text: import unittest
  
  from dpsniper.classifiers.feature_transformer import *
  from tests.my_test_case import MyTestCase
  
  
  class TestFeatureTransformers(MyTestCase):
  
      def test_1_flag_transformer(self):
          trans = FlagsFeatureTransformer([-1])
          x = np.array([[-3, -1, 4], [-3, 2, -3]])
          y = trans.transform(x)
          np.testing.assert_array_equal(y, np.array([[-3, 0, 4, 0, 1, 0],
                                                     [-3, 2, -3, 0, 0, 0]]))
  
      def test_2_flags_transformer(self):
          trans = FlagsFeatureTransformer([-1, -3])
          x = np.array([[-3, -1, 4], [-3, 2, -3]])
          y = trans.transform(x)
          np.testing.assert_array_equal(y, np.array([[0, 0, 4, 0, 1, 0, 1, 0, 0],
                                                     [0, 2, 0, 0, 0, 0, 1, 0, 1]]))
  