XCTestCase with swift 6

[mdetko]

When I enable swift 6 for tests, I get errors when trying to register mocks:

extension Container {
    var testClass: Factory<TestClass> { self { TestClass() } }
}

final class TestClass {
    var value = ""
}

final class TestCase: XCTestCase {
    private let testClass = TestClass()
    
    override func setUp() {
        super.setUp()
        Container.shared.testClass.register { self.testClass }
    }
    
    func test_value() {
    }
}

I know that I could simply initialise TestClass inside closure Container.shared.testClass.register { TestClass() }, but I have a lot of cases when I keep an instance of mock and modify some properties inside test methods.

Two solutions that I could apply to fix it are:

1. Make TestClass Sendable and assign the instance to let variable before register

override func setUp() {
    super.setUp()
    let testClass = testClass
    Container.shared.testClass.register { testClass }
}

2. Make TestCase @unchecked Sendable

Do you have some recommendations which solution I should choose?