swift - 变量仅用于在单元测试中保持实例处于事件状态，并收到 "only written to but never read"警告

Question

在这里，我使用 Quick 对代码的一部分进行单元测试，我声明了容器变量以使其在weaklyScpoed 闭包之外保持事件状态。然后我收到警告...

describe("foo") {
    it("bar") {
        // warning: variable "container" was written to, but never read
        var container: NSFPrioritizedDelegateContainer?
        let result = weaklyScoped(NSObject()) {
            container = NSFPrioritizedDelegateContainer.init(delegates: [$0], weakRef: true)
        }

        expect(result).to(beNil())
    }
}

“weaklyScoped”函数也很简单

func weaklyScoped<T: AnyObject>(_ v: @autoclosure () -> T, action: (T) throws -> ()) rethrows -> T? {
    weak var weakValue: T?
    do { // optionally autoreleasepool
        let value = v()
        try action(value)
        weakValue = value
    }

    return weakValue
}

如何删除警告并使容器在weaklyScoped 闭包之外保持事件状态？

Answer 1

说

_ = container

这样你就可以无害地读取它的值。