Error during BDD-Test for Android: java.lang.IllegalStateException: No compose hierarchies found in the app

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05-10-2024

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Debugging "java.lang.IllegalStateException: No compose hierarchies found in the app" in Android BDD Tests

The Problem:

You're trying to run your Behavior-Driven Development (BDD) tests for your Android application, but you're encountering the frustrating "java.lang.IllegalStateException: No compose hierarchies found in the app" error. This means your test framework can't find any Jetpack Compose UI elements to interact with.

Scenario:

Imagine you're writing an Android app using Jetpack Compose and want to automate your testing process with BDD frameworks like Cucumber or Spek. You set up your tests, using a framework like androidx.compose.ui.test.junit4.AndroidComposeTestRule, but when you run them, you get hit with the "No compose hierarchies found" error.

Original Code Example (Using Cucumber):

import androidx.compose.ui.test.junit4.AndroidComposeTestRule
import io.cucumber.java.en.Given
import io.cucumber.java.en.Then
import io.cucumber.java.en.When

class MyFeatureSteps {
    @AndroidComposeTestRule
    lateinit var composeTestRule: AndroidComposeTestRule

    @Given("the app is launched")
    fun launchApp() {
        // Launch the app and wait for it to be ready 
    }

    @When("I click on the login button")
    fun clickLoginButton() {
        composeTestRule.onNodeWithText("Login").performClick()
    }

    @Then("the login screen is displayed")
    fun verifyLoginScreen() {
        composeTestRule.onNodeWithText("Username").assertIsDisplayed()
    }
}

Understanding the Error:

The "No compose hierarchies found" error typically stems from a mismatch between your test code and the actual state of the app under test. There are several common causes:

1. Incorrect Test Rule Initialization:

   • Ensure you're using the correct AndroidComposeTestRule or ComposeTestRule instance for your specific setup.
   • You need to use @AndroidComposeTestRule annotation or initialize it within your test class.

2. Compose UI Hierarchy Not Available:

   • The error can occur if the test tries to interact with the UI before the Compose UI hierarchy is fully rendered.
   • Ensure that the UI element you're trying to access has been created and is part of the visible UI.

3. Incorrect Selector:

   • If the test uses onNodeWithText() or other selectors to identify an element, the selector might be incorrect or target an element that isn't present in the UI.

4. Integration Issues with Testing Libraries:

   • Ensure you're using compatible versions of your testing libraries and Jetpack Compose. Check for compatibility updates or known issues.

Debugging and Solutions:

1. Verify Launch Activity:

   • Make sure the activity that hosts your Compose UI is set as the launch activity in your AndroidManifest.xml.

2. Use waitForIdle:

   • Use the composeTestRule.waitForIdle() method to ensure the Compose UI has finished rendering before interacting with any elements.

3. Use waitForCondition:

   • You can wait for specific conditions within the UI to be met using composeTestRule.waitForCondition() method. This helps ensure your test code interacts with the UI at the right moment.

4. Check the Selector:

   • Carefully check that the selector (e.g., onNodeWithText()) correctly identifies the desired element in your Compose UI.
   • Use a debugger to inspect the UI hierarchy and validate the selector.

5. Update Dependencies:

   • Ensure that your testing dependencies are updated to the latest compatible versions with Jetpack Compose.

Example Fix (Using waitForIdle):

import androidx.compose.ui.test.junit4.AndroidComposeTestRule
import io.cucumber.java.en.Given
import io.cucumber.java.en.Then
import io.cucumber.java.en.When

class MyFeatureSteps {
    @AndroidComposeTestRule
    lateinit var composeTestRule: AndroidComposeTestRule

    @Given("the app is launched")
    fun launchApp() {
        // Launch the app and wait for it to be ready 
        composeTestRule.waitForIdle()
    }

    @When("I click on the login button")
    fun clickLoginButton() {
        composeTestRule.onNodeWithText("Login").performClick()
    }

    @Then("the login screen is displayed")
    fun verifyLoginScreen() {
        composeTestRule.waitForIdle()
        composeTestRule.onNodeWithText("Username").assertIsDisplayed()
    }
}

Additional Tips:

• Use composeTestRule.printToLog("UI Hierarchy") to print the current state of your Compose UI to your test logs.
• Use composeTestRule.onRoot().printToLog("Root UI Hierarchy") to print the root of the UI hierarchy.
• Remember to consult the official Jetpack Compose testing documentation for more in-depth guidance: https://developer.android.com/jetpack/compose/testing

Key Takeaways:

• The "No compose hierarchies found" error usually indicates that your test code is trying to access a Compose UI element before it's fully rendered.
• Carefully check your selectors, ensure the UI is fully rendered, and utilize tools like waitForIdle to avoid race conditions in your tests.

By following these steps and understanding the common causes of the error, you can effectively debug and fix this issue in your BDD tests for Android applications built with Jetpack Compose.