I've got an API client class which creates an `Htt...

# ktor

[bbaldino]

I've got an API client class which creates an HttpClient and I want to add a hook so I can pass a MockEngine in for unit testing, but running into a few issues:
My first thought was to have the entire client be a ctor param and default it to what I want, i.e.:

class MyClass(
    private val client: HttpClient = HttpClient(Apache) {
        install(JsonFeature) { ... }
    }
) {

but then if I pass in a mock client, MyClass won't install the JsonFeature, so next I thought about passing in the engine:

class MyClass(
    private val clientEngine: HttpClientEngine = Apache
) {

but this doesn't work because Apache isn't an HttpClientEngine, it's an HttpClientEngineFactory. And I don't want to change the ctor to take in a HttpClientEngineFactory because it has a generic type and I don't want to add a generic to the class just to support this. I'm assuming there must be something simple here I'm missing?

[bbaldino]

Hmm, well I realized if I want to be able to take in a MockEngine, then I won't be able to assume it's an ApacheConfig anyway, so I ended up just taking in HttpClientEngineFactory<*>.

[bbaldino]

I guess if I need some Apache-specific setting in the future I'll have to figure something else out.

[bbaldino]

🤦 just realized that the stubs for requests are in the MockEngine config which needs to be applied, so this won't quite work either.

[bbaldino]

I ended up taking an HttpClient in a private constructor of my wrapper and added a generic helper function which takes in engineFactory: HttpClientEngineFactory<T> and block: HttpClientConfig<T>.() -> Unit = {}

[bbaldino]

For anyone who might find this, I did finally stumble onto the better way: take in an HttpClient in the ctor, and then call .config {...} on it to add more config (which returns a new HttpClient with a combination of any original config and the newly-added config)