Custom assertions for testing Jetpack Compose custom action labels and callbacks

SemanticsNodeInteractionExtension.kt

fun SemanticsNodeInteraction.assertHasCustomActionLabel(
    label: String,         // Assert the label matches
    actionIndex: Int = 0   // Which action to verify, if you have more than one
): SemanticsNodeInteraction = assert(SemanticsMatcher("The custom accessibility action label is set to $label") {
    it.config
        .getOrNull(SemanticsActions.CustomActions)
        ?.get(actionIndex)?.label == label
})

fun SemanticsNodeInteraction.invokeCustomAction(
    actionIndex: Int = 0   // Which action to invoke, if you have more than one
): SemanticsNodeInteraction = assert(SemanticsMatcher("The custom accessibility action is invoked") {
    val action = it.config
        .getOrNull(SemanticsActions.CustomActions)
        ?.get(actionIndex)?.action ?: return@SemanticsMatcher false

    action.invoke()
})