Write automated tests with UI Automator

The UI Automator testing framework provides a set of APIs to build UI tests that interact with user apps and system apps.

Introduction to modern UI Automator testing

UI Automator 2.4 introduces a streamlined, Kotlin-friendly Domain Specific Language (DSL) that simplifies writing UI tests for Android. This new API surface focuses on predicate-based element finding and explicit control over app states. Use it to create more maintainable and reliable automated tests.

UI Automator lets you test an app from outside of the app's process. This lets you test release versions with minification applied. UI Automator also helps when writing macrobenchmark tests.

Key features of the modern approach include:

• A dedicated uiAutomator test scope for cleaner and more expressive test code.
• Methods like onElement, onElements, and onElementOrNull for finding UI elements with clear predicates.
• Built-in waiting mechanism for conditional elements onElement*(timeoutMs: Long = 10000)
• Explicit app state management such as waitForStable and waitForAppToBeVisible.
• Direct interaction with accessibility window nodes for multi-window testing scenarios.
• Built-in screenshot capabilities and a ResultsReporter for visual testing and debugging.

Set up your project

To begin using the modern UI Automator APIs, update your project's build.gradle.kts file to include the latest dependency:

dependencies {
  ...
  androidTestImplementation("androidx.test.uiautomator:uiautomator:2.4.0-alpha05")
}

dependencies {
  ...
  androidTestImplementation "androidx.test.uiautomator:uiautomator:2.4.0-alpha05"
}

Core API concepts

The following sections describe core concepts of the modern UI Automator API.

The uiAutomator test scope

Access all new UI Automator APIs within the uiAutomator { ... } block. This function creates a UiAutomatorTestScope that provides a concise and type-safe environment for your test operations.

uiAutomator {
  // All your UI Automator actions go here
  startApp("com.example.targetapp")
  onElement { textAsString() == "Hello, World!" }.click()
}

Find UI elements

Use UI Automator APIs with predicates to locate UI elements. These predicates let you define conditions for properties such as text, selected or focused state, and content description.

• onElement { predicate }: Returns the first UI element that matches the predicate within a default timeout. The function throws an exception if it doesn't locate a matching element.

  // Find a button with the text "Submit" and click it
  onElement { textAsString() == "Submit" }.click()
  
  // Find a UI element by its resource ID
  onElement { id == "my_button_id" }.click()
  
  // Allow a permission request
  watchFor(PermissionDialog) {
    clickAllow()
  }
  

• onElementOrNull { predicate }: Similar to onElement, but returns null if the function finds no matching element within the timeout. It doesn't throw an exception. Use this method for optional elements.

  val optionalButton = onElementOrNull { textAsString() == "Skip" }
  optionalButton?.click() // Click only if the button exists
  

• onElements { predicate }: Waits until at least one UI element matches the given predicate, then returns a list of all matching UI elements.

  // Get all items in a list Ui element
  val listItems = onElements { className == "android.widget.TextView" && isClickable }
  listItems.forEach { it.click() }
  

Here are some tips for using onElement calls:

• Chain onElement calls for nested elements: You can chain onElement calls to find elements within other elements, following a parent-child hierarchy.

  // Find a parent Ui element with ID "first", then its child with ID "second",
  // then its grandchild with ID "third", and click it.
  onElement { id == "first" }
    .onElement { id == "second" }
    .onElement { id == "third" }
    .click()
  

• Specify a timeout for onElement* functions by passing a value representing milliseconds.

  // Find a Ui element with a zero timeout (instant check)
  onElement(0) { id == "something" }.click()
  
  // Find a Ui element with a custom timeout of 10 seconds
  onElement(10_000) { textAsString() == "Long loading text" }.click()
  

Interact with UI elements

Interact with UI elements by simulating clicks or setting text in editable fields.

// Click a Ui element
onElement { textAsString() == "Tap Me" }.click()

// Set text in an editable field
onElement { className == "android.widget.EditText" }.setText("My input text")

// Perform a long click
onElement { contentDescription == "Context Menu" }.longClick()

Handle app states and watchers

Manage the lifecycle of your app and handle unexpected UI elements that might appear during your tests.

App lifecycle management

The APIs provide ways to control the state of the app under test:

// Start a specific app by package name. Used for benchmarking and other
// self-instrumenting tests.
startApp("com.example.targetapp")

// Start a specific activity within the target app
startActivity(SomeActivity::class.java)

// Start an intent
startIntent(myIntent)

// Clear the app's data (resets it to a fresh state)
clearAppData("com.example.targetapp")

Handle unexpected UI

The watchFor API lets you define handlers for unexpected UI elements, such as permission dialogs, that might appear during your test flow. This uses the internal watcher mechanism but offers more flexibility.

import androidx.test.uiautomator.PermissionDialog

@Test
fun myTestWithPermissionHandling() = uiAutomator {
  startActivity(MainActivity::class.java)

  // Register a watcher to click "Allow" if a permission dialog appears
  watchFor(PermissionDialog) { clickAllow() }

  // Your test steps that might trigger a permission dialog
  onElement { textAsString() == "Request Permissions" }.click()

  // Example: You can register a different watcher later if needed
  clearAppData("com.example.targetapp")

  // Now deny permissions
  startApp("com.example.targetapp")
  watchFor(PermissionDialog) { clickDeny() }
  onElement { textAsString() == "Request Permissions" }.click()
}

PermissionDialog is an example of a ScopedWatcher<T>, where T is the object passed as a scope to the block in watchFor. You can create custom watchers based on this pattern.

Wait for app visibility and stability

Sometimes tests need to wait for elements to become visible or stable. UI Automator offers several APIs to help with this.

The waitForAppToBeVisible("com.example.targetapp") waits for a UI element with the given package name to appear on the screen within a customizable timeout.

// Wait for the app to be visible after launching it
startApp("com.example.targetapp")
waitForAppToBeVisible("com.example.targetapp")

Use the waitForStable() API to verify that the app's UI is considered stable before interacting with it.

// Wait for the entire active window to become stable
activeWindow().waitForStable()

// Wait for a specific Ui element to become stable (e.g., after a loading animation)
onElement { id == "my_loading_indicator" }.waitForStable()

Advanced features

The following features are useful for more complex testing scenarios.

Interact with multiple windows

The UI Automator APIs let you directly interact with and inspect UI elements. This is particularly useful for scenarios involving multiple windows, such as Picture-in-Picture (PiP) mode or split-screen layouts.

// Find the first window that is in Picture-in-Picture mode
val pipWindow = windows()
  .first { it.isInPictureInPictureMode == true }

// Now you can interact with elements within that specific window
pipWindow.onElement { textAsString() == "Play" }.click()

Screenshots and visual assertions

Capture screenshots of the entire screen, specific windows, or individual UI elements directly within your tests. This is helpful for visual regression testing and debugging.

uiautomator {
  // Take a screenshot of the entire active window
  val fullScreenBitmap: Bitmap = activeWindow().takeScreenshot()
  fullScreenBitmap.saveToFile(File("/sdcard/Download/full_screen.png"))

  // Take a screenshot of a specific UI element (e.g., a button)
  val buttonBitmap: Bitmap = onElement { id == "my_button" }.takeScreenshot()
  buttonBitmap.saveToFile(File("/sdcard/Download/my_button_screenshot.png"))

  // Example: Take a screenshot of a PiP window
  val pipWindowScreenshot = windows()
    .first { it.isInPictureInPictureMode == true }
    .takeScreenshot()
  pipWindowScreenshot.saveToFile(File("/sdcard/Download/pip_screenshot.png"))
}

The saveToFile extension function for Bitmap simplifies saving the captured image to a specified path.

Use ResultsReporter for debugging

The ResultsReporter helps you associate test artifacts, like screenshots, directly with your test results in Android Studio for easier inspection and debugging.

uiAutomator {
  startApp("com.example.targetapp")

  val reporter = ResultsReporter("MyTestArtifacts") // Name for this set of results
  val file = reporter.addNewFile(
    filename = "my_screenshot",
    title = "Accessible button image" // Title that appears in Android Studio test results
  )

  // Take a screenshot of an element and save it using the reporter
  onElement { textAsString() == "Accessible button" }
    .takeScreenshot()
    .saveToFile(file)

  // Report the artifacts to instrumentation, making them visible in Android Studio
  reporter.reportToInstrumentation()
}

Migrate from older UI Automator versions

If you have existing UI Automator tests written with older API surfaces, use the following table as a reference to migrate to the modern approach: