Fastlane is collection of incredibly helpful tools built by Felix Krause.

This week, Twitter announced that Fastlane would be joining their already-great Fabric suite of tools. Congrats Felix! 🎉

We'll be taking a look at some of Fastlane's tools individually in the coming weeks. Today we'll begin with snapshot.

If we're being good localization citizens in our apps, we could have something like 20 or more languages that we support. We also want to market our app well, so we use all 5 screenshot slots on the App Store. Oh, and we support lots of different iOS devices. Ack!

This all adds up to potentially hundreds of new screenshots to capture and upload each release. We better make sure we get the status bar looking clean, and not accidentally capture any loading snippers, etc. Eesh. That sounds like a whole lot of time spent not building apps. Let's see how we can use snapshot to save our sanity:

snapshot uses Xcode 7's UI Testing functionality (Bite #30) to help us automate our apps and specify exactly when to capture screenshots. It also makes sure they look great with presentable status bars, etc.

Let's use the springboard app we created in Bite #104 to try it out.

We'll install the snapshot gem, then head into our app's main directory and run snapshot init.

This will create a SnapshotHelper.swift file we'll need to add to the UI Test target in our project.

Instead of calling launch on XCUIApplication() directly, we need to plug snapshot into the mix by calling setLanguage on our app, then launching it. In our test, we'll snap a screenshot of the initial screen and give it a name.

class SnapshotTests: XCTestCase {
  override func setUp() {
    super.setUp()

    continueAfterFailure = false

    let app = XCUIApplication()
    setLanguage(app)
    app.launch()
  }

  func testExample() {
    snapshot("01MainScreen")
  }
}

Now we just head into our app's directory and run snapshot.

Our screenshots will be captured, and saved to disk. We can check out the results in Finder.

To configure the list of devices and languages that will be captured we can add the Snapfile that was created earlier when we ran snapshot init to our project as well and customize it to our needs.

More info about snapshot can be found at git.io/snapshot.