Support @Preview param "apiLevel"

[sergio-sastre]

Now that Robolectric 1.14 is out with support for TestParameterInjector, supporting apiLevel in the very same test class should be feasible.

I'll try to explore it and create a PR once I find the time

[sergio-sastre]

This is an example of something I've just got working to showcase the idea behind:

private val cachedPreviews: List<ComposablePreview<AndroidPreviewInfo>> by lazy {
    AndroidComposablePreviewScanner()
        .scanPackageTrees("snapshot.testing.lazycolumn_previews.roborazzi")
        .includeAnnotationInfoForAllOf(RoborazziConfig::class.java)
        .getPreviews()
}

// One needs to generate one ComposablePreviewProvider per apiLevel
object ComposablePreviewProviderApi35 : TestParameterValuesProvider() {
    override fun provideValues(context: Context?): List<ComposablePreview<AndroidPreviewInfo>> =
        // apiLevel default = -1 -> renders with 35
        cachedPreviews.filter { it.previewInfo.apiLevel < 28 || it.previewInfo.apiLevel == 35 }
}

object ComposablePreviewProviderApi31 : TestParameterValuesProvider() {
    override fun provideValues(context: Context?): List<ComposablePreview<AndroidPreviewInfo>> =
        cachedPreviews.filter { it.previewInfo.apiLevel == 31 }
}
...

@RunWith(RobolectricTestParameterInjector::class)
class PaparazziComposePreviewTests {
    @get:Rule
    val composeTestRule = createAndroidComposeRule<ComponentActivity>()

    private fun snapshot(preview: ComposablePreview<AndroidPreviewInfo>) {
        composeTestRule.configureFor(preview)

        composeTestRule
            .apply { setContent { preview() } }
            .onRoot()
            .captureRoboImage(
                filePath = filePath(AndroidPreviewScreenshotIdBuilder(preview).build()),
                roborazziOptions = RoborazziOptionsMapper.createFor(preview)
            )
    }

   // Generate 1 Test per apiLevel
    @GraphicsMode(NATIVE)
    @Config(sdk = [35])
    @Test
    fun snapshotApi35(
        @TestParameter(valuesProvider = ComposablePreviewProviderApi35::class)
        preview: ComposablePreview<AndroidPreviewInfo>,
    ) {
        snapshot(preview)
    }

    @GraphicsMode(NATIVE)
    @Config(sdk = [31])
    @Test
    fun snapshotApi31(
        @TestParameter(valuesProvider = ComposablePreviewProviderApi31::class)
        preview: ComposablePreview<AndroidPreviewInfo>,
    ) {
        snapshot(preview)
    }
    ...
}