def test_01(self):
     self.assertEqual(Server.reading_length_of_data('asdasd'), 'error', 'error is not returned for nondigits')
 def test_05(self):
     self.assertEqual(Server.handling_data('AB5C00e15helloqwertyuiop'), 'error', 'error should be returned')
 def test_04(self):
     self.assertEqual(Server.handling_data('AB5C0005hello'), 'hello', 'message is not received successfully')
 def test_05(self):
     self.assertEqual(Server.handling_data('AB5C0015helloqwertyuiop'), 'helloqwertyuiop', 'message is not received successfully')
 def test_02(self):
     self.assertEqual(Server.reading_length_of_data('12345'), '1234', 'returned digits are wrong')