New Compose testing API just dropped in 1.7.0-alpha01!
`DeviceConfigurationOverride` is the successor to accompanist/test-harness and allows locally overriding aspects of the device's configuration for @Composable content under test.
Font scale, font weight, dark mode, locale, layout direction, and size are all device-wide properties, so it's difficult to test for them (updating system settings from a test is not fun), but they're also super important to test for!
Want to test a component in right-to-left?
DeviceConfigurationOverride(DeviceConfigurationOverride.LayoutDirection(LayoutDirection.Rtl)) {
MyComponent() // will be rendered with a right-to-left layout direction
}
Want to test a component with an increased font scale?
DeviceConfigurationOverride(DeviceConfigurationOverride.FontScale(1.5f)) {
MyComponent()
}
Size is my favorite one:
DeviceConfigurationOverride(
DeviceConfigurationOverride.ForcedSize(DpSize(1280.dp, 800.dp))
) {
MyScreen() // will be rendered in the space for 1280dp by 800dp without clipping
}
Through a bit of trickery by overriding the density, MyScreen() will be guaranteed to have 1280dp by 800dp space to render, regardless of the actual device size.
You can test layouts big and small on a single test device!
Alex Vanyo (he/him)
Matt