1 files changed, 127 insertions, 0 deletions
diff --git a/js/src/tests/non262/Array/toSpliced-dense.js b/js/src/tests/non262/Array/toSpliced-dense.js
new file mode 100644
index 0000000000..1108f1b5f8
--- /dev/null
+++ b/js/src/tests/non262/Array/toSpliced-dense.js
@@ -0,0 +1,127 @@
+// |reftest| shell-option(--enable-change-array-by-copy) skip-if(!Array.prototype.toSpliced)
+
+const startIndices = [
+  -10, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 10,
+];
+
+const deleteCounts = [
+  0, 1, 2, 3, 4, 5, 10,
+];
+
+const insertCounts = [
+  0, 1, 2, 3, 4, 5, 10,
+];
+
+const itemsList = insertCounts.map(count => {
+  return new Array(count).fill(0);
+});
+
+const arrays = [
+  // Dense no holes.
+  [],
+  [1],
+  [1,2],
+  [1,2,3],
+  [1,2,3,4],
+  [1,2,3,4,5,6,7,8],
+
+  // Dense trailing holes.
+  [,],
+  [1,,],
+  [1,2,,],
+  [1,2,3,,],
+  [1,2,3,4,,],
+  [1,2,3,4,5,6,7,8,,],
+
+  // Dense leading holes.
+  [,],
+  [,1],
+  [,1,2],
+  [,1,2,3],
+  [,1,2,3,4],
+  [,1,2,3,4,5,6,7,8],
+
+  // Dense with holes.
+  [1,,3],
+  [1,2,,4],
+  [1,,3,,5,6,,8],
+];
+
+const objects = arrays.map(array => {
+  let obj = {
+    length: array.length,
+  };
+  for (let i = 0; i < array.length; ++i) {
+    if (i in array) {
+      obj[i] = array[i];
+    }
+  }
+  return obj;
+});
+
+const objectsWithLargerDenseInitializedLength = arrays.map(array => {
+  let obj = {
+    length: array.length,
+  };
+  for (let i = 0; i < array.length; ++i) {
+    if (i in array) {
+      obj[i] = array[i];
+    }
+  }
+
+  // Add some extra dense elements after |length|.
+  for (let i = 0; i < 5; ++i) {
+    obj[array.length + i] = "extra";
+  }
+
+  return obj;
+});
+
+const thisValues = [
+  ...arrays,
+  ...objects,
+  ...objectsWithLargerDenseInitializedLength,
+];
+
+for (let thisValue of thisValues) {
+  for (let startIndex of startIndices) {
+    for (let deleteCount of deleteCounts) {
+      for (let items of itemsList) {
+        let res = Array.prototype.toSpliced.call(thisValue, startIndex, deleteCount, ...items);
+
+        // Array.prototype.toSpliced(), steps 3-6.
+        let actualStart;
+        if (startIndex < 0) {
+          actualStart = Math.max(thisValue.length + startIndex, 0);
+        } else {
+          actualStart = Math.min(startIndex, thisValue.length);
+        }
+
+        // Array.prototype.toSpliced(), step 10.
+        let actualDeleteCount = Math.min(Math.max(0, deleteCount), thisValue.length - actualStart);
+
+        let newLength = thisValue.length + items.length - actualDeleteCount;
+        assertEq(res.length, newLength);
+
+        for (let i = 0; i < actualStart; ++i) {
+          assertEq(Object.hasOwn(res, i), true);
+          assertEq(res[i], thisValue[i]);
+        }
+
+        for (let i = 0; i < items.length; ++i) {
+          assertEq(Object.hasOwn(res, actualStart + i), true);
+          assertEq(res[actualStart + i], items[i]);
+        }
+
+        for (let i = 0; i < newLength - actualStart - items.length; ++i) {
+          assertEq(Object.hasOwn(res, actualStart + items.length + i), true);
+          assertEq(res[actualStart + items.length + i],
+                   thisValue[actualStart + actualDeleteCount + i]);
+        }
+      }
+    }
+  }
+}
+
+if (typeof reportCompare === "function")
+  reportCompare(0, 0);