public async Task GetAvaliableDistrictsAsync_ShouldReturnOnlyWolaAndBemowo()
        {
            _notificationSystem = new NotificationSystem(string.Empty);
            var expectedResult = new List <District>
            {
                new District("Bemowo"),
                new District("Wola")
            };


            var results = await _notificationSystem.GetAvaliableDistrictsAsync();

            results.Should().NotBeNull();
            results.Should().BeEquivalentTo(expectedResult);
        }