public async Task PutAsync_Test() { //Arrange var group = Fixture.Create <Models.Group>(); var document = new Group { Id = _id, ApplicationId = ApplicationId, Name = group.Name }; Container.ReadItemAsync <Group>(Arg.Is(_id), Arg.Any <PartitionKey>()) .Returns(CreateItemResponse(HttpStatusCode.OK, document)); //Act var result = await _sut.PutAsync(ApplicationId, _id, group).ConfigureAwait(false); //Assert result.Should().NotBeNull(); result.Should().BeOfType <OkObjectResult>(); var ok = result as OkObjectResult; ok.Should().NotBeNull(); var groupResult = ok.Value as Models.Group; groupResult.Should().NotBeNull(); await Container.Received(1) .ReadItemAsync <Group>(Arg.Is(_id), Arg.Any <PartitionKey>()) .ConfigureAwait(false); }