feat: add screenshot testing to compose snippets

compose/snippets/build.gradle.kts

@@ -21,6 +21,7 @@ plugins {
     alias(libs.plugins.kotlin.parcelize)
     alias(libs.plugins.compose.compiler)
     alias(libs.plugins.kotlin.serialization)
+    alias(libs.plugins.screenshot)
 }
 
 kotlin {
@@ -30,6 +31,7 @@ kotlin {
 android {
     compileSdk = libs.versions.compileSdk.get().toInt()
     namespace = "com.example.compose.snippets"
+    experimentalProperties["android.experimental.enableScreenshotTest"] = true
 
     defaultConfig {
         applicationId = "com.example.compose.snippets"
@@ -181,4 +183,7 @@ dependencies {
 
     androidTestImplementation(libs.androidx.glance.testing)
     androidTestImplementation(libs.androidx.glance.appwidget.testing)
+
+    screenshotTestImplementation(libs.screenshot.validation.api)
+    screenshotTestImplementation(libs.androidx.ui.tooling)
 }

compose/snippets/src/androidTest/java/com/example/compose/snippets/adaptivelayouts/MyFeedTest.kt

@@ -0,0 +1,43 @@
+/*
+ * Copyright 2026 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.compose.snippets.adaptivelayouts
+
+import androidx.compose.ui.test.assertIsDisplayed
+import androidx.compose.ui.test.junit4.v2.createComposeRule
+import androidx.compose.ui.test.onNodeWithText
+import org.junit.Rule
+import org.junit.Test
+
+class MyFeedTest {
+
+    @get:Rule
+    val composeTestRule = createComposeRule()
+
+    @Test
+    fun myFeed_displaysItems() {
+        val names = listOf("Alice", "Bob", "Charlie")
+
+        composeTestRule.setContent {
+            MyFeed(names = names)
+        }
+
+        // Verify that all names in the feed are displayed
+        for (name in names) {
+            composeTestRule.onNodeWithText(name).assertIsDisplayed()
+        }
+    }
+}

compose/snippets/src/screenshotTest/java/com/example/compose/snippets/adaptivelayouts/MyFeedScreenShotTest.kt

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2026 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.compose.snippets.adaptivelayouts
+
+import android.content.res.Configuration
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.tooling.preview.Preview
+import androidx.compose.ui.tooling.preview.PreviewParameter
+import androidx.compose.ui.tooling.preview.PreviewParameterProvider
+import androidx.compose.ui.tooling.preview.Wallpapers
+import com.android.tools.screenshot.PreviewTest
+import com.example.compose.snippets.adaptivelayouts.MyFeed
+
+class SampleNamesProvider : PreviewParameterProvider<List<String>> {
+    override val values = sequenceOf(
+        listOf("User 1", "User 2", "User 3", "User 4", "User 5")
+    )
+}
+
+@PreviewTest
+@Preview
+@Composable
+fun MyFeedPreview(
+    @PreviewParameter(SampleNamesProvider::class) names: List<String>,
+) {
+    MyFeed(names)
+}

compose/snippets/src/screenshotTest/java/com/example/compose/snippets/layouts/grid/GridExampleTest.kt

@@ -0,0 +1,57 @@
+/*
+ * Copyright 2026 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.compose.snippets.layouts.grid
+
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.tooling.preview.Preview
+import com.android.tools.screenshot.PreviewTest
+
+
+@Preview
+@PreviewTest
+@Composable
+fun GridExamplePreviewTest() {
+    GridExample()
+}
+
+@Preview
+@PreviewTest
+@Composable
+fun SixCardsPreviewTest() {
+    SixCards()
+}
+
+@Preview
+@PreviewTest
+@Composable
+fun DefineGridPreviewTest() {
+    DefineGrid()
+}
+
+@Preview
+@PreviewTest
+@Composable
+fun DefineGridAndPlaceItemsPreviewTest() {
+    DefineGridAndPlaceItems()
+}
+
+@Preview
+@PreviewTest
+@Composable
+fun DefineExplicitAndImplicitGridTracksPreviewTest() {
+    DefineExplicitAndImplicitGridTracks()
+}

gradle.properties

@@ -27,3 +27,5 @@ android.enableR8.fullMode=true
 # Use an AndroidX snapshot build.
 # https://androidx.dev/snapshots/builds
 # snapshotVersion=14793336
+
+android.experimental.enableScreenshotTest=true

gradle/libs.versions.toml

@@ -123,6 +123,7 @@ compose-remote = "1.0.0-alpha11"
 glance-wear = "1.0.0-alpha10"
 remote-material3 = "1.0.0-alpha04"
 screenshotValidationApi = "0.0.1-alpha14"
+screenshot = "0.0.1-alpha15"
 
 [libraries]
 accompanist-adaptive = "com.google.accompanist:accompanist-adaptive:0.37.3"
@@ -309,6 +310,7 @@ androidx-compose-remote-tooling-preview = { module = "androidx.compose.remote:re
 glance-preview = { group = "androidx.glance", name = "glance-preview", version.ref = "androidx-glance-appwidget" }
 glance-appwidget-preview = { group = "androidx.glance", name = "glance-appwidget-preview", version.ref = "androidx-glance-appwidget" }
 screenshot-validation-api = { group = "com.android.tools.screenshot", name = "screenshot-validation-api", version.ref = "screenshotValidationApi" }
+androidx-ui-tooling = { group = "androidx.compose.ui", name = "ui-tooling"}
 
 [plugins]
 android-application = { id = "com.android.application", version.ref = "androidGradlePlugin" }
@@ -324,5 +326,6 @@ kotlin-parcelize = { id = "org.jetbrains.kotlin.plugin.parcelize", version.ref =
 kotlin-serialization = { id = "org.jetbrains.kotlin.plugin.serialization", version.ref = "kotlin" }
 ksp = { id = "com.google.devtools.ksp", version.ref = "ksp" }
 roborazzi = { id = "io.github.takahirom.roborazzi", version.ref = "roborazzi" }
+screenshot = { id = "com.android.compose.screenshot", version.ref = "screenshot"}
 spotless = { id = "com.diffplug.spotless", version.ref = "spotless" }
 version-catalog-update = { id = "nl.littlerobots.version-catalog-update", version.ref = "version-catalog-update" }