Changing the Locale in a test

API 24+

It is often desirable to test your View or Activity in multiple locales. Testify allows you to dynamically change the locale on a per-test basis.

To begin, if you are targeting an emulator running Android API 24 or higher, your activity under test must implement the TestifyResourcesOverride interface. This allows Testify to attach a new Context with the appropriate locale loaded. It is highly recommended that you employ a test harness activity for this purpose. Please see the TestHarnessActivity in the provided Sample.

With an Activity which implements TestifyResourcesOverride, you can now invoke the setLocale method on the ScreenshotTestRule. setLocale accepts any valid Locale instance.

Example Test:

class TestLocaleActivityTest {

    @get:Rule var rule = ScreenshotRule(
        activityClass = TestLocaleHarnessActivity::class.java,
        launchActivity = false,
        rootViewId = R.id.harness_root
    )

    @ScreenshotInstrumentation
    @TestifyLayout(R.layout.view_client_details)
    @Test
    fun testLocaleFrance() {
        rule
            .setLocale(Locale.FRANCE)
            .assertSame()
    }
}

Example Test Harness Activity

open class TestHarnessActivity : AppCompatActivity(), TestifyResourcesOverride {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        setContentView(FrameLayout(this).apply {
            layoutParams = FrameLayout.LayoutParams(MATCH_PARENT, MATCH_PARENT)
            id = R.id.harness_root
        })
    }

    override fun attachBaseContext(newBase: Context?) {
        super.attachBaseContext(newBase?.wrap())
    }
}

Please read this excellent blog post if you want to better understand how to dynamically adjust Locale in your app. Note that the Testify locale override support is intended for instrumentation testing only and does not provide a suitable solution for your production application.

API 23 or lower

On lower API levels, a test harness activity is not required. You are not required to implement TestifyResourcesOverride, but doing so is not harmful.

To test with a provided locale, invoke the setLocale method on ScreenshotRule

Example Test:

class MainActivityScreenshotTest {

    @get:Rule var rule = ScreenshotRule(MainActivity::class.java)

    @ScreenshotInstrumentation
    @TestifyLayout(R.layout.view_client_details)
    @Test
    fun testLocaleFrance() {
        rule
            .setLocale(Locale.FRANCE)
            .assertSame()
    }
}