class_docstr: Testing the file handler.
class_docstr_tok: ["Testing","the","file","handler","."]
docstr: Set up the tests.
code: def setUp(self, xr_):
      """Set up the tests."""
      from satpy.readers.goes_imager_nc import (
          CALIB_COEFS,
          GOESNCBaseFileHandler,
      )
  
      self.coefs = CALIB_COEFS["GOES-15"]
  
      # Mock file access to return a fake dataset.
      self.time = datetime.datetime(2018, 8, 16, 16, 7)
      self.dummy3d = np.zeros((1, 2, 2))
      self.dummy2d = np.zeros((2, 2))
      self.band = 1
      self.nc = xr.Dataset(
          {
              "data": xr.DataArray(
                  self.dummy3d, dims=("time", "yc", "xc")
              ),
              "lon": xr.DataArray(data=self.dummy2d, dims=("yc", "xc")),
              "lat": xr.DataArray(data=self.dummy2d, dims=("yc", "xc")),
              "time": xr.DataArray(
                  data=np.array([self.time], dtype="datetime64[ns]"),
                  dims=("time",),
              ),
              "bands": xr.DataArray(data=np.array([self.band])),
          },
          attrs={"Satellite Sensor": "G-15"},
      )
      xr_.open_dataset.return_value = self.nc
  
      # Instantiate reader using the mocked open_dataset() method. Also, make
      # the reader believe all abstract methods have been implemented.
      self.reader = GOESNCBaseFileHandler(
          filename="dummy", filename_info={}, filetype_info={}
      )
  
imports: import datetime
  import unittest
  from unittest import mock
  import numpy
  import pytest
  import xarray
  from pyresample.geometry import AreaDefinition
  from satpy.readers.goes_imager_nc import is_vis_channel
  from satpy.tests.utils import make_dataid
label_desc: Use image node_id 1 for calling the GOESNCBaseFileHandlerTest obj's underlying member method code with example usage: obj.setUp(xr_) without return types