Compose custom semantics with multiple matchers

README.md

Unlike sample here which produces single semantics which makes it impossible to test nodes with multiple drawable ids. Following allows producing and testing multiple semantics of same type in a tree.

Usage in compose:

Modifier.semantics { drawableId = R.drawable.baseline_call_made_24 }
Modifier.semantics { drawableUrl = avatar ?: "" }

Produces tree:

Node #1
  |-Node #4
    ...
    |-Node #9
    | DrawableUrl = '[https://placekitten.com/200/100, https://placekitten.com/200/200]'
    | DrawableResId = '[2131230723, 2131230722]'
    ...

Test:

composeTestRule
    .onNode(SemanticsMatcher.keyIsDefined(SemanticsProperties.CollectionInfo))
    .onChildAt(1)
    .assert(
        hasDrawable(target1.avatar) and
                hasText(target1.cover) and
                hasDrawable(R.drawable.baseline_call_made_24) and
                hasDrawable(R.drawable.baseline_call_24)
    )
    .assertIsDisplayed()

CustomSemantics.kt

import androidx.compose.ui.semantics.SemanticsPropertyKey
import androidx.compose.ui.semantics.SemanticsPropertyReceiver

val DrawableId = SemanticsPropertyKey<List<Int>>(
    name = "DrawableResId",
    mergePolicy = mergeSemantics()
)

var SemanticsPropertyReceiver.drawableId: Int
    get() = throwSemanticsGetNotSupported()
    set(value) = set(DrawableId, listOf(value))

val DrawableUrl = SemanticsPropertyKey<List<String>>(
    name = "DrawableUrl",
    mergePolicy = mergeSemantics()
)

var SemanticsPropertyReceiver.drawableUrl: String
    get() = throwSemanticsGetNotSupported()
    set(value) = set(DrawableUrl, listOf(value))

private fun <T> mergeSemantics(): (List<T>?, List<T>) -> List<T> {
    return { parentValue, childValue ->
        parentValue?.toMutableList()?.also { it.addAll(childValue) } ?: childValue
    }
}

private fun <T> throwSemanticsGetNotSupported(): T {
    throw UnsupportedOperationException(
        "You cannot retrieve a semantics property directly - " +
                "use one of the SemanticsConfiguration.getOr* methods instead"
    )
}

CustomSemanticsMatcher.kt

import androidx.annotation.DrawableRes
import androidx.compose.ui.semantics.SemanticsPropertyKey
import androidx.compose.ui.semantics.getOrNull
import androidx.compose.ui.test.SemanticsMatcher
import com.ignitetech.compose.utility.DrawableId
import com.ignitetech.compose.utility.DrawableUrl

fun hasDrawable(@DrawableRes id: Int) = matcher(DrawableId, id)

fun hasDrawable(url: String?) = matcher(DrawableUrl, url)

private fun <T> matcher(property: SemanticsPropertyKey<List<T>>, expected: T?): SemanticsMatcher {
    return SemanticsMatcher("${property.name} = [$expected]") {
        it.config.getOrNull(property)?.any { item -> item == expected } ?: false
    }
}