new_contents: import pandas as pd
  from pandas.util.testing import assert_series_equal
  import pytest
  
  from windpowerlib.wind_turbine import read_turbine_data, WindTurbine
  
  class TestWindTurbine:
  
      def test_error_raising(self):
          self.test_turbine_data = {'hub_height': 100,
                                    'rotor_diameter': 80,
                                    'name': 'turbine_not_in_file',
                                    'fetch_curve': 'power_curve',
                                    'data_source': 'example_power_curves.csv'}
          # Raise system exit
          with pytest.raises(SystemExit):
              test_turbine = WindTurbine(**self.test_turbine_data)
  
          # Raise ValueError due to invalid parameter `fetch_curve`
          self.test_turbine_data['fetch_curve'] = 'misspelling'
          self.test_turbine_data['name'] = 'DUMMY 3'
          with pytest.raises(ValueError):
              test_turbine = WindTurbine(**self.test_turbine_data)
  
      def test_read_turbine_data(self):
          # Raise FileNotFoundError due to missing
          with pytest.raises(FileNotFoundError):
              read_turbine_data(filename='not_existent')
  
  
subject: Add tests for wind_turbine module