[英]Can you use async/await in swift along with a test scheduler?
We use the Pointfree Combine Schedulers , specifically theTestScheduler , extensively in our unit tests.我们在单元测试中广泛使用Pointfree Combine Scheduler ,特别是TestScheduler 。
Is there a way to use this same library, or a similar test scheduler library, with the new async/await in Swift?有没有办法在 Swift 中使用这个相同的库或类似的测试调度程序库以及新的异步/等待? Basically, can you programmatically move and advance through time in the reactive streams produced by async/await?
基本上,您能否以编程方式在 async/await 生成的反应流中随时间移动和前进?
Why might we want this?我们为什么要这个? As Pointfree describes:
正如 Pointfree 所描述的:
This scheduler is useful for testing how the flow of time effects publishers that use asynchronous operators, such as debounce, throttle, delay, timeout, receive(on:), subscribe(on:) and more
此调度程序可用于测试时间流如何影响使用异步运算符的发布者,例如 debounce、throttle、delay、timeout、receive(on:)、subscribe(on:) 等
It appears that Swift has recently introduced Swift Async Algorithms that include support for many of these operators. Swift 似乎最近引入了Swift 异步算法,其中包括对其中许多运算符的支持。 How does the community test these operators?
社区如何测试这些运营商?
A similar question was asked a few months back, but the solution seems to propose waiting for the actual amount of time.几个月前有人问过类似的问题,但解决方案似乎建议等待实际时间。 Obviously if you have a 10 or 30 second timeout, one does not want to literally wait 10 or 30 seconds in their test.
显然,如果您有 10 或 30 秒的超时,那么人们不想在他们的测试中真正等待 10 或 30 秒。
If I understand your question correctly, you are looking into a way to test async/await code.如果我正确理解你的问题,你正在寻找一种方法来测试异步/等待代码。 If that's correct, let's image you have the following
DataDownloader
which will execute an async function to download something:如果这是正确的,让我们假设您有以下
DataDownloader
,它将执行一个异步函数来下载一些东西:
struct DataDownloader {
func downloadData() async throws -> Data {
...
}
}
In order to call that function we will need to use await
, which would basically mark that the calls need to happen in a concurrency supported context.为了调用该函数,我们需要使用
await
,这基本上标志着调用需要在并发支持的上下文中发生。 Fortunately Apple's XCTest
has been upgraded to support that.幸运的是,Apple 的
XCTest
已经升级以支持它。 We don't need to wrap it in a Task
.我们不需要将它包装在
Task
中。 So the trick is that in your test you can mark any function as async
and you will be use the await
.所以诀窍是在你的测试中你可以将任何函数标记为
async
并且你将使用await
。 A simple example below how would you call the Downloader
async function in a test context:下面是一个简单的示例,您将如何在测试上下文中调用
Downloader
异步函数:
class DataDownloaderTests: XCTestCase {
func testDataDownload() async throws {
let dataDownloader = DataDownloader()
let downloadedData = try await dataDownloader.downloadData()
XCTAssertNil(resizedImage.size)
}
}
func AsyncFunction() async -> Int {
let result = await AsyncOperation()
return result
}
let scheduler = TestScheduler()
let result = try scheduler.start {
return try AsyncFunction().wait()
}
XCTAssertEqual(result, 42)
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