BaselineProfileRule

@RequiresApi(value = 28)
class BaselineProfileRule : TestRule

A TestRule that collects Baseline Profiles to be embedded in your APK.

These rules are used at install time to partially pre-compile your application code.

BaselineProfileRule is only supported on Android 13 (API 33) and above, or if using a rooted device, Android P (API 28) and above.

@RunWith(AndroidJUnit4::class)
class BaselineProfileGenerator {
    @get:Rule
    val baselineProfileRule = BaselineProfileRule()

    @Test
    fun startup() = baselineProfileRule.collect(
        packageName = "com.example.my.application.id"
    ) {
        pressHome()
        // This block defines the app's critical user journey. Here we are
        // interested in optimizing for app startup, but you can also navigate
        // and scroll through your most important UI.
        startActivityAndWait()
    }
}

Note that you can filter captured rules, for example, if you're generating rules for a library, and don't want to record profiles from outside that library:

    @Test
    fun generateLibraryRules() = baselineProfileRule.collect(
        // Target app is an integration test app which uses the library, but any
        // app code isn't relevant to store in library's Baseline Profile
        packageName = "com.example.testapp.id"
        filterPredicate = {
            // Only capture rules in the library's package, excluding test app code
            // Rules are prefixed by tag characters, followed by JVM method signature,
            // e.g. `HSPLcom/mylibrary/LibraryClass;-><init>()V`, where `L`
            // signifies the start of the package/class, and '/' is divider instead of '.'
            val libPackage = "com.mylibrary"
            it.contains("^.*L${libPackage.replace(".", "/")}".toRegex())
        },
    ) {
        // ...
    }

See the Baseline Profile Guide for more information on creating Baseline Profiles.

Summary

BaselineProfileRule()

open fun apply(base: Statement, description: Description): Statement

fun collect(
    packageName: String,
    maxIterations: Int = 15,
    stableIterations: Int = 3,
    outputFilePrefix: String? = null,
    includeInStartupProfile: Boolean = false,
    strictStability: Boolean = false,
    filterPredicate: (String) -> Boolean = { true },
    profileBlock: MacrobenchmarkScope.() -> Unit
): Unit