Adding unit test to makeSpaceForHotseatMigration

Flag: NA
Bug: 318417510
Test: atest HotseatReorderUnitTest
Change-Id: If4fe388d00138b2d43693df0cf79abb16f354291
diff --git a/tests/Android.bp b/tests/Android.bp
index 310e418..ed8609e 100644
--- a/tests/Android.bp
+++ b/tests/Android.bp
@@ -176,6 +176,7 @@
     name: "launcher-testing-shared",
     srcs: [
         "multivalentTests/shared/com/android/launcher3/testing/shared/**/*.java",
+        "multivalentTests/shared/com/android/launcher3/testing/shared/**/*.kt"
     ],
     resource_dirs: [],
     manifest: "multivalentTests/shared/AndroidManifest.xml",
diff --git a/tests/multivalentTests/src/com/android/launcher3/celllayout/board/CellLayoutBoard.java b/tests/multivalentTests/src/com/android/launcher3/celllayout/board/CellLayoutBoard.java
index dbbdcf5..62f2259 100644
--- a/tests/multivalentTests/src/com/android/launcher3/celllayout/board/CellLayoutBoard.java
+++ b/tests/multivalentTests/src/com/android/launcher3/celllayout/board/CellLayoutBoard.java
@@ -66,7 +66,7 @@
     }
 
     public CellLayoutBoard(int width, int height) {
-        mWidget = new char[width + 1][height + 1];
+        mWidget = new char[width][height];
         this.mWidth = width;
         this.mHeight = height;
         for (int x = 0; x < mWidget.length; x++) {
@@ -371,8 +371,8 @@
         s.append("\n");
         maxX = Math.min(maxX, mWidget.length);
         maxY = Math.min(maxY, mWidget[0].length);
-        for (int y = 0; y <= maxY; y++) {
-            for (int x = 0; x <= maxX; x++) {
+        for (int y = 0; y < maxY; y++) {
+            for (int x = 0; x < maxX; x++) {
                 s.append(mWidget[x][y]);
             }
             s.append('\n');
diff --git a/tests/multivalentTests/src/com/android/launcher3/celllayout/testgenerator/RandomBoardGenerator.kt b/tests/multivalentTests/src/com/android/launcher3/celllayout/testgenerator/RandomBoardGenerator.kt
index 770024f..fcfb3db 100644
--- a/tests/multivalentTests/src/com/android/launcher3/celllayout/testgenerator/RandomBoardGenerator.kt
+++ b/tests/multivalentTests/src/com/android/launcher3/celllayout/testgenerator/RandomBoardGenerator.kt
@@ -27,7 +27,7 @@
      *   usually less than 100.
      * @return a randomly generated board filled with icons and widgets.
      */
-    open fun generateBoard(width: Int, height: Int, remainingEmptySpaces: Int): CellLayoutBoard? {
+    open fun generateBoard(width: Int, height: Int, remainingEmptySpaces: Int): CellLayoutBoard {
         val cellLayoutBoard = CellLayoutBoard(width, height)
         return fillBoard(cellLayoutBoard, Rect(0, 0, width, height), remainingEmptySpaces)
     }
@@ -39,8 +39,8 @@
     ): CellLayoutBoard {
         var remainingEmptySpaces = remainingEmptySpacesArg
         if (area.height() * area.width() <= 0) return board
-        val width = getRandom(1, area.width() - 1)
-        val height = getRandom(1, area.height() - 1)
+        val width = getRandom(1, area.width())
+        val height = getRandom(1, area.height())
         val x = area.left + getRandom(0, area.width() - width)
         val y = area.top + getRandom(0, area.height() - height)
         if (remainingEmptySpaces > 0) {
diff --git a/tests/src/com/android/launcher3/celllayout/HotseatReorderUnitTest.kt b/tests/src/com/android/launcher3/celllayout/HotseatReorderUnitTest.kt
new file mode 100644
index 0000000..13dfd5e
--- /dev/null
+++ b/tests/src/com/android/launcher3/celllayout/HotseatReorderUnitTest.kt
@@ -0,0 +1,179 @@
+/*
+ * Copyright (C) 2024 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
+ *
+ *      http://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.launcher3.celllayout
+
+import android.content.Context
+import android.graphics.Point
+import android.util.Log
+import android.view.View
+import androidx.core.view.get
+import androidx.test.core.app.ApplicationProvider
+import com.android.launcher3.CellLayout
+import com.android.launcher3.celllayout.board.CellLayoutBoard
+import com.android.launcher3.celllayout.board.IconPoint
+import com.android.launcher3.celllayout.board.PermutedBoardComparator
+import com.android.launcher3.celllayout.board.WidgetRect
+import com.android.launcher3.celllayout.testgenerator.RandomBoardGenerator
+import com.android.launcher3.util.ActivityContextWrapper
+import com.android.launcher3.views.DoubleShadowBubbleTextView
+import java.util.Random
+import org.junit.Assert
+import org.junit.Rule
+import org.junit.Test
+
+private class HotseatReorderTestCase(
+    val startBoard: CellLayoutBoard,
+    val endBoard: CellLayoutBoard
+) {
+    override fun toString(): String {
+        return "$startBoard#endBoard:\n$endBoard"
+    }
+}
+
+class HotseatReorderUnitTest {
+
+    private val applicationContext: Context =
+        ActivityContextWrapper(ApplicationProvider.getApplicationContext())
+
+    @JvmField @Rule var cellLayoutBuilder = UnitTestCellLayoutBuilderRule()
+
+    /**
+     * This test generates random CellLayout configurations and then try to reorder it and makes
+     * sure the result is a valid board meaning it didn't remove any widget or icon.
+     */
+    @Test
+    fun generateValidTests() {
+        val generator = Random(Companion.SEED.toLong())
+        for (i in 0 until Companion.TOTAL_OF_CASES_GENERATED) {
+            // Using a new seed so that we can replicate the same test cases.
+            val seed = generator.nextInt()
+            Log.d(Companion.TAG, "Seed = $seed")
+
+            val testCase: HotseatReorderTestCase =
+                generateRandomTestCase(RandomBoardGenerator(Random(seed.toLong())))
+            Log.d(Companion.TAG, "testCase = $testCase")
+
+            Assert.assertTrue(
+                "invalid case $i",
+                PermutedBoardComparator().compare(testCase.startBoard, testCase.endBoard) == 0
+            )
+        }
+    }
+
+    private fun addViewInCellLayout(
+        cellLayout: CellLayout,
+        cellX: Int,
+        cellY: Int,
+        spanX: Int,
+        spanY: Int,
+        isWidget: Boolean
+    ) {
+        val cell =
+            if (isWidget) View(applicationContext)
+            else DoubleShadowBubbleTextView(applicationContext)
+        cell.layoutParams = CellLayoutLayoutParams(cellX, cellY, spanX, spanY)
+        cellLayout.addViewToCellLayout(
+            cell,
+            -1,
+            cell.id,
+            cell.layoutParams as CellLayoutLayoutParams,
+            true
+        )
+    }
+
+    private fun solve(board: CellLayoutBoard): CellLayout {
+        val cl = cellLayoutBuilder.createCellLayout(board.width, board.height, false)
+        // The views have to be sorted or the result can vary
+        board.icons
+            .map(IconPoint::getCoord)
+            .sortedWith(
+                Comparator.comparing { p: Any -> (p as Point).x }
+                    .thenComparing { p: Any -> (p as Point).y }
+            )
+            .forEach { p ->
+                addViewInCellLayout(
+                    cellLayout = cl,
+                    cellX = p.x,
+                    cellY = p.y,
+                    spanX = 1,
+                    spanY = 1,
+                    isWidget = false
+                )
+            }
+        board.widgets
+            .sortedWith(
+                Comparator.comparing(WidgetRect::getCellX).thenComparing(WidgetRect::getCellY)
+            )
+            .forEach { widget ->
+                addViewInCellLayout(
+                    cl,
+                    widget.cellX,
+                    widget.cellY,
+                    widget.spanX,
+                    widget.spanY,
+                    isWidget = true
+                )
+            }
+        if (cl.makeSpaceForHotseatMigration(true)) {
+            commitTempPosition(cl)
+        }
+        return cl
+    }
+
+    private fun commitTempPosition(cellLayout: CellLayout) {
+        val count = cellLayout.shortcutsAndWidgets.childCount
+        for (i in 0 until count) {
+            val params = cellLayout.shortcutsAndWidgets[i].layoutParams as CellLayoutLayoutParams
+            params.cellX = params.tmpCellX
+            params.cellY = params.tmpCellY
+        }
+    }
+
+    private fun boardFromCellLayout(cellLayout: CellLayout): CellLayoutBoard {
+        val views = mutableListOf<View>()
+        for (i in 0 until cellLayout.shortcutsAndWidgets.childCount) {
+            views.add(cellLayout.shortcutsAndWidgets.getChildAt(i))
+        }
+        return CellLayoutTestUtils.viewsToBoard(views, cellLayout.countX, cellLayout.countY)
+    }
+
+    private fun generateRandomTestCase(
+        boardGenerator: RandomBoardGenerator
+    ): HotseatReorderTestCase {
+        val width: Int = boardGenerator.getRandom(3, Companion.MAX_BOARD_SIZE)
+        val height: Int = boardGenerator.getRandom(3, Companion.MAX_BOARD_SIZE)
+        val targetWidth: Int = boardGenerator.getRandom(1, width - 2)
+        val targetHeight: Int = boardGenerator.getRandom(1, height - 2)
+        val board: CellLayoutBoard =
+            boardGenerator.generateBoard(width, height, targetWidth * targetHeight)
+        val finishBoard: CellLayoutBoard = boardFromCellLayout(solve(board))
+        return HotseatReorderTestCase(board, finishBoard)
+    }
+
+    companion object {
+        private const val MAX_BOARD_SIZE = 13
+
+        /**
+         * There is nothing special about this numbers, the random seed is just to be able to
+         * reproduce the test cases and the height and width is a random number similar to what
+         * users expect on their devices
+         */
+        private const val SEED = -194162315
+        private const val TOTAL_OF_CASES_GENERATED = 300
+        private const val TAG = "HotseatReorderUnitTest"
+    }
+}