text: from unittest import TestCase, skip
  from expects import *
  
  from slender import Dictionary 
  
  class TestInvert(TestCase):
      
      def test_invert_if_dictionary_is_empty(self):
          d1 = Dictionary[str, int]({})
          expect(d1.invert()).to(be_empty)
   
      def test_invert_if_dictionary_contains_different_values(self):
          d1 = Dictionary[str, int]({'a': 1, 'b': 2})
          expect(d1.invert()).to(equal(Dictionary[str, int]({1: 'a', 2: 'b'})))
    
      def test_invert_if_dictionary_contains_same_values(self):
          d1 = Dictionary[str, int]({'a': 1, 'b': 1})
          expect(d1.invert()).to(equal(Dictionary[str, int]({1: 'b'})))
  
  
  