diff --git a/src/ValueTaskSupplement/TempList.cs b/src/ValueTaskSupplement/TempList.cs
index eee46d3..ed5ef74 100644
--- a/src/ValueTaskSupplement/TempList.cs
+++ b/src/ValueTaskSupplement/TempList.cs
@@ -18,7 +18,7 @@ public void Add(T value)
         {
             if (array.Length <= index)
             {
-                var newArray = ArrayPool<T>.Shared.Rent(index);
+                var newArray = ArrayPool<T>.Shared.Rent(index * 2);
                 Array.Copy(array, newArray, index);
                 ArrayPool<T>.Shared.Return(array, true);
                 array = newArray;
diff --git a/src/ValueTaskSupplement/_InternalVisibleTo.cs b/src/ValueTaskSupplement/_InternalVisibleTo.cs
new file mode 100644
index 0000000..16f7af3
--- /dev/null
+++ b/src/ValueTaskSupplement/_InternalVisibleTo.cs
@@ -0,0 +1,3 @@
+using System.Runtime.CompilerServices;
+
+[assembly: InternalsVisibleTo("ValueTaskSupplement.Tests")]
\ No newline at end of file
diff --git a/tests/ValueTaskSupplement.Tests/TempListTest.cs b/tests/ValueTaskSupplement.Tests/TempListTest.cs
new file mode 100644
index 0000000..885a693
--- /dev/null
+++ b/tests/ValueTaskSupplement.Tests/TempListTest.cs
@@ -0,0 +1,38 @@
+using FluentAssertions;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using Xunit;
+
+namespace ValueTaskSupplement.Tests
+{
+    public class TempListTest
+    {
+        [Fact]
+        public void Foo()
+        {
+            var xs = new TempList<int>(6);
+            xs.Add(10);
+            xs.Add(20);
+            xs.Add(30);
+            xs.Add(40);
+            xs.Add(50);
+
+            xs.AsSpan().SequenceEqual(new[] { 10, 20, 30, 40, 50 }).Should().BeTrue();
+
+            xs.Dispose();
+
+            var ys = new TempList<int>(3);
+
+            foreach (var item in Enumerable.Range(1, 100))
+            {
+                ys.Add(item);
+            }
+
+            ys.AsSpan().SequenceEqual(Enumerable.Range(1, 100).ToArray()).Should().BeTrue();
+
+            ys.Dispose();
+        }
+    }
+}