Compose Testing

Compose UI tests verify observable behavior through the semantics tree. They do not inspect composable functions directly. For the broader test strategy and View-based UI tests, see Android UI Testing.

Compose UI tests

A test uses createComposeRule() when it supplies its own content, or createAndroidComposeRule<Activity>() when the scenario needs an Activity. After setContent, find a semantics node, act on it, and assert the resulting UI state:

var saved = false
composeTestRule.setContent { EditorScreen(onSave = { saved = true }) }
composeTestRule.onNodeWithText("Save").performClick()
assertThat(saved).isTrue()

Prefer user-facing semantics such as text, role, selected state, or content description. Use a testTag for a stable selector when those properties are ambiguous or localized:

Modifier.testTag("save_button")

composeTestRule
    .onNodeWithTag("save_button")
    .performClick()

Actions and assertions normally wait for Compose to become idle. mainClock controls Compose recomposition and animations, but not every Android draw pass or external asynchronous operation. Use controllable fakes for external work; if necessary, wait for an observable condition with a bounded waitUntil or register an idling resource. Control the clock explicitly when testing animation progress.

Test the behavior a user can observe: enabled state, selection, loading/error/content, and callbacks or navigation outcomes. Avoid assertions about private state or a particular composable tree shape.

Semantics

Semantics describe the meaning of UI nodes for accessibility, testing, and tooling. Compose tests query semantics properties, not View IDs. Many built-in components provide useful properties automatically.

Modifier.semantics { ... } adds properties. Modifier.clearAndSetSemantics { ... } replaces the semantics exposed by a subtree: use it only when the combined control still has the label, role, state, and actions users need. A testTag alone is not an accessibility label.

Tests use the merged tree by default. If a child cannot be found, inspect the tree with onRoot().printToLog("ComposeTest"); use useUnmergedTree = true only when the child is intentionally tested separately. Prefer to interact with the parent control when it represents one user action.

Sources: Compose testing, Testing APIs, Test synchronization.