Add tests for DeviceInfoModule.getWindowDisplayMetrics edge-to-edge branches (facebook#56632)

Summary:
This PR adds two focused unit tests for `DeviceInfoModule.getWindowDisplayMetrics()` that attach a mocked `Activity`, swap in a fake `WindowMetricsCalculator` via `WindowMetricsCalculator.overrideDecorator()` and verify both branches of `isEdgeToEdgeFeatureFlagOn`:

- edge-to-edge on -> `WindowMetrics.bounds` are used directly.
- edge-to-edge off -> bounds minus `systemBars | displayCutout` insets.

To make this testable without reflection or `SuppressLint("RestrictedApi")` outside the production code, three small visibility tweaks:

- `DeviceInfoModule.getWindowDisplayMetrics()` and `getDisplayMetricsWritableMap()`: `private` → `internal` + `VisibleForTesting`
- `WindowUtilKt.isEdgeToEdgeFeatureFlagOn` setter: `private set` → `VisibleForTesting internal set`

## Changelog:

[INTERNAL] [ADDED] - Add unit tests for `DeviceInfoModule.getWindowDisplayMetrics` covering both edge-to-edge branches

Pull Request resolved: facebook#56632

Test Plan:
```
./gradlew :packages:react-native:ReactAndroid:testDebugUnitTest \
  --tests com.facebook.react.modules.deviceinfo.DeviceInfoModuleTest
```

Reviewed By: javache

Differential Revision: D102801090

Pulled By: alanleedev

fbshipit-source-id: 5e103404ef822d782c87117d77916221c512eaa2

Author: zoontek

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/modules/deviceinfo/DeviceInfoModule.kt

@@ -8,6 +8,7 @@
 package com.facebook.react.modules.deviceinfo
 
 import android.util.DisplayMetrics
+import androidx.annotation.VisibleForTesting
 import androidx.core.view.ViewCompat
 import androidx.core.view.WindowInsetsCompat
 import androidx.window.layout.WindowMetricsCalculator
@@ -36,7 +37,8 @@ internal class DeviceInfoModule(reactContext: ReactApplicationContext) :
     reactContext.addLifecycleEventListener(this)
   }
 
-  private fun getWindowDisplayMetrics(): DisplayMetrics {
+  @VisibleForTesting
+  internal fun getWindowDisplayMetrics(): DisplayMetrics {
     val windowDisplayMetrics = DisplayMetrics()
     windowDisplayMetrics.setTo(reactApplicationContext.resources.displayMetrics)
 
@@ -64,7 +66,8 @@ internal class DeviceInfoModule(reactContext: ReactApplicationContext) :
     return windowDisplayMetrics
   }
 
-  fun getDisplayMetricsWritableMap(): WritableMap =
+  @VisibleForTesting
+  internal fun getDisplayMetricsWritableMap(): WritableMap =
       WritableNativeMap().apply {
         putMap(
             "windowPhysicalPixels",

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/views/view/WindowUtil.kt

@@ -14,6 +14,7 @@ import android.view.View
 import android.view.Window
 import android.view.WindowInsetsController
 import android.view.WindowManager
+import androidx.annotation.VisibleForTesting
 import androidx.core.view.ViewCompat
 import androidx.core.view.WindowCompat
 import androidx.core.view.WindowInsetsCompat
@@ -35,7 +36,7 @@ internal val DarkNavigationBarColor = Color.argb(0x80, 0x1b, 0x1b, 0x1b)
  * as enabled elsewhere in the application.
  */
 public var isEdgeToEdgeFeatureFlagOn: Boolean = false
-  private set
+  @VisibleForTesting internal set
 
 public fun setEdgeToEdgeFeatureFlagOn() {
   isEdgeToEdgeFeatureFlagOn = true

packages/react-native/ReactAndroid/src/test/java/com/facebook/react/modules/deviceinfo/DeviceInfoModuleTest.kt

@@ -9,14 +9,25 @@
 
 package com.facebook.react.modules.deviceinfo
 
+import android.app.Activity
+import android.graphics.Rect
 import android.util.DisplayMetrics
+import android.view.View
+import android.view.Window
+import androidx.core.graphics.Insets
+import androidx.core.view.ViewCompat
+import androidx.core.view.WindowInsetsCompat
+import androidx.window.layout.WindowMetrics
+import androidx.window.layout.WindowMetricsCalculator
+import androidx.window.layout.WindowMetricsCalculatorDecorator
 import com.facebook.react.bridge.BridgeReactContext
 import com.facebook.react.bridge.JavaOnlyMap
 import com.facebook.react.bridge.ReactContext
 import com.facebook.react.bridge.ReactTestHelper
 import com.facebook.react.bridge.WritableMap
 import com.facebook.react.internal.featureflags.ReactNativeFeatureFlagsForTests
 import com.facebook.react.uimanager.DisplayMetricsHolder
+import com.facebook.react.views.view.isEdgeToEdgeFeatureFlagOn
 import com.facebook.testutils.shadows.ShadowNativeLoader
 import com.facebook.testutils.shadows.ShadowNativeMap
 import com.facebook.testutils.shadows.ShadowReadableNativeMap
@@ -33,6 +44,7 @@ import org.mockito.ArgumentMatchers
 import org.mockito.MockedStatic
 import org.mockito.Mockito.mockStatic
 import org.mockito.kotlin.doReturn
+import org.mockito.kotlin.mock
 import org.mockito.kotlin.spy
 import org.mockito.kotlin.times
 import org.mockito.kotlin.verify
@@ -80,6 +92,7 @@ class DeviceInfoModuleTest : TestCase() {
   @After
   fun teardown() {
     displayMetricsHolder.close()
+    isEdgeToEdgeFeatureFlagOn = false
   }
 
   @Test
@@ -150,10 +163,88 @@ class DeviceInfoModuleTest : TestCase() {
     assertThat(windowMap.hasKey("densityDpi")).isTrue()
   }
 
+  @Test
+  fun getWindowDisplayMetrics_usesBoundsWhenEdgeToEdgeOn() {
+    isEdgeToEdgeFeatureFlagOn = true
+
+    val activity = mock<Activity>()
+    doReturn(activity).whenever(reactContext).currentActivity
+
+    val bounds = Rect(0, 0, 1080, 2400)
+    val calculator = mockCalculator(activity, bounds)
+
+    withWindowMetricsCalculator(calculator) {
+      val metrics = deviceInfoModule.getWindowDisplayMetrics()
+      assertThat(metrics.widthPixels).isEqualTo(bounds.width())
+      assertThat(metrics.heightPixels).isEqualTo(bounds.height())
+    }
+  }
+
+  @Test
+  fun getWindowDisplayMetrics_subtractsSystemBarsWhenEdgeToEdgeOff() {
+    isEdgeToEdgeFeatureFlagOn = false
+
+    val window = mock<Window>()
+    val decorView = mock<View>()
+    whenever(window.decorView).thenReturn(decorView)
+    val activity = mock<Activity>()
+    whenever(activity.window).thenReturn(window)
+    doReturn(activity).whenever(reactContext).currentActivity
+
+    val bounds = Rect(0, 0, 1080, 2400)
+    val calculator = mockCalculator(activity, bounds)
+    val rootInsets = mockRootInsets(Insets.of(20, 80, 30, 100))
+
+    withWindowMetricsCalculator(calculator) {
+      mockStatic(ViewCompat::class.java).use { viewCompatStatic ->
+        viewCompatStatic
+            .`when`<WindowInsetsCompat?> { ViewCompat.getRootWindowInsets(decorView) }
+            .thenReturn(rootInsets)
+
+        val metrics = deviceInfoModule.getWindowDisplayMetrics()
+        assertThat(metrics.widthPixels).isEqualTo(bounds.width() - (20 + 30))
+        assertThat(metrics.heightPixels).isEqualTo(bounds.height() - (80 + 100))
+      }
+    }
+  }
+
   private fun givenDisplayMetricsHolderContains(fakeDisplayMetrics: WritableMap?) {
     doReturn(fakeDisplayMetrics).whenever(deviceInfoModule).getDisplayMetricsWritableMap()
   }
 
+  private fun mockCalculator(activity: Activity, bounds: Rect): WindowMetricsCalculator {
+    val windowMetrics = mock<WindowMetrics>()
+    whenever(windowMetrics.bounds).thenReturn(bounds)
+    val calculator = mock<WindowMetricsCalculator>()
+    whenever(calculator.computeCurrentWindowMetrics(activity)).thenReturn(windowMetrics)
+    return calculator
+  }
+
+  private fun mockRootInsets(insets: Insets): WindowInsetsCompat {
+    val rootInsets = mock<WindowInsetsCompat>()
+    val type = WindowInsetsCompat.Type.systemBars() or WindowInsetsCompat.Type.displayCutout()
+    whenever(rootInsets.getInsets(type)).thenReturn(insets)
+    return rootInsets
+  }
+
+  @Suppress("RestrictedApi")
+  private fun withWindowMetricsCalculator(
+      target: WindowMetricsCalculator,
+      block: () -> Unit,
+  ) {
+    WindowMetricsCalculator.overrideDecorator(
+        object : WindowMetricsCalculatorDecorator {
+          override fun decorate(calculator: WindowMetricsCalculator): WindowMetricsCalculator =
+              target
+        }
+    )
+    try {
+      block()
+    } finally {
+      WindowMetricsCalculator.reset()
+    }
+  }
+
   companion object {
     private fun verifyUpdateDimensionsEventsEmitted(
         context: ReactContext?,