feat(compose): Add Compose testing common patterns snippet

Author: cartland

compose/snippets/src/androidTest/java/com/android/example/compose/testing/CommonPatternsSample.kt

@@ -0,0 +1,62 @@
+/*
+ * Copyright 2025 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.android.example.compose.testing
+
+import androidx.activity.ComponentActivity
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.test.junit4.createAndroidComposeRule
+import androidx.compose.ui.test.onNodeWithText
+import androidx.compose.ui.test.performClick
+import org.junit.Rule
+import org.junit.Test
+import com.example.compose.snippets.R
+
+class CommonPatternsSample {
+
+    @get:Rule
+    val composeTestRule = createAndroidComposeRule<ComponentActivity>()
+
+    @Test
+    fun myTest() {
+        // [START android_snippets_compose_testing_common_patterns]
+        // Start the app
+        composeTestRule.setContent {
+            MyAppTheme {
+                MainScreen(uiState = exampleUiState, /*...*/)
+            }
+        }
+        val continueLabel = composeTestRule.activity.getString(R.string.next)
+        composeTestRule.onNodeWithText(continueLabel).performClick()
+        // [END android_snippets_compose_testing_common_patterns]
+    }
+}
+
+@Composable
+fun MyAppTheme(content: @Composable () -> Unit) {
+    content()
+}
+
+@Composable
+fun MainScreen(uiState: ExampleUiState) {
+    Text(text = "Hello ${uiState.name}")
+    Text(text = "Next")
+}
+
+data class ExampleUiState(val name: String)
+
+val exampleUiState = ExampleUiState("world")

compose/snippets/src/main/res/values/strings.xml

@@ -16,6 +16,7 @@
   -->
 <resources>
     <string name="app_name">snippets</string>
+    <string name="next" translatable="false">Next</string>
     <string name="dog_content_description">Golden Retriever in fall leaves</string>
     <string name="shopping_cart_content_desc">Shopping cart</string>
     <string name="bus_content_description">Bus</string>