def METHOD_NAME(self):
    dataset = new_cube(variables=dict(a=9, b=0.2))
    cube = dataset.xcube.cube
    self.assertIsInstance(cube, xr.Dataset)
    self.assertEqual(set(dataset.data_vars), set(cube.data_vars))
    gm = dataset.xcube.gm
    self.assertIsInstance(gm, GridMapping)