text: import unittest
  from credentials import Credentials
  
  class TestUser(unittest.TestCase):
      '''
      Test class that defines the test cases for user class
      behaviours
      '''
      def setUp(self):
          '''
          Setup method to run before each test cases
          '''
          self.new_credential = Credentials("snapchat","qqqqqq")
      def test_init(self):
          '''
          test_init checks if the object is initialised properly
          '''
          self.assertEqual(self.new_credential.account_name,"snapchat")
          self.assertEqual(self.new_credential.password,"qqqqqq")
      def tearDown(self):
          '''
          TearDown method that does clean up after each test case has run.
          '''
          Credentials.credentials_list = []
  
      def test_save_credential(self):
          '''
          test_save_credential tests if a new credential has been added to the credentials_list 
          '''
          self.new_credential.save_credentials()
          self.assertEqual(len(Credentials.credentials_list),1)
      
      def test_display_credentials(self):
          '''
          test to display the credentials
          '''
          self.assertEqual(Credentials.display_credentials(),Credentials.credentials_list)
      
      def test_delete_credential(self):
          '''
          test_delete_credential to see if we can remove a 
          credential from credentials list
          '''
          self.new_credential.save_credentials()
          test_credential = Credentials("snapchat","qqqqqq")
          test_credential.save_credentials()
          self.new_credential.delete_credentials("snapchat","qqqqqq")
          self.assertEqual(len(Credentials.credentials_list),2)
  
  if __name__ == '__main__':
      unittest.main()