UI Testing

Overview

Wait for conditions, not arbitrary timeouts. Core principle Flaky tests come from guessing how long operations take. Condition-based waiting eliminates race conditions.

NEW in WWDC 2025: Recording UI Automation allows you to record interactions, replay across devices/languages, and review video recordings of test runs.

Example Prompts

These are real questions developers ask that this skill is designed to answer:

1. "My UI tests pass locally on my Mac but fail in CI. How do I make them more reliable?"

→ The skill shows condition-based waiting patterns that work across devices/speeds, eliminating CI timing differences

2. "My tests use sleep(2) and sleep(5) but they're still flaky. How do I replace arbitrary timeouts with real conditions?"

→ The skill demonstrates waitForExistence, XCTestExpectation, and polling patterns for data loads, network requests, and animations

3. "I just recorded a test using Xcode 26's Recording UI Automation. How do I review the video and debug failures?"

→ The skill covers Video Debugging workflows to analyze recordings and find the exact step where tests fail

4. "My test is failing on iPad but passing on iPhone. How do I write tests that work across all device sizes?"

→ The skill explains multi-factor testing strategies and device-independent predicates for robust cross-device testing

5. "I want to write tests that are not flaky. What are the critical patterns I need to know?"

→ The skill provides condition-based waiting templates, accessibility-first patterns, and the decision tree for reliable test architecture

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Red Flags — Test Reliability Issues

If you see ANY of these, suspect timing issues:

• Tests pass locally, fail in CI (timing differences)
• Tests sometimes pass, sometimes fail (race conditions)
• Tests use sleep() or Thread.sleep() (arbitrary delays)
• Tests fail with "UI element not found" then pass on retry
• Long test runs (waiting for worst-case scenarios)

Quick Decision Tree

Test failing?
├─ Element not found?
│  └─ Use waitForExistence(timeout:) not sleep()
├─ Passes locally, fails CI?
│  └─ Replace sleep() with condition polling
├─ Animation causing issues?
│  └─ Wait for animation completion, don't disable
└─ Network request timing?
   └─ Use XCTestExpectation or waitForExistence

Core Pattern: Condition-Based Waiting

❌ WRONG (Arbitrary Timeout):

func testButtonAppears() {
    app.buttons["Login"].tap()
    sleep(2)  // ❌ Guessing it takes 2 seconds
    XCTAssertTrue(app.buttons["Dashboard"].exists)
}

✅ CORRECT (Wait for Condition):

func testButtonAppears() {
    app.buttons["Login"].tap()
    let dashboard = app.buttons["Dashboard"]
    XCTAssertTrue(dashboard.waitForExistence(timeout: 5))
}

Common UI Testing Patterns

Pattern 1: Waiting for Elements

// Wait for element to appear
func waitForElement(_ element: XCUIElement, timeout: TimeInterval = 5) -> Bool {
    return element.waitForExistence(timeout: timeout)
}

// Usage
XCTAssertTrue(waitForElement(app.buttons["Submit"]))

Pattern 2: Waiting for Element to Disappear

func waitForElementToDisappear(_ element: XCUIElement, timeout: TimeInterval = 5) -> Bool {
    let predicate = NSPredicate(format: "exists == false")
    let expectation = XCTNSPredicateExpectation(predicate: predicate, object: element)
    let result = XCTWaiter().wait(for: [expectation], timeout: timeout)
    return result == .completed
}

// Usage
XCTAssertTrue(waitForElementToDisappear(app.activityIndicators["Loading"]))

Pattern 3: Waiting for Specific State

func waitForButton(_ button: XCUIElement, toBeEnabled enabled: Bool, timeout: TimeInterval = 5) -> Bool {
    let predicate = NSPredicate(format: "isEnabled == %@", NSNumber(value: enabled))
    let expectation = XCTNSPredicateExpectation(predicate: predicate, object: button)
    let result = XCTWaiter().wait(for: [expectation], timeout: timeout)
    return result == .completed
}

// Usage
let submitButton = app.buttons["Submit"]
XCTAssertTrue(waitForButton(submitButton, toBeEnabled: true))
submitButton.tap()

Pattern 4: Accessibility Identifiers

Set in app:

Button("Submit") {
    // action
}
.accessibilityIdentifier("submitButton")

Use in tests:

func testSubmitButton() {
    let submitButton = app.buttons["submitButton"]  // Uses identifier, not label
    XCTAssertTrue(submitButton.waitForExistence(timeout: 5))
    submitButton.tap()
}

Why: Accessibility identifiers don't change with localization, remain stable across UI updates.

Pattern 5: Network Request Delays

func testDataLoads() {
    app.buttons["Refresh"].tap()

    // Wait for loading indicator to disappear
    let loadingIndicator = app.activityIndicators["Loading"]
    XCTAssertTrue(waitForElementToDisappear(loadingIndicator, timeout: 10))

    // Now verify data loaded
    XCTAssertTrue(app.cells.count > 0)
}

Pattern 6: Animation Handling

func testAnimatedTransition() {
    app.buttons["Next"].tap()

    // Wait for destination view to appear
    let destinationView = app.otherElements["DestinationView"]
    XCTAssertTrue(destinationView.waitForExistence(timeout: 2))

    // Optional: Wait a bit more for animation to settle
    // Only if absolutely necessary
    RunLoop.current.run(until: Date(timeIntervalSinceNow: 0.3))
}

Testing Checklist

Before Writing Tests

• Use accessibility identifiers for all interactive elements
• Avoid hardcoded labels (use identifiers instead)
• Plan for network delays and animations
• Choose appropriate timeouts (2s UI, 10s network)

When Writing Tests

• Use waitForExistence() not sleep()
• Use predicates for complex conditions
• Test both success and failure paths
• Make tests independent (can run in any order)

After Writing Tests

• Run tests 10