Say I have a composable with a text like this:

val ItemKey = SemanticsPropertyKey<Item>("Item")
var SemanticsPropertyReceiver.item by ItemKey

data class Item(val id: Int, val name: String)

Text(
    modifier = Modifier.semantics {
        this.testTag = "test"
        this.item = Item(99, "TestXXX")
    },
    text = "My text"
)

And now in my test, I want to retrieve the

Item

object and assert its values

composeTestRule.onNodeWithTag("test").assert(???, 99)

Anyone has a tip for how to do that?

There are other SemanticsMatchers for other things, and you can write your own assertions - just look at how the ones in the stdlib are implemented

For reference if someone else is looking for this. you can create your own assert helper method. for above example it could look like this

fun SemanticsNodeInteraction.assertItem(description: String, check: (Item) -> Boolean) {
    assert(SemanticsMatcher(description) {
        check(it.config[ItemKey])
    })
}

and then i can write my tests like this

composeTestRule.onNodeWithTag("test").assertItem("Checking id") {
    it.id == 99
}