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finding-nodes-by-tag-text-content

Testing & quality

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Updated 10-16 02:18

About this skill

Finding Nodes by Tag, Text, or Content Description — Tag From Production, Find by Tag From Tests

Every Compose UI test starts by locating a semantics node. This skill picks the right finder, reasons about the count contract, and decides when to flip useUnmergedTree. Use it whenever the developer is staring at a "Reason: Expected exactly '1' node but could not find any node that satisfies …" error.

When to use this skill

  • The developer reports "no node matched" / "multiple nodes matched" / "tag not found" / "ambiguous match" from SemanticsNodeInteraction.
  • The developer asks how to locate a Button, Text, Icon, IconButton, Switch, or any other composable inside a test.
  • The developer mentions onNodeWithTag, onNodeWithText, onNodeWithContentDescription, onAllNodesWith*, or onRoot.
  • A test passes locally but is brittle to copy edits or i18n rotation of the UI strings.
  • The developer asks about useUnmergedTree, the merged tree, or "why does my inner Text not exist".

When NOT to use this skill

  • The right node is found but assertions fail — see ../../assertions/asserting-node-state-and-text/SKILL.md (state) or ../../assertions/asserting-bounds-and-dimensions/SKILL.md (geometry).
  • The finder returns one node but custom predicates are needed — see ../composing-semantics-matchers/SKILL.md.
  • The right node exists but only as a child/sibling/descendant — see ../traversing-the-semantics-tree/SKILL.md.
  • The semantics tree itself needs inspection — see ../../debug/printing-the-semantics-tree/SKILL.md.

Prerequisites

  • androidx.compose.ui:ui-test-junit4 (or v2) wired up. See ../../setup/configuring-test-dependencies/SKILL.md if createComposeRule is unresolved.
  • A ComposeTestRule or ComposeUiTest is in scope. See ../../setup/choosing-test-rule-vs-runtest/SKILL.md.
  • The composable under test calls setContent { … } before the finder runs. Finders are lazy and re-evaluate on every operation.

Workflow

  • 1. Default to onNodeWithTag(SomeTag). Add a Modifier.testTag(SomeTag) in the production source under a const val SomeTag = "Some". Tests find by tag, not by text. Skydoves hot take #1: in androidx/material3 itself, onNodeWithTag outnumbers onNodeWithText roughly 4:1 (1825 vs 424) and onNodeWithContentDescription 40:1 (1825 vs 46). Text finders churn with copy edits and break on locale rotation.

  • 2. Pick the finder by signal type. Mapping (all from commonMain/.../Finders.kt):

    Need to match by … Finder File:line
    Modifier.testTag("…") onNodeWithTag(testTag, useUnmergedTree=false) Finders.kt:31-35
    Visible/editable/input text onNodeWithText(text, substring=false, ignoreCase=false, useUnmergedTree=false) Finders.kt:110-116
    Accessibility content description onNodeWithContentDescription(label, substring=false, ignoreCase=false, useUnmergedTree=false) Finders.kt:66-73
    Custom predicate onNode(matcher, useUnmergedTree=false) from SemanticsNodeInteractionsProvider SemanticsNodeInteractionsProvider.kt
    Whole tree onRoot(useUnmergedTree=false) Finders.kt:150-153

    Each onNodeWith* is a thin @CheckResult wrapper over onNode(hasTestTag(...))/onNode(hasText(...))/onNode(hasContentDescription(...)). The behavior is identical to the matcher form.

  • 3. Respect the count contract. SemanticsNodeInteraction (single) throws AssertionError when fetched against 0 or >1 matching nodes (SemanticsNodeInteraction.kt:150-191). SemanticsNodeInteractionCollection (plural) never throws on 0 — it returns an empty collection that assertCountEquals(0) will accept (Assertions.kt:276-292). Pick the variant that matches the expected cardinality.

  • 4. Flip useUnmergedTree = true only for inner elements. The merged tree collapses descendants whose semantics roll up into the parent — Text and Icon inside a Button appear as one node. To target the inner Text, pass useUnmergedTree = true. The flag is sticky: once a finder is created with useUnmergedTree = true, every subsequent onChild/onParent/filter keeps it on (SemanticsNodeInteraction.kt:42-49). Skydoves hot take #2: default to merged; flip only when targeting composition detail.

  • 5. Read the auto-suggested unmerged hint on count mismatch. When a finder targets the merged tree and finds zero, the framework re-runs the same query against the unmerged tree and embeds the matches in the error message (SemanticsNodeInteraction.kt:184-205, getNodesInUnmergedTree). If the error shows nodes that "would have matched" with useUnmergedTree = true, flip the flag.

  • 6. For substring or case-insensitive text matches, pass the boolean flags explicitly. onNodeWithText("Sub", substring = true) matches "Submit" and "Subscribe". Combine with onAllNodesWithText plus assertCountEquals to express intent (see Pattern: ambiguous text below).

Patterns

Pattern: tag from production, find by tag from tests

// WRONG
@Test
fun submit_isEnabled_afterFormFilled() {
    rule.setContent { CheckoutScreen() }
    rule.onNodeWithText("Place order").assertIsEnabled()
}
// WRONG because: the button label changes with copy edits, and the test breaks the moment QA
// asks for "Buy now". Also fails under any locale that is not the test default.

// RIGHT
// production: ui/checkout/CheckoutScreen.kt
const val PlaceOrderButtonTag = "CheckoutScreen.PlaceOrderButton"

@Composable
fun CheckoutScreen() {
    Button(modifier = Modifier.testTag(PlaceOrderButtonTag), onClick = { /* … */ }) {
        Text(stringResource(R.string.place_order))
    }
}

// test:
@Test
fun submit_isEnabled_afterFormFilled() {
    rule.setContent { CheckoutScreen() }
    rule.onNodeWithTag(PlaceOrderButtonTag).assertIsEnabled()
}

Pattern: collection finder when the count is the assertion

// WRONG
@Test
fun greeting_appearsTwice() {
    rule.setContent { GreetingList(listOf("Hello", "Hello")) }
    // Returns the first match silently; never proves "twice".
    rule.onNodeWithText("Hello").assertIsDisplayed()
}
// WRONG because: onNode* throws on >1 matches; if the duplicate count drifts to 1 the test
// passes for the wrong reason, and if it drifts to 3 the test fails with an opaque count error.

// RIGHT
@Test
fun greeting_appearsTwice() {
    rule.setContent { GreetingList(listOf("Hello", "Hello")) }
    rule.onAllNodesWithText("Hello").assertCountEquals(2)
}

Pattern: matching an inner Text inside a Button (merge collapse)

// WRONG
@Test
fun button_text_isShown() {
    rule.setContent {
        Button(onClick = {}, modifier = Modifier.testTag("submit")) {
            Text("Submit", modifier = Modifier.testTag("submitLabel"))
        }
    }
    rule.onNodeWithTag("submitLabel").assertIsDisplayed()
}
// WRONG because: in the merged tree the Text is rolled into the Button. The finder sees zero
// nodes and the auto-attached unmerged hint will surface in the error message — flip the flag.

// RIGHT
@Test
fun button_text_isShown() {
    rule.setContent { /* same content */ }
    rule.onNodeWithTag("submitLabel", useUnmergedTree = true).assertIsDisplayed()
}

Pattern: substring/ignoreCase for partial copy

// WRONG
rule.onNodeWithText("hello").assertIsDisplayed()
// WRONG because: matches only the exact string. UI showing "Hello, world" or "HELLO" produces
// a "no node matched" error.

// RIGHT — when intent really is "contains 'Hello'":
rule.onNodeWithText("Hello", substring = true, ignoreCase = true).assertIsDisplayed()

// RIGHTER — prefer a tag and assert the text once:
rule.onNodeWithTag(GreetingTag).assertTextContains("Hello", substring = true, ignoreCase = true)

Pattern: content description for icon-only controls

// production:
IconButton(onClick = onShare, modifier = Modifier.testTag(ShareButtonTag)) {
    Icon(Icons.Default.Share, contentDescription = stringResource(R.string.share))
}

// test:
rule.onNodeWithTag(ShareButtonTag).assertIsDisplayed()                  // PREFERRED
rule.onNodeWithContentDescription("Share").assertIsDisplayed()          // acceptable for accessibility-focused tests

onNodeWithContentDescription defaults to merged-tree exact match, so the merged Icon's content description rolls up to the parent IconButton. To match a specific Icon's description in a button that contains many icons, flip useUnmergedTree = true.

Pattern: onRoot() as the screenshot/print starting point

rule.onRoot().printToLog("tree")                  // dump merged
rule.onRoot(useUnmergedTree = true).printToLog("unmerged")

See ../../debug/printing-the-semantics-tree/SKILL.md for printToLog / printToString depth controls.

Mandatory rules

  • MUST prefer onNodeWithTag over onNodeWithText and onNodeWithContentDescription. Skydoves hot take #1.
  • MUST put the Modifier.testTag(...) in production code under a constant. MUST NOT redefine the same string literal in both the production source and the test.
  • MUST default to useUnmergedTree = false. Flip to true only when targeting an inner element collapsed by merge or verifying composition detail. Skydoves hot take #2.
  • MUST use onAllNodesWith* + assertCountEquals when the count itself is part of the test contract. MUST NOT rely on onNodeWith* to imply "exactly one" by side effect.
  • MUST NOT chain finders inside a single statement past the point of clarity (e.g. onNode(...).onChild().onChildAt(2).onChild()). Add a tag instead — see ../traversing-the-semantics-tree/SKILL.md.
  • PREFERRED: when a count-mismatch error shows unmerged-tree matches, flip useUnmergedTree = true rather than rewriting the matcher.

Verification

  • Every finder in the test file uses onNodeWithTag unless the assertion is explicitly about user-visible text or accessibility content description.
  • Every test tag is defined as a const val in the production source, not inlined in the test.
  • useUnmergedTree = true appears only at sites that target an inner element of a merged composable (Button, IconButton, ListItem, etc.).
  • No raw string-literal text comparison appears where a tag would do.
  • ./gradlew :app:connectedDebugAndroidTest (device) or :app:testDebugUnitTest (Robolectric host) passes locally.
  • No "Reason: Expected exactly '1' node" errors remain.

References