Getting Started with Compose UI Testing using Dagger Hilt

Why write a UI test?

There are many reasons to write UI tests. Here are a few key ones:

• Ensures correct UI behavior.
• Reduces manual testing.
• Detects bugs early.
• Supports complex interactions.
• Prevents regressions.

Setup Dagger Hilt for test

Add dependencies

dependencies {
  
    androidTestImplementation("com.google.dagger:hilt-android-testing:$compose_version")
    kaptAndroidTest("com.google.dagger:hilt-android-compiler:$compose_version")
  
}

Create HiltTestRunner class in your androidTest package

class HiltTestRunner: AndroidJUnitRunner() {

    override fun newApplication(
        cl: ClassLoader?,
        className: String?,
        context: Context?
    ): Application {
        return super.newApplication(cl, HiltTestApplication::class.java.name, context)
    }
}

In your app’s build.gradle

android {

    defaultConfig {
        //replace your package name here
        testInstrumentationRunner = "com.mypackage.newapp.HiltTestRunner"
    }
}

Writing simple UI Test

I already have a sample app which looks like this\

Now to start writing UI test, create a test class in your androidTest package

@HiltAndroidTest
class AddTaskTest {

    @get:Rule(order = 1)
    var hiltRule = HiltAndroidRule(this)
    @get:Rule(order = 2)
    var rule = createAndroidComposeRule<MainActivity>()
}

We need to define two rules: HiltAndroidRule, which is required to create the Dagger component, and createAndroidComposeRule() , which helps us launch a specific activity that already has a setContentfunction defined.

Now let’s write our test function.

@Test
    fun clickPlusButton_popABottomSheet() {

        rule.onNodeWithContentDescription("Add")
            .performClick()
        rule.onNodeWithText("Task Name")
            .assertIsDisplayed()
        rule.onNodeWithTag("TextFieldTaskName")
            .performClick()

        rule.onNodeWithTag("TextFieldTaskName")
            .performTextInput("Write a UI Test")

        rule.onNodeWithContentDescription("Save Task")
            .performClick()
        rule.onNodeWithText("Write a UI Test")
            .assertIsDisplayed()
    }

I am performing the following steps:

• Clicking on a node with the content description Add.
• Verifying if the bottom sheet is launched by checking for a component in the bottom sheet with the text hint Task Name.
• Clicking on the TextField with the tag TextFieldTaskName and ensuring it is focused.
• Entering the input Write a UI Test.
• Clicking on a button with the content description Save Task.
• Verifying if that task appears on the main screen using assertIsDisplayed().

That’s it! Congratulations, you’ve just written your first UI test.