Has anyone encountered an issue when UI testing compose - where applying multiple `testTag` to the s...

# compose-android

[Tim Malseed]

Has anyone encountered an issue when UI testing compose - where applying multiple testTag to the same modifier means that onNodeWithTag fails for subsequent test tags?

e.g.

fun RootScreen() {
    SomeScreen(modifier = Modifier.semantics { testTag = "tag_a" }
}

fun SomeScreen(modifier: Modifier) {
    Scaffold (modifier = modifier.semantics { testTag = "test_b" }) { ...
}

A test with onNodeWithTag("test_b") fails. But if I remove tag_a, it succeeds.

[Tim Malseed]

It makes no difference whether I useUnmergedTree or not

[Tim Malseed]

Looking at the SemanticsProperties code:

val TestTag = SemanticsPropertyKey<String>(
    name = "TestTag",
    mergePolicy = { parentValue, _ ->
        // Never merge TestTags, to avoid leaking internal test tags to parents.
        parentValue
    }
)

It’s interesting, the ‘merge policy’ seems to say ‘only ever use the parent value’
I’m going to guess that means if there’s a conflict when adding a tag, then the tag is ignored and the original tag is retained