Mocked WikiSite

[HarelM]

Hi,
I have the following code which is a gateway wrapper for my needs in my app.
https://github.com/IsraelHikingMap/Site/blob/2fe5d229322c46fbafb15f327ba74acbcbbf480d/IsraelHiking.DataAccess/WikimediaCommonGateway.cs
I'm trying to see if I can create some unit tests to this class.
So I need to replace the hard coded new WikiClient and new WikiSite and move those to a factory.
But then I'd need some interface to return from that factory in order to be able to mock it easily.
Is there an interface I can use for WikiSite?

[CXuesong]

While there is no replacement for WikiSite, and I won't suggest replacing it at the moment as there are heavy JSON serialization logic inside it, I think you could probably try replacing the WikiClient instead.

You can implement IWikiClient with your own mock-up, and now the problem would be how to implement IWikiClient.InvokeAsync<T> so it can fulfill most of the API requests needed by WikiSite.

1. You can try either to capture the network traffic or to override the WikiClient.CreateHttpRequestMessage in order to see which requests are necessary to fulfill your test path.
2. Then you can just fulfill these requests (in the form of WikiRequestMessage, which can be broken down into URL + Method + HttpContent) with your own mocked HttpResponseMessage (You will need to feed it into provided IWikiResponseMessageParser<T> responseParser).
   • You can take a look at the existing implementation WikiClient.InvokeAsync<T> for reference.
   • Don't be not afraid of the typeparam T -- you just need to leverage the responseParser and it should not give you too much trouble.

While the approach may seem a bit involved, but it should be straightforward if you are just replacing the responses on the HTTP request layer.

[HarelM]

Not sure I fully understand.
I'm using NSubstitute for my tests.
I don't think I can replace httpclient in either wikisite or wikiclient, right?
I know I can setup a wiremock kind of server, but if wikisite had an interface and/wikiclient had an interface I could easily mock these.
My other possibility, which is not a bad one, is to move this logic to a helper class that I can unit test and avoid needing to mock parts of this library.
But it's worth considering adding some interfaces to allow better mocking of this.
I've done this in this repo for example:
https://github.com/OsmSharp/io-api
Both facilitate a factory and also introduced interfaces for testing.

[CXuesong]

I don't think I can replace httpclient in either wikisite or wikiclient, right?

Correct.

if wikisite had an interface and/wikiclient had an interface I could easily mock these.

Note that IWikiClient is an interface.

While WikiSite is not mock-friendly, the ctor of WikiSite takes an IWikiClient instance instead of WikiClient, so you can try mocking IWikiClient.

And my previous comment was mentioning some of the key points that I can think of.

[HarelM]

I ended up moving the logic out of the data access layer so that I could test it without the need to mock wiki stuff.
Thanks!