old_contents: import numpy as np
  from scipy import stats
  from ranking import train
  
  def test_1():
      np.random.seed(0)
      X = np.random.randn(20, 5)
      w = np.random.randn(5)
      y = np.dot(X, w)
      w_ = train(X, y, 1., np.ones(20))
  
      tau, _ = stats.kendalltau(y, np.dot(X, w))
      assert np.abs(1 - tau) > 1e-3
  
new_contents: import numpy as np
  from scipy import stats
  from ranking import train
  
  def test_1():
      np.random.seed(0)
      X = np.random.randn(20, 5)
      w = np.random.randn(5)
      y = np.dot(X, w)
      w_ = train(X, y, 100, np.ones(20))
      tau, _ = stats.kendalltau(y, np.dot(X, w_))
      assert np.abs(1 - tau) > 1e-3
  
subject: Fix test