old_contents: from click.testing import CliRunner
  
  from regparser.commands.derive_depths import derive_depths
  
  
  def test_produces_usage_message_with_no_arg():
      result = CliRunner().invoke(derive_depths)
      assert result.exit_code == 2
      assert 'Usage' in result.output
  
  
  def test_returns_simple_result_for_a_simple_outline():
      result = CliRunner().invoke(derive_depths, '(a),(b),(c)')
      assert result.exit_code == 0
      assert result.output == "[0, 0, 0]\n"
  
new_contents: from click.testing import CliRunner
  
  from regparser.commands.derive_depths import derive_depths
  
  
  def test_produces_usage_message_with_no_arg():
      result = CliRunner().invoke(derive_depths)
      assert result.exit_code == 2
      assert 'Usage' in result.output
  
  
  def test_returns_simple_result_for_a_simple_outline():
      result = CliRunner().invoke(derive_depths, ['a, b, c'])
      assert result.exit_code == 0
      assert result.output == "0, 0, 0\n"
  
subject: Test is failing properly