Introducing testability

[azure]

Introducing testability

[TsuyoshiUshio]

Hi @j82w ,

From my priority point of view,

1. CosmosContainer
2. CosmosDatabase
3. CosmosClient

For example, I tried to Mock the CreateContainerIfNotExistsAsync, we need this effort. However, it doesn't work because of the error. If we have an interface on it. Things might be much easier.

            var cosmosDatabaseMock = new Mock<CosmosDatabase>();
            var cosmosContainersMock = new Mock<CosmosContainers>();

            var containerResponseMock = new Mock<CosmosContainerResponse>();
            var containerMock = new Mock<CosmosContainer>();
            var container = containerMock.Object;
            containerResponseMock.Setup(p => p.Container).Returns(container);

            cosmosContainersMock.Setup(p => p.CreateContainerIfNotExistsAsync("Todo", "/UserName", null, null, default(CancellationToken)))
                .ReturnsAsync(containerResponseMock.Object);

            cosmosDatabaseMock.Setup(p => p.Containers).Returns(cosmosContainersMock.Object);
            var repository = new GenericRepository<Todo>(cosmosDatabaseMock.Object);
            Assert.Equal(container, repository.container);
            cosmosContainersMock.Verify(p => p.CreateContainerIfNotExistsAsync("Todo", "/UserName", null, null, default(CancellationToken)));

[j82w]

Hi Tsuyoshi,

Can you please provide a list of objects that can not be mocked?

[TsuyoshiUshio]

I also try to Mock the method, like this.

                this._containerResponseMock = new Mock<CosmosContainerResponse>();
               

                var expectedCosmosItemResponseMock = new Mock<CosmosItemResponse<Todo>>();
                expectedCosmosItemResponseMock.Setup(p => p.Resource).Returns(ExpectedTodo);
                expectedCosmosItemResponseMock.Setup(p => p.StatusCode).Returns(HttpStatusCode.OK);

                this._containerResponseMock.Setup(p =>
                        p.Container.Items.CreateItemAsync<Todo>(ExpectedPartitionKey, InputTodo, null, default(CancellationToken)))
                    .Returns(Task.FromResult(expectedCosmosItemResponseMock.Object));

it causes

Castle.DynamicProxy.InvalidProxyConstructorArgumentsException : Can not instantiate proxy of class: Microsoft.Azure.Cosmos.CosmosContainer.
Could not find a parameterless constructor.

Seems lack of default constructor.

I'm a new to this API, so I might misunderstand the implementation. I'm ok if I can write unit testing. (I usually use TDD method). If my implementation is not proper, please let me know how can I write the unit testing using Moq.

[j82w]

We want this to be unit testable. I will create task to add the interface. We are still working on planning so I don't currently have a time frame, but it will be done before the SDK goes GA.

[TsuyoshiUshio]

Awesome! I appreciate you. I'm trying to understand the new API and how to write unit testing for it.
I'll write a blog what I learned and current workaround for unit testing.

[j82w]

Thanks for the feedback. If you find any other blockers or have any ideas on how to make it easier to unit test please let us know.

[darthmolen]

This. Right Here. I also opened #53 with a similar problem (as you're asking for feedback but they're separate from what he's asking)

[j82w]

@TsuyoshiUshio and @darthmolen please take a look at the PR

[TsuyoshiUshio]

@J82 awesome!

[j82w]

#90