userDefaults: Unimplemented error in case with provided dependency value

[arietis]

userDefaults: Unimplemented error in case with provided dependency value

[tgrapperon]

Hey @arietis! This is weird indeed. My guess is that there is an escaping closure somewhere (in snapshot testing or in your own code) and the dependencies are reset. You can find more information about this phenomenon in the documentation. In your case, withEscapedDependencies could help, but I'm not sure how to pass the escaped dependencies up to where it is used. Could you post a little more about View's internals? Are you using a StateObject?

[arietis]

Thanks! I have extracted the snapshotting code out of the closure and it seems to work without failures so far. Will see if it will randomly fail again or not.

[tgrapperon]

@JacksonUtsch, if you use the trailing closure to set your dependencies, it works:

let store = TestStore(
  initialState: ExampleFeature.State(),
  reducer: ExampleFeature()
) {
  $0.userDefaults = .ephemeral()
}

This is because this dependency fails as soon as you touch its test value, even if you don't call any endpoint. I did it like that because I was lazy and I didn't want to reimplement a complete failing one! I'll try to improve the situation soon.

[tgrapperon]

The trailing closure wraps everything internally in a withDependencies. This is the reducer modifier that is triggering the failure, but the value is already implemented when using the closure, so everything is fine then.
But this is rather a limitation of this specific dependency than a problem with the modifier.

[tgrapperon]

Great! I'll close the issue then. Feel free to reopen it if the problem is back!

[arietis]

The root problem was similar to this one, I just need to prevent the app from loading in tests. pointfreeco/swift-dependencies#37

[tgrapperon]

Ah indeed, I missed this possibility! This behavior is extremely annoying. Maybe there are ways to improve its diagnostic because you're not the first, and definitely not the last to trip on it.
Thanks for the follow-up!

[JacksonUtsch]

Hmm, I'm getting this same error even with the use of if !_XCTIsTesting {. I'll look to reproduce this in an isolated project.

---

It looks like the error occurs when I override the dependency in testing. I was able to reproduce this in a separate project.

import ComposableArchitecture
import XCTest
@testable import ExampleFeature

final class ExampleFeatureTests: XCTestCase {
  @MainActor
  func testExample() async {
    let store = TestStore(
      initialState: ExampleFeature.State(),
      reducer: ExampleFeature()
        .dependency(\.userDefaults, .init(suitename: "test")!)
    )

    await store.send(.test)
  }
}

[tgrapperon]

Hey @JacksonUtsch! Make sure that you're not linking your test target with Dependencies. See testing section's last paragraph in the doc (on mobile right now)

[JacksonUtsch]

It doesn't look like I have static linking. Here is a demo of the issue. 🤔

[JacksonUtsch]

Interesting.. I'm not sure how that is achieved when the dependency is overwritten. I'm guessing dependencies are iterated through internally in the TestStore or in Dependencies? And so the logic in result is different where you override.. 🤷