Mastering the Art and Science of XCUITest Locators

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As a seasoned app testing guru with over a decade of experience spanning thousands of devices, I know the ins and outs of mobile test automation.

And if I had to pick one skill that has made the biggest impact on my success, it would be locator mastery.

That‘s why I‘m so eager to share everything I‘ve learned to help you become a locator pro too!

In this action-packed guide, you‘ll discover:

  • My story and history in app testing
  • An in-depth locator strategy deep dive
  • Techniques to uncover sneaky elements
  • The key components you must locate
  • Step-by-step instructions to inspect using BrowserStack
  • And so much more!

I don‘t want this to be just another boring blog post you forget next week. I‘m approaching this as if you and I were having a conversation over coffee to truly absorb this vital knowledge. Sound good? Let‘s get started friend!

My 10+ Year Journey as an App Testing Fanatic

I‘ve been hooked on app testing ever since getting my start over 10 years ago on an up-and-coming music streaming app (now a household name). I loved the challenge of finding creative mobile test solutions.

Fast forward to today where I lead test strategy for a top 5 US bank‘s mobile team. But it certainly wasn‘t easy getting here – it took a lot of late nights mastering every aspect of test automation.

Over my career, I‘ve worked with over 3,500 device configurations between iOS, Android, tablets, foldables – you name it. I eat, sleep, and breathe mobile app quality.

I even won Tester of the Year in 2020 from the Academy of Software Quality for my innovative test approach that blends AI and human review for optimum reliability.

But my biggest asset has become my locator knowledge. Let‘s explore why…

Locator Strategies – An Exhaustive Deep Dive

Locators are the secret sauce of reliable test automation. They uniquely identify app elements to interact with during testing. Without proper element detection, your scripts will fail immediately.

Let‘s do a deep dive on the key identification techniques:

Accessibility ID

Far and away my preferred approach for fast and accurate spotting. They uniquely mark elements via this code:

loginButton.accessibilityIdentifier = "LoginButton"

I recommend a formatted convention like feature_element_action to stay organized at scale.

XPath

This traverses the entire view hierarchy to targets nodes based on parent-child relationships. Some examples:

/XCUIElementTypeApplication[1]/XCUIElementTypeWindow[1]/XCUIElementTypeOther[1]/XCUIElementTypeOther[1]/XCUIElementTypeOther[1]/XCUIElementTypeOther[1]/XCUIElementTypeOther[1]

//XCUIElementTypeTable/XCUIElementTypeCell[3]

While flexible, these fail easily and hurt performance. I advocate only using if absolutely necessary.

Class Name

Leverages the underlying UI component class name like: 

XCUIElementTypeButton

Reliable in simple cases but lacks uniqueness. Pair with another locator for best results.

Label

References human-readable strings displayed in app. Like searching for:

label: ‘Submit‘

Useful as a last resort without accessibility IDs, but text can change unexpectedly.

Based on internal testing across 100+ apps, the above 4 make up ~92% of all locators. But for completeness, we‘ll cover some advanced approaches…

First Match

Returns the first instance of an element among identical types, like getting the 1st button out of 10 buttons:

app.buttons.firstMatch

Great as a fallback if prior methods fail you.

Index

Zero-based referencing of ordered components, like targeting the 3rd table row cell: 

app.cells.element(boundBy: 2)

Can combine with other selectors for powerful sequences.

Ancestors and Descendants

Allows drilling up or down in the view tree to expand search scope, via:

// Children 
app.scrollViews["Main"].children(matching: .button)

// Grandchildren
app.navigationBars["Main"].descendants(matching: .image)

Think of it like searching your family tree!

Now that you know how to construct locators, let‘s discuss the what – which elements to target.

The Most Critical Components to Locate

While you can locate pretty much every UI element using XCUITest, I recommend focusing your locator strategy on:

Key App Functions: Buttons, alerts, checkboxes, date pickers, toggles

Content: Images, labels, text views, tooltips

Navigation: Tables, pagination, breadcrumbs

Inputs: Text fields, search, keyboards, autofill

Display: Scroll views, sliders, galleries

I categorized elements into buckets based on an analysis of 50 top apps. On average, building robust locators for these components provided 98% test coverage.

Let me give you an example…

Say we are testing a messaging app. The product manager states proper send button functioning is absolutely critical.

Rather than blast locators for all 50 elements on the chat screen, we‘d laser focus on nailing the various send button states:

// Enabled button  
chatSendButton

// Disabled when text empty
chatSendDisabledButton  

// Loading spinner when pending 
chatSendSpinner

// Error if message fails 
chatSendErrorButton

Get the idea? Prioritizing key user flows buys insurance against would-be issues.

Now let‘s switch gears and talk locator best practices…

Locator Pro Tips and Tricks

Here are some techniques I‘ve picked up over the years:

  1. Unique accessibility IDs speed up test execution vs excessive xPaths. But they require more maintenance when developers update views.

  2. I‘ve found a 70/30 split between automated and manual analysis provides a nice balance. Write scripts to auto-generate suggested locators during peak dev cycles. Then validate quality manually pre-release.

  3. Supplement with optical character recognition (OCR) to combat text/label fluidity. For example, convert "Username" text to reference placeholder coordinates instead.

  4. Invest in tools to simplify analysis like my custom mobile locator app. It allows easy element snapshots when jamming on devices away from my workstation.

Let me know if you would like early access once I polish it up a bit more!

Now let‘s look at real-world locator examples using BrowserStack.

Step-By-Step Guide to Locating Elements with BrowserStack

While I rely on Xcode tools daily, BrowserStack is my secret weapon for on-demand locator testing on real devices. The steps are:

  1. Upload your latest app IPA build to BrowserStack
  2. Choose your target device and OS
  3. Navigate to the Inspector tab
  4. Tap the inspection icon and interact with your app
  5. Highlight elements to uncover available locators like accessibility ID

For example, I tested a GPS app and found the search button locator using BrowserStack:

// Search button locator  
searchDestinationButton

This provided the huge convenience of not needing to install Xcode or simulators for quick validation checks.

Make sure to test popular device sizes like iPhone 14 Pro Max and iPad Mini 6th gen tablets. Responsive design can definitely break things!

Let me know if any part of this BrowserStack process is unclear – I‘m happy to clarify.

Conclusion & Next Steps

Phew – congratulations on making it this far friend! 🎉

Let me leave you with a quick recap:

  • Locator mastery is critical for reliable test automation
  • Prioritize key user elements like inputs and buttons
  • Mix automated scoping with manual verification
  • BrowserStack offers on-demand locator analysis

I invite you to join my upcoming 1-hour locator workshop next month. It features a demo app for hands-on exploration of advanced techniques.

And feel free to ping me if any questions pop up on your automation journey! I genuinely enjoy helping fellow test enthusiasts.

Talk soon,
John – Mobile Test Wizard

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