Add ReactViewGroupTest (#46843)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/46843

Add some simple tests for ReactViewGroup clipping logic

Changelog: [Internal]

Reviewed By: NickGerleman

Differential Revision: D63903975

fbshipit-source-id: 8ce683a4aeba2f3916a26d7b4e93b4a30227c6d5

packages/react-native/ReactAndroid/src/test/java/com/facebook/react/views/view/ReactViewGroupTest.kt

@@ -0,0 +1,79 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+package com.facebook.react.views.view
+
+import android.app.Activity
+import android.content.Context
+import android.view.View
+import android.view.ViewGroup
+import android.widget.FrameLayout
+import com.facebook.react.internal.featureflags.ReactNativeFeatureFlagsForTests
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.Before
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.robolectric.Robolectric
+import org.robolectric.RobolectricTestRunner
+
+@RunWith(RobolectricTestRunner::class)
+class ReactViewGroupTest {
+
+  private lateinit var context: Context
+
+  @Before
+  fun setUp() {
+    ReactNativeFeatureFlagsForTests.setUp()
+    context = Robolectric.buildActivity(Activity::class.java).create().get()
+  }
+
+  @Test
+  fun `View clipping - ensure allChildren properly resizes when adding views in sequence`() {
+    val rvg = ReactViewGroup(context)
+    rvg.left = 0
+    rvg.right = 100
+    rvg.top = 0
+    rvg.bottom = 100
+    FrameLayout(context).addView(rvg)
+    rvg.removeClippedSubviews = true
+    for (i in 0..20) {
+      rvg.addViewWithSubviewClippingEnabled(TestView(context, i * 10), i)
+    }
+    rvg.updateClippingRect()
+    assertThat(rvg.childCount).isEqualTo(10)
+  }
+
+  @Test
+  fun `View clipping - ensure allChildren properly resizes when adding views out of sequence`() {
+    val rvg = ReactViewGroup(context)
+    rvg.left = 0
+    rvg.right = 100
+    rvg.top = 0
+    rvg.bottom = 100
+    FrameLayout(context).addView(rvg)
+    rvg.removeClippedSubviews = true
+    for (i in 0..10) {
+      rvg.addViewWithSubviewClippingEnabled(TestView(context, i * 10), i)
+    }
+    repeat(10) { rvg.addViewWithSubviewClippingEnabled(TestView(context, 90), 10) }
+    rvg.updateClippingRect()
+    assertThat(rvg.childCount).isEqualTo(20)
+  }
+}
+
+class TestView(context: Context, yPos: Int) : View(context) {
+  init {
+    left = 0
+    right = 100
+    top = yPos
+    bottom = top + 10
+  }
+}
+
+class TestParent(context: Context) : ViewGroup(context) {
+  override fun onLayout(changed: Boolean, l: Int, t: Int, r: Int, b: Int) = Unit
+}