在单元测试中模拟iOS App版本号

Question

I have added functionality to my project that downloads JSON and compares the version numbers in there with the currently installed app version to determine whether a feature should be enabled or not. However, I am now trying to unit test this and I am not sure how to mock the current app version.

• Can I inject a value into the info.plist in a test?
• Can I completely mock the info.plist in a test?

Or should I:

• Add a function in my class to retrieve the version number from the info.plist file and then mock that function?

• On app startup, store the version number in NSUserDefaults and the mock this?

Answer 1

I would definitely go with the function which retrieves version number. This way you can get it from info.plist in production code and mock whatever you want in tests. Additionally you will be able to test the retrieval of app version as well :)

Or even better, create another class which gets the application number and inject instance to the class which downloads JSONs. You'll be then able to mock this however you want.

protocol AppVersionProvider {
    func getAppVersion() -> String
}

class JSONDownloader {

    private let appVersionProvider: AppVersionProvider

    public init(appVersionProvider: AppVersionProvider) {
        self.appVersionProvider = appVersionProvider
    }

    public func downloadJSON() {

        if appVersionProvider.getAppVersion() != networkingCallResult.appVersion {
            ...
        }
    }
}

There, you can mock AppVersionProvider protocol in test with some stub and use info.plist provider for production.