code: def test_dump_layer(path_gpx, layer):
      runner = CliRunner()
      result = runner.invoke(
          main_group, ["dump", path_gpx, "--layer", layer]
      )
      assert result.exit_code == 0
      assert '"FeatureCollection"' in result.output
  
file_path: Fiona/tests/test_fio_dump.py
imports: import json
  from click.testing import CliRunner
  import pytest
  import fiona
  from fiona.fio.main import main_group
label_desc: Use image node_id 2 for calling a global function with example usage: test_dump_layer(path_gpx, layer) without return types