ExampleInstrumentedTest.kt

package io.github.kevinah95.unit01.l02_repaso

import androidx.compose.ui.test.assertIsDisplayed
import androidx.compose.ui.test.hasTestTag
import androidx.compose.ui.test.junit4.createAndroidComposeRule
import androidx.test.platform.app.InstrumentationRegistry
import androidx.test.ext.junit.runners.AndroidJUnit4

import org.junit.Test
import org.junit.runner.RunWith

import org.junit.Assert.*
import org.junit.Rule

/**
 * Instrumented test, which will execute on an Android device.
 *
 * See [testing documentation](http://d.android.com/tools/testing).
 */
@RunWith(AndroidJUnit4::class)
class ExampleInstrumentedTest {

    @get:Rule val composeTestRule = createAndroidComposeRule<MainActivity>()

    @Test
    fun testGreeting() {
        composeTestRule.onNode(hasTestTag("greeting_text")).assertIsDisplayed()
    }
}

ExampleScreenshotTest.kt

package io.github.kevinah95.unit01.l02_repaso

import androidx.compose.runtime.Composable
import androidx.compose.ui.tooling.preview.Preview
import io.github.kevinah95.unit01.l02_repaso.ui.theme.L02repasoTheme

class ExampleScreenshotTest {

    @Preview
    @Composable
    fun GreetingPreview(){
        L02repasoTheme {
            GreetingImage(message = "Happy Birthday Kevin!", from = "— From Jenni")
        }
    }
}