如何在测试用例中测试CLLocationManager的不同权限

Question

I am writing a test to test CoreLocation related function. This function will throw an error if the location services is not enabled.

func someFunction() throws {
    guard CLLocationManager.locationServicesEnabled() throw NSError.init(
            domain: kCLErrorDomain,
            code: CLError.Code.denied.rawValue,
            userInfo: nil)
    }
    ...
}

In my tests, CLLocationManager.locationServicesEnabled() is always true . Is there a way to test the false scenario?

Answer 1

Instead of using static methods directly, wrap this call in a class and make that class adopt a protocol, so your code will depend on that interface instead of the concrete implementation.

protocol LocationManager {
    var islocationServicesEnabled: Bool { get }
}

class CoreLocationManager: LocationManager {
    var islocationServicesEnabled: Bool  {
        return CLLocationManager.locationServicesEnabled()
    }
}

Then your function (or class) should receive that dependency instead of owning it (dependency injection):

func someFunction(locationManager: LocationManager) throws {
    guard locationManager.islocationServicesEnabled else {
        //...
    }
}

In your tests you can pass a "Fake" LocationManager and test all the scenarios. (In your production code you pass the CoreLocationManager.)

That's a general advice for any dependency.