Can not set a default Local for TestValue

[lbulendev]

I am using the locale dependency that is provided by the library [@dependency(.locale) var currentLocale]. I would like to find out how to set a default Locale in all of my tests. Currently, I am specifying the locale dependency for each test that needs it as follows:

withDependencies: {
            $0.locale = Locale(identifier: "en_US")
}

But, I would prefer to set a TestValue such as (below), like I do for my other dependencies. Since testValue and previewValue are not provided by the library. I am doing it as below:

extension Locale: TestDependencyKey {
    public static var testValue = Locale(identifier: "en_US")
    public static var previewValue = Locale(identifier: "en_US")
}

However, this doesn't work, because I get this error when I run my tests:
Locale.swift:36: failed - @dependency(.locale) has no test implementation, but was accessed from a test context:

It's not clear to me how to set a default testValue instead I have to set a locale value in each of my tests.

Any help/tips would be greatly appreciated. Thanks.

[mbrandonw]

Currently, I am specifying the locale dependency for each test that needs it as follows:

That is the way to do this. If you are using XCTest you can do this for an entire test class using invokeTest:

class MyTests: XCTest {
  override func invokeTest() {
    withDependencies {
      $0.locale = Locale(identifier: "en_US")
    } operation: {
      super.invokeTest()
    }
  }
  // ...
}

Or if you are using Swift Testing, you can use the DependenciesTestSupport library that vends a .dependency test trait:

@Suite(.dependency(\.locale, Locale(identifier: "en_US")))
struct MyTests {
  // ...
}

Or, alternatively, you can define your own dependency for locales that sets the testValue and previewValue to whatever you want.