Question

我想在目标c中编写单元测试。为此，仅在观察对象的键值变为期望值时才需要运行测试。

Apple文档没有详细解释该实现。任何示例代码都会有很大帮助。

Answer 1

这是Swift中的一个示例实现，我希望这可以向您展示如何使用KVO期望值。

传递给期望值的处理程序将两个对象作为输入（您正在观察的对象和变化字典）。如果您对值已按预期更改感到满意，则应返回true，如果未满足期望，则应返回false。

class Person: NSObject {
    @objc dynamic var name: String

    init(name: String) {
        self.name = name
    }

    func changeName(to newName: String) {
        name = newName
    }
}

class Tests: XCTestCase {
    func testNameValueChangedWhenChangeNameCalled() {
        let person = Person(name: "Alice")
        let newName = "Bob"
        keyValueObservingExpectation(for: person, keyPath: "name", handler: { (observedObject, change) in
            // `observedObject` is of type `Any` so it needs to be cast as the correct type before proceeding
            guard let observedObject = observedObject as? Person else {
                // Don't fulfill the expectation
                return false
            }
            // Check the current name is the name we expect
            return observedObject.name == newName
        })
        person.changeName(to: newName)
        waitForExpectations(timeout: 1, handler: nil)
    }
}

您还可以直接初始化XCTKVOExpectation并使用XCTWaiter来更精细地处理结果。

let person = Person(name: "Alice")
let newName = "Bob"
let expectation = XCTKVOExpectation(keyPath: "name", object: person)
expectation.handler = { (observedObject, change) in
    guard let observedObject = observedObject as? Person else {
        return false
    }
    return observedObject.name == newName
}
person.changeName(to: newName)
let result = XCTWaiter().wait(for: [expectation], timeout: 1)
XCTAssertEqual(result, .completed)

Answer 2

以下是如何使用keyValueObservingExpectation的示例：

let testClass = MyViewController()
let expectation = keyValueObservingExpectation(for: testClass, keyPath: #keyPath(MyViewController.urlString))
wait(for: [expectation], timeout: 10)

要使用它，必须使用#keyPath（MyViewController.urlString）指定keyPath。在该代码中，正在观察urlString的值。

这是此https://www.rockhoppertech.com/blog/kvo-quick-spec-unit-tests/

的另一个示例

目标c中的XCTKVOExpectation用法示例

2 个答案: