class_docstr: Test update of dataset encodings.
docstr: Create fake data for testing.
docstr_tok: ["Create","fake","data","for","testing","."]
code: def fake_ds(self):
      """Create fake data for testing."""
      ds = xr.Dataset(
          {
              "foo": (("y", "x"), [[1, 2], [3, 4]]),
              "bar": (("y", "x"), [[3, 4], [5, 6]]),
          },
          coords={
              "y": [1, 2],
              "x": [3, 4],
              "lon": (("y", "x"), [[7, 8], [9, 10]]),
          },
      )
      return ds
  
file_path: satpy/satpy/tests/cf_tests/test_encoding.py
imports: import datetime
  import pytest
  import xarray
label_desc: Use image node_id 1 for calling the TestUpdateEncoding obj's underlying member method code with example usage: obj.fake_ds() and returns: ds