code: def test_gdf_data():
      """Test reading raw GDF 1.x files."""
      raw = read_raw_gdf(
          gdf1_path.with_name(gdf1_path.name + ".gdf"),
          eog=None,
          misc=None,
          preload=True,
      )
      picks = pick_types(raw.info, meg=False, eeg=True, exclude="bads")
      data, _ = raw[picks]
  
      # Test Status is added as event
      EXPECTED_EVS_ONSETS = raw._raw_extras[0]["events"][1]
      EXPECTED_EVS_ID = {
          f"{evs}": i
          for i, evs in enumerate(
              [
                  32769,
                  32770,
                  33024,
                  33025,
                  33026,
                  33027,
                  33028,
                  33029,
                  33040,
                  33041,
                  33042,
                  33043,
                  33044,
                  33045,
                  33285,
                  33286,
              ],
              1,
          )
      }
      evs, evs_id = events_from_annotations(raw)
      assert_array_equal(evs[:, 0], EXPECTED_EVS_ONSETS)
      assert evs_id == EXPECTED_EVS_ID
  
      # this .npy was generated using the official biosig python package
      raw_biosig = np.load(
          gdf1_path.with_name(gdf1_path.name + "_biosig.npy")
      )
      raw_biosig = raw_biosig * 1e-6  # data are stored in microvolts
      data_biosig = raw_biosig[picks]
  
      # Assert data are almost equal
      assert_array_almost_equal(data, data_biosig, 8)
  
      # Test for events
      assert len(raw.annotations.duration == 963)
  
      # gh-5604
      assert raw.info["meas_date"] is None
  
file_path: mne-python/mne/io/edf/tests/test_gdf.py
imports: import shutil
  from datetime import datetime, timedelta, timezone
  import numpy
  import pytest
  import scipy.io
  from numpy.testing import assert_array_almost_equal, assert_array_equal, assert_equal
  from mne import events_from_annotations, find_events, pick_types
  from mne.datasets import testing
  from mne.io import read_raw_gdf
  from mne.io.tests.test_raw import _test_raw_reader
label_desc: Use image node_id 1 for calling a global function with example usage: test_gdf_data() without return types