Testing with different Locales and Font Scales

Locales

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

When using ComposableScreenshotRule, you can invoke the setLocale() method to set the Locale used in your test. setLocale accepts any valid Locale instance.

Example

    // In the res/values/strings.xml file
    // <string name="example">A short example</string>

    // In the res/values-fr/strings.xml file
    // <string name="example">Un petit exemple</string>

    @ScreenshotInstrumentation
    @Test
    fun localeFrance() {
        rule
            .setCompose {
                Text(stringResource(R.string.example))
            }
            .setLocale(Locale.FRANCE)
            .assertSame()
    }

Font Scale

Testify allows you to change the current scaling factor for fonts, relative to the base density scaling. This allows you to simulate the impact of a user modifying the default font size on their device, such as tiny, large or huge.

See Font size and display size

To modify the font scale in a single test, use the setFontScale() method.

    @ScreenshotInstrumentation
    @Test
    fun largeFontScale() {
        rule
            Text(
                text = "Test",
                fontSize = 16.sp
            )
            .setFontScale(3.0f)
            .assertSame()
    }