Add synchronization

Author: Daniel Jette

Ext/Compose/build.gradle

@@ -83,6 +83,7 @@ android {
         implementation "androidx.compose.ui:ui-tooling-preview:${versions.compose}"
         implementation "androidx.compose.ui:ui:${versions.compose}"
         implementation "androidx.lifecycle:lifecycle-runtime-ktx:${versions.androidx.lifecycleKtx}"
+        implementation "androidx.test.espresso:espresso-core:${versions.androidx.test.espresso}"
         implementation "androidx.test:rules:${versions.androidx.test.rules}"
         implementation "androidx.test:runner:${versions.androidx.test.runner}"
         implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8:${versions.kotlin}"

Ext/Compose/src/main/java/com/shopify/testify/ComposableScreenshotRule.kt

@@ -27,9 +27,12 @@ import android.app.Activity
 import android.graphics.Bitmap
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.platform.ComposeView
+import androidx.test.espresso.Espresso
 import com.shopify.testify.compose.R
 import com.shopify.testify.internal.disposeComposition
-import org.junit.Before
+import org.junit.Assert.assertTrue
+import java.util.concurrent.CountDownLatch
+import java.util.concurrent.TimeUnit
 
 /**
  * Helper extension of [ScreenshotRule] which simplifies testing [Composable] functions.
@@ -62,12 +65,17 @@ open class ComposableScreenshotRule(
      * Render the composable function after the activity has loaded.
      */
     override fun afterActivityLaunched() {
+        Espresso.onIdle()
+        val latch = CountDownLatch(1)
         activity.runOnUiThread {
             val composeView = activity.findViewById<ComposeView>(R.id.compose_container)
             composeView.setContent {
                 composeFunction()
+                latch.countDown()
             }
         }
+        assertTrue(latch.await(COMPOSE_TIMEOUT_SECONDS, TimeUnit.SECONDS))
+        Espresso.onIdle()
         super.afterActivityLaunched()
     }
 
@@ -86,4 +94,8 @@ open class ComposableScreenshotRule(
         composeFunction = composable
         return this
     }
+
+    companion object {
+        private const val COMPOSE_TIMEOUT_SECONDS: Long = 15
+    }
 }

Sample/src/androidTest/assets/screenshots/29-1080x2220@440dp-en_US/ComposableScreenshotTest_default.png

@@ -78,7 +78,7 @@ class ComposableScreenshotTest {
 
     @ScreenshotInstrumentation
     @Test
-    fun _default() {
+    fun paddedBoxes() {
         rule
             .setCompose {
                 PaddedBox(Color.Gray) {