Timeouts on WKWebView image snapshot

[kaqu]

Hi, one more issue from me 😇 It looks like WKWebView is never performing image snapshot when there is no content loaded. I have the case where one of my views contains WKWebView that have no content initially. If I've debugged that correctly image snapshot on web view waits until the page finishes loading. But when there is no page loading it never occurs resulting in a timeout.
I am wondering if making it possible to take a snapshot when there is no content in web view is a good solution here.
Workaround for this is to load any file from disk into, even empty one.

[stephencelis]

Ah, good point, embedded web views shouldn’t time out if possible. Will look into this soon! Thanks for so thoroughly testing things 🙌

[kaqu]

Applications I am covering now with snapshot tests (fortunately) have a lot of weird things 😅

[stephencelis]

@kaqu I can't seem to reproduce this failure. WKWebView snapshots should only time out if the web view thinks that it isLoading. As long as the web view is not actively loading content, it should render a blank screen. Any chance you can produce a failing test case for us?

[kaqu]

Ok, I will try to reproduce it outside or find if there is some other case here.

[kaqu]

This makes timeout:

func testWebView() {
        class VC: UIViewController {
            override func loadView() {
                let browser: WKWebView = .init()
                view = browser
                browser.load(URLRequest(url: URL(string: "url")!))
            }
        }
        let vc = VC()
        vc.view.frame = .init(x: 0, y: 0, width: 200, height: 200)
        assertSnapshot(matching: vc, as: .image)
    }

It turns out that it was loading url, but it was kind of invalid.

[kaqu]

I am wondering if loading other valid URL like base64 data which is accepted by browsers will behave similarly.

[stephencelis]

Ah. I think it’s kind of correct to fail in this case. Any way to modify your code to avoid the loading for the test? Or to load a valid HTML string instead?

[stephencelis]

(Up for other suggestions, too! We just want to wait for loading web pages to load.)

[kaqu]

Thanks for help though, sorry for incomplete debug 🙂 I agree that timeout in that case is good (loading base64 data seems to work correctly)

[stephencelis]

Going to close this issue and track the improvement here #136.