Control your app from Macrobenchmark

Unlike most Android UI tests, Macrobenchmark tests run in a separate process from the app itself. This is necessary to enable things like stopping the app process and compiling from DEX bytecode to machine code.

You can drive your app's state using the UIAutomator library or other mechanisms that can control the target app from the test process. You can't use Espresso or ActivityScenario for Macrobenchmark because they expect to run in a shared process with the app.

The following example finds a RecyclerView using its resource ID and scrolls down several times:

@Test
fun scrollList() {
    benchmarkRule.measureRepeated(
        // ...
        setupBlock = {
            // Before starting to measure, navigate to the UI to be measured
            val intent = Intent("$packageName.RECYCLER_VIEW_ACTIVITY")
            startActivityAndWait(intent)
        }
    ) {
        val recycler = device.findObject(By.res(packageName, "recycler"))
        // Set gesture margin to avoid triggering gesture navigation
        // with input events from automation.
        recycler.setGestureMargin(device.displayWidth / 5)

        // Scroll down several times
        repeat(3) { recycler.fling(Direction.DOWN) }
    }
}
FrameTimingBenchmark.kt

@Test
public void scrollList() {
    benchmarkRule.measureRepeated(
        // ...
        /* setupBlock */ scope -> {
            // Before measuring, navigate to the UI to be measured.
            val intent = Intent("$packageName.RECYCLER_VIEW_ACTIVITY")
            scope.startActivityAndWait();
            return Unit.INSTANCE;
        },
        /* measureBlock */ scope -> {
            UiDevice device = scope.getDevice();
            UiObject2 recycler = device.findObject(By.res(scope.getPackageName(), "recycler"));

            // Set gesture margin to avoid triggering gesture navigation
            // with input events from automation.
            recycler.setGestureMargin(device.getDisplayWidth() / 5);

            // Fling the recycler several times.
            for (int i = 0; i < 3; i++) {
                recycler.fling(Direction.DOWN);
            }

            return Unit.INSTANCE;
        }
    );
}

Your benchmark doesn't have to scroll the UI. Instead, it can run an animation, for example. It also doesn't need to use UI Automator specifically. It collects performance metrics as long as frames are being produced by the view system, including frames produced by Jetpack Compose.

Navigate to internal parts of the app

Sometimes you want to benchmark parts of your app that aren't directly accessible from outside. This might be, for example, accessing inner Activities that are marked with exported=false, navigating to a Fragment, or swiping some part of your UI away. The benchmarks need to manually navigate to these parts of the app like a user.

To manually navigate, change the code inside setupBlock{} to contain the effect you want, such as button tap or swipe. Your measureBlock{} contains only the UI manipulation you want to actually benchmark:

@Test
fun nonExportedActivityScrollList() {
    benchmarkRule.measureRepeated(
        // ...
        setupBlock = setupBenchmark()
    ) {
        // ...
    }
}

private fun setupBenchmark(): MacrobenchmarkScope.() -> Unit = {
    // Before starting to measure, navigate to the UI to be measured
    startActivityAndWait()

    // click a button to launch the target activity.
    // While we use button text  here to find the button, you could also use
    // accessibility info or resourceId.
    val selector = By.text("RecyclerView")
    if (!device.wait(Until.hasObject(selector), 5_500)) {
        fail("Could not find resource in time")
    }
    val launchRecyclerActivity = device.findObject(selector)
    launchRecyclerActivity.click()

    // wait until the activity is shown
    device.wait(
        Until.hasObject(By.clazz("$packageName.NonExportedRecyclerActivity")),
        TimeUnit.SECONDS.toMillis(10)
    )
}
NonExportedActivityBenchmark.kt

@Test
public void scrollList() {
    benchmarkRule.measureRepeated(
        // ...
        /* setupBlock */ scope -> {
            // Before measuring, navigate to the default activity.
            scope.startActivityAndWait();

            // Click a button to launch the target activity.
            // While you use resourceId here to find the button, you can also
            // use accessibility info or button text content.
            UiObject2 launchRecyclerActivity = scope.getDevice().findObject(
                By.res(packageName, "launchRecyclerActivity")
            )
            launchRecyclerActivity.click();

            // Wait until activity is shown.
            scope.getDevice().wait(
                Until.hasObject(By.clazz("$packageName.NonExportedRecyclerActivity")),
                10000L
            )

            return Unit.INSTANCE;
        },
        /* measureBlock */ scope -> {
            // ...
        }
    );
}