public async Task GetAddressesByZipCodeShouldReturnOkIfFoundInDatabase() { // Arrange var zip = "80-765"; var address = new Address() { Id = 1, Country = "Polska", City = "Sopot", Street = "Ciasna", BuildingNumber = "1", FlatNumber = "69", PostalCode = zip }; mockRepo.Setup(x => x.Address).Returns(_addressRepoMock.Object); _addressRepoMock.Setup(x => x.GetAddressByZipCode(zip)).ReturnsAsync(new[] { address }); // Act var result = await _sut.GetAddressesByZipCode(zip); // Assert Assert.IsType <OkObjectResult>(result); Assert.IsNotType <NotFoundResult>(result); }