Fix experimental API warnings in Compose UI tests

Add @OptIn(ExperimentalTestApi::class) annotation to all test classes
to suppress "This testing API is experimental and is likely to be changed
or removed entirely" warnings.

Changes:
- Add @OptIn(ExperimentalTestApi::class) to ComposeMultiplatformUiTests
- Add @OptIn(ExperimentalTestApi::class) to ISSPositionUiTests
- Add @OptIn(ExperimentalTestApi::class) to TestTagExampleTests
- Add @OptIn(ExperimentalTestApi::class) to ViewModelUiTests
- Update README.md with documentation about the opt-in requirement
- Update all code examples in README to include the annotation
- Add note explaining why the annotation is needed

The annotation is required because the Compose Multiplatform UI testing
framework (runComposeUiTest) is currently experimental. This is standard
practice when using experimental APIs and does not affect test functionality.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: claude

common/src/commonTest/kotlin/README.md

@@ -56,6 +56,7 @@ class MyTest {
 
 ### Multiplatform Tests (common module)
 ```kotlin
+@OptIn(ExperimentalTestApi::class)
 class MyTest {
     @Test
     fun myTest() = runComposeUiTest {
@@ -65,6 +66,8 @@ class MyTest {
 }
 ```
 
+**Note**: The `@OptIn(ExperimentalTestApi::class)` annotation is required because the Compose Multiplatform UI testing API is currently experimental. Add this annotation to your test classes to suppress experimental API warnings.
+
 ## Running the Tests
 
 ### Run all common tests
@@ -97,27 +100,34 @@ class MyTest {
 All tests follow this pattern:
 
 ```kotlin
-@Test
-fun testName() = runComposeUiTest {
-    // 1. Setup (if needed)
-    val viewModel = MyViewModel(fakeRepository)
-
-    // 2. Set content
-    setContent {
-        MaterialTheme {
-            MyComposable(viewModel)
+@OptIn(ExperimentalTestApi::class)
+class MyUiTests {
+    @Test
+    fun testName() = runComposeUiTest {
+        // 1. Setup (if needed)
+        val viewModel = MyViewModel(fakeRepository)
+
+        // 2. Set content
+        setContent {
+            MaterialTheme {
+                MyComposable(viewModel)
+            }
         }
-    }
 
-    // 3. Advance time (for async operations)
-    testDispatcher.scheduler.advanceUntilIdle()
-    waitForIdle()
+        // 3. Advance time (for async operations)
+        testDispatcher.scheduler.advanceUntilIdle()
+        waitForIdle()
 
-    // 4. Assert
-    onNodeWithText("Expected Text").assertIsDisplayed()
+        // 4. Assert
+        onNodeWithText("Expected Text").assertIsDisplayed()
+    }
 }
 ```
 
+### Important: Experimental API
+
+The Compose Multiplatform UI testing framework is currently experimental. You must add the `@OptIn(ExperimentalTestApi::class)` annotation to your test classes to use `runComposeUiTest` and suppress experimental API warnings.
+
 ## Common Test Assertions
 
 ### Existence
@@ -288,30 +298,43 @@ val viewModel = MyViewModel(fakeRepository)
 
 ### Testing CoordinateDisplay
 ```kotlin
-@Test
-fun testCoordinateDisplay() = runComposeUiTest {
-    setContent {
-        CoordinateDisplay(label = "Latitude", value = "53.27")
+@OptIn(ExperimentalTestApi::class)
+class CoordinateDisplayTests {
+    @Test
+    fun testCoordinateDisplay() = runComposeUiTest {
+        setContent {
+            CoordinateDisplay(label = "Latitude", value = "53.27")
+        }
+        onNodeWithText("Latitude").assertIsDisplayed()
+        onNodeWithText("53.27").assertIsDisplayed()
     }
-    onNodeWithText("Latitude").assertIsDisplayed()
-    onNodeWithText("53.27").assertIsDisplayed()
 }
 ```
 
 ### Testing with ViewModel
 ```kotlin
-@Test
-fun testWithViewModel() = runComposeUiTest {
-    val viewModel = ISSPositionViewModel(fakeRepository)
+@OptIn(ExperimentalTestApi::class)
+class ViewModelIntegrationTests {
+    private val testDispatcher = StandardTestDispatcher()
 
-    setContent {
-        ISSPositionContent(viewModel)
+    @BeforeTest
+    fun setup() {
+        Dispatchers.setMain(testDispatcher)
     }
 
-    testDispatcher.scheduler.advanceUntilIdle()
-    waitForIdle()
+    @Test
+    fun testWithViewModel() = runComposeUiTest {
+        val viewModel = ISSPositionViewModel(fakeRepository)
+
+        setContent {
+            ISSPositionContent(viewModel)
+        }
 
-    onNodeWithText("53.2743394").assertIsDisplayed()
+        testDispatcher.scheduler.advanceUntilIdle()
+        waitForIdle()
+
+        onNodeWithText("53.2743394").assertIsDisplayed()
+    }
 }
 ```
 
@@ -324,8 +347,9 @@ fun testWithViewModel() = runComposeUiTest {
 ## Contributing
 
 When adding new UI tests:
-1. Follow the existing naming conventions
-2. Add test tags to new composables
-3. Create test composables for complex scenarios
-4. Document any platform-specific limitations
-5. Keep tests fast and focused
+1. Add `@OptIn(ExperimentalTestApi::class)` to your test class
+2. Follow the existing naming conventions (e.g., `*UiTests.kt`)
+3. Add test tags to new composables
+4. Create test composables for complex scenarios
+5. Document any platform-specific limitations
+6. Keep tests fast and focused

common/src/commonTest/kotlin/com/surrus/peopleinspace/ui/ComposeMultiplatformUiTests.kt

@@ -16,6 +16,7 @@ import kotlin.test.Test
  * - Works with kotlin.test instead of JUnit
  * - Can be executed on multiple platforms
  */
+@OptIn(ExperimentalTestApi::class)
 class ComposeMultiplatformUiTests {
 
     @Test

common/src/commonTest/kotlin/com/surrus/peopleinspace/ui/ISSPositionUiTests.kt

@@ -12,6 +12,7 @@ import kotlin.test.Test
  * These tests demonstrate testing Compose Multiplatform UI components
  * with realistic data from a fake repository.
  */
+@OptIn(ExperimentalTestApi::class)
 class ISSPositionUiTests {
 
     private val repository = PeopleInSpaceRepositoryFake()

common/src/commonTest/kotlin/com/surrus/peopleinspace/ui/TestTagExampleTests.kt

@@ -20,6 +20,7 @@ import kotlin.test.Test
  * 3. Apply test tags to key interactive elements and containers
  * 4. Use test tags over text matching for better test stability
  */
+@OptIn(ExperimentalTestApi::class)
 class TestTagExampleTests {
 
     companion object {

common/src/commonTest/kotlin/com/surrus/peopleinspace/viewmodel/ViewModelUiTests.kt

@@ -24,6 +24,7 @@ import kotlin.test.Test
  * These tests show how to test Compose UI components that interact with ViewModels,
  * using a fake repository to provide test data.
  */
+@OptIn(ExperimentalTestApi::class)
 class ViewModelUiTests {
 
     private val testDispatcher = StandardTestDispatcher()