Feature request for improved waitUntil APIs.

Currently, ComposeTestRule's waitUntil function takes a condition lambda that produces a boolean.

This can be used to very effectively and easily synchronize a test with a UI by adding statements such as:

composeTestRule.waitUntil {
    composeTestRule
        .onAllNodesWithText("Welcome")
        .fetchSemanticsNodes().size == 1
}

Making this functionality generic to accept any matcher and any count of nodes would be easy with:


fun ComposeContentTestRule.waitUntilNodeCount(
    matcher: SemanticsMatcher,
    count: Int,
    timeoutMillis: Long = 1_000L
) {
    this.waitUntil(timeoutMillis) {
        this.onAllNodes(matcher).fetchSemanticsNodes().size == count
    }
}

Plus some sugar:

fun ComposeContentTestRule.waitUntilExists(
    matcher: SemanticsMatcher,
    timeoutMillis: Long = 1_000L
) {
    return this.waitUntilNodeCount(matcher, 1, timeoutMillis)
}

fun ComposeContentTestRule.waitUntilDoesNotExist(
    matcher: SemanticsMatcher,
    timeoutMillis: Long = 1_000L
) {
    return this.waitUntilNodeCount(matcher, 0, timeoutMillis)
}

Usage:

composeTestRule.waitUntilExists(hasText("Continue"))

More details and options in (internal doc): go/compose-test-waituntil-proposal