Determine if debug build, TestFlight build, or AppStore build

You can use the following code snippets to determine whether your app is running in debug mode or if it is a TestFlight version. This can be quite useful if you want to add a debug menu or something like this internally.

// Will be true when the build is in TestFlight (running an app download from TestFlight)
let isTestFlight = NSBundle.mainBundle().appStoreReceiptURL?.lastPathComponent == "sandboxReceipt"

// Will be true when the build is a debug build (usually when running from Xcode directly)
static var isDebug: Bool {
    #if DEBUG
      return true
    #else
      return false
    #endif
}