System.IO.Tests.MemoryStreamTests.MemoryStream_Write_BeyondCapacity C# (CSharp) Method

        public static void MemoryStream_Write_BeyondCapacity()
        {
            using (MemoryStream memoryStream = new MemoryStream())
            {
                long origLength = memoryStream.Length;
                byte[] bytes = new byte[10];
                for (int i = 0; i < bytes.Length; i++)
                    bytes[i] = (byte)i;
                int spanPastEnd = 5;
                memoryStream.Seek(spanPastEnd, SeekOrigin.End);
                Assert.Equal(memoryStream.Length + spanPastEnd, memoryStream.Position);

                // Test Write
                memoryStream.Write(bytes, 0, bytes.Length);
                long pos = memoryStream.Position;
                Assert.Equal(pos, origLength + spanPastEnd + bytes.Length);
                Assert.Equal(memoryStream.Length, origLength + spanPastEnd + bytes.Length);

                // Verify bytes were correct.
                memoryStream.Position = origLength;
                byte[] newData = new byte[bytes.Length + spanPastEnd];
                int n = memoryStream.Read(newData, 0, newData.Length);
                Assert.Equal(n, newData.Length);
                for (int i = 0; i < spanPastEnd; i++)
                    Assert.Equal(0, newData[i]);
                for (int i = 0; i < bytes.Length; i++)
                    Assert.Equal(bytes[i], newData[i + spanPastEnd]);
            }
        }