/api.rst

@@ -220,6 +220,7 @@ Reshaping and reorganizing
    Dataset.to_stacked_array
    Dataset.shift
    Dataset.roll
+   Dataset.pad
    Dataset.sortby
    Dataset.broadcast_like
 
@@ -399,6 +400,7 @@ Reshaping and reorganizing
    DataArray.to_unstacked_dataset
    DataArray.shift
    DataArray.roll
+   DataArray.pad
    DataArray.sortby
    DataArray.broadcast_like
 

doc/whats-new.rst

@@ -25,6 +25,8 @@ Breaking changes
 
 New Features
 ~~~~~~~~~~~~
+- Implement :py:meth:`DataArray.pad` and :py:meth:`Dataset.pad`. (:issue:`2605`).
+  By `Mark Boer <https://github.com/mark-boer>`_.
 - Implement :py:func:`median` and :py:func:`nanmedian` for dask arrays. This works by rechunking
   to a single chunk along all reduction axes. (:issue:`2999`).
   By `Deepak Cherian <https://github.com/dcherian>`_.

xarray/tests/test_variable.py

@@ -792,7 +792,7 @@ def test_getitem_error(self):
             pytest.param("median", marks=pytest.mark.xfail),
             pytest.param("reflect", marks=pytest.mark.xfail),
             "edge",
-            "linear_ramp",
+            pytest.param("linear_ramp", marks=pytest.mark.xfail),
             "maximum",
             "minimum",
             "symmetric",