Write Unit Tests to validate WKWebView load request - ios

Question

I have a WKWebView to loads a basic url request.
extension ViewController: WKUIDelegate, WKScriptMessageHandler, WKNavigationDelegate {
func webView(
_ webView: WKWebView,
createWebViewWith configuration: WKWebViewConfiguration,
for navigationAction: WKNavigationAction,
windowFeatures: WKWindowFeatures
) -> WKWebView? {
if navigationAction.targetFrame == nil, let url = navigationAction.request.url {
if url.description.lowercased().range(of: "http://") != nil ||
url.description.lowercased().range(of: "https://") != nil ||
url.description.lowercased().range(of: "mailto:") != nil {
UIApplication.shared.open(url)
}
}
return nil
}
func openSite() {
guard let myUrl = URL(string: "https://www.myurl.com") else { return }
let request = URLRequest(url: myUrl)
webView?.load(request)
self.webView.sizeToFit()
}
Now I want to write a unit test to verify webview correctly load the request. I have followed this approach https://stackoverflow.com/a/63827560/627667 and created a mock navigation action.
func test_AllowsCorrectURL() {
let action = MockNavigationAction()
action.mockedRequest = URLRequest(url: URL(string: "https://www.myurl")!)
let allowExpectation = expectation(description: "Allows action")
viewController.webView(WKWebView(), decidePolicyFor: action) { policy in
XCTAssertEqual(policy, .allow)
allowExpectation.fulfill()
}
waitForExpectations(timeout: 1.0)
}
However on this line viewController.webView(WKWebView(), decidePolicyFor: action) I am getting below error.
Cannot call value of non-function type 'WKWebView?'
Swift version 5. How to get rid of this error? Your suggestions highly appreciated.

Answer 1

I'm almost sure that this is related to you adding implementation for another method of WKNavigationDelegate to your vc. It has few of them containing decidePolicyFor parameter label and if you will omit the implementation for the one that you are trying to call in here you won't be able to do so.
The reason of that (to my understanding) is that these are methods marked as optional on the protocol so your class doesn't need to implement them and if compiler won't find implementation of the method that you try to call it will complete with the error.
Since you shared a concrete example, you're basing your solution on check if your vc is having a method with exactly this signature:
extension ViewController: WKNavigationDelegate {
func webView(
_ webView: WKWebView,
decidePolicyFor navigationAction: WKNavigationAction,
decisionHandler: #escaping (WKNavigationActionPolicy) -> Void) {
// ...
}
}