Unit testing WKNavigationDelegate functions

Question

I have a UIViewController that implements some WKNavigationDelegate functions, and I want to unit test the logic in these functions. Here\'s an example:

func         


        

Answer 1

Directly calling the delegate method is the most appropriate approach in the context of a unit test. You can subclass WKNavigationAction, and pass an instance of that class as input argument to the delegate method:

class FakeNavigationAction: WKNavigationAction {
    let testRequest: URLRequest
    override var request: URLRequest {
        return testRequest
    }

    init(testRequest: URLRequest) {
        self.testRequest = testRequest
        super.init()
    }
}

Later on, in the unit test:

// setup
var receivedPolicy: WKNavigationActionPolicy?
let fakeAction = FakeNavigationAction(testRequest: ...)

// act
delegateObject.webView(webView, decidePolicyFor: fakeAction, decisionHandler: { receivedPolicy = $0 })

// assert
XCTAssertEqual(receivedPolicy, theExpectedValue)

Another approach would be to swizzle the getter for request, since WKNavigationAction is an Objective-C class, however that's more of a hacky solution.