feat(ReadOnlySequence): GetIntLength tests

Author: aensidhe

tests/msgpack.spec.tests/ReadOnlySequence/MultipleSegments/GetIntLength.cs

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+using System;
+using System.Buffers;
+using Shouldly;
+using Xunit;
+
+namespace ProGaudi.MsgPack.Tests.ReadOnlySequence.MultipleSegments
+{
+    public class GetIntLength
+    {
+        [Theory]
+        [InlineData(new byte[0])]
+        [InlineData(new byte[] {1})]
+        [InlineData(new byte[] {byte.MaxValue, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10})]
+        public void GetIntLengthByte(byte[] data)
+        {
+            data.ToMultipleSegments().GetIntLength().ShouldBe(data.Length);
+        }
+
+        [Theory]
+        [InlineData(new int[0])]
+        [InlineData(new[] {1})]
+        [InlineData(new[] {int.MaxValue, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10})]
+        public void GetIntLengthNonByte(int[] data)
+        {
+            data.ToMultipleSegments().GetIntLength().ShouldBe(data.Length);
+        }
+
+        [Fact]
+        public void LongLength()
+        {
+            using (var megabyte = MemoryPool<byte>.Shared.Rent(1024 * 1024))
+            {
+                var memory = megabyte.Memory;
+                var desiredLength = (1 + (int.MaxValue + 1L) / memory.Length) * memory.Length;
+                desiredLength.ShouldBeGreaterThan(int.MaxValue);
+
+                var sequence = CreateReadOnlySequence(memory, desiredLength);
+                sequence.Length.ShouldBe(desiredLength);
+                var e = Should.Throw<InvalidOperationException>(() => sequence.GetIntLength());
+                e.Message.ShouldBe($@"You can't create arrays or string longer than int.MaxValue in .net. Packet length was: {desiredLength}.
+See https://blogs.msdn.microsoft.com/joshwil/2005/08/10/bigarrayt-getting-around-the-2gb-array-size-limit/");
+            }
+
+            ReadOnlySequence<byte> CreateReadOnlySequence(Memory<byte> memory, long desiredLength)
+            {
+                ReadOnlySequenceSegment<byte> end = null;
+                ReadOnlySequenceSegment<byte> current = null;
+                while (desiredLength > 0)
+                {
+                    desiredLength -= memory.Length;
+                    var next = new LongSequenceSegment<byte>(memory, desiredLength, current);
+                    current = next;
+                    end = end ?? next;
+                }
+
+                var sequence = new ReadOnlySequence<byte>(current, 0, end, end.Memory.Length);
+                return sequence;
+            }
+        }
+
+        private sealed class LongSequenceSegment<T> : ReadOnlySequenceSegment<T>
+        {
+            public LongSequenceSegment(in Memory<T> memory, long runningIndex, ReadOnlySequenceSegment<T> next)
+            {
+                Memory = memory;
+                RunningIndex = runningIndex;
+                Next = next;
+            }
+        }
+    }
+}

tests/msgpack.spec.tests/ReadOnlySequence/SingleSegment/GetIntLength.cs

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+using Shouldly;
+using Xunit;
+
+namespace ProGaudi.MsgPack.Tests.ReadOnlySequence.SingleSegment
+{
+    public class GetIntLength
+    {
+        [Theory]
+        [InlineData(new byte[0])]
+        [InlineData(new byte[] {1})]
+        [InlineData(new byte[] {byte.MaxValue, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10})]
+        public void GetIntLengthByte(byte[] data)
+        {
+            data.ToSingleSegment().GetIntLength().ShouldBe(data.Length);
+        }
+
+        [Theory]
+        [InlineData(new int[0])]
+        [InlineData(new[] {1})]
+        [InlineData(new[] {int.MaxValue, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10})]
+        public void GetIntLengthNonByte(int[] data)
+        {
+            data.ToSingleSegment().GetIntLength().ShouldBe(data.Length);
+        }
+    }
+}