From 046b28f8c6c45f0e1a526a6d41a2caa60afa1777 Mon Sep 17 00:00:00 2001
From: Ynse Hoornenborg <github@ynse.nl>
Date: Fri, 29 Dec 2023 11:00:38 +0100
Subject: [PATCH] Tests for AutoExpandingMemory class

---
 .../Memory/AutoExpandingMemoryTests.cs        | 54 +++++++++++++++++++
 1 file changed, 54 insertions(+)
 create mode 100644 tests/ImageSharp.Tests/Memory/AutoExpandingMemoryTests.cs

diff --git a/tests/ImageSharp.Tests/Memory/AutoExpandingMemoryTests.cs b/tests/ImageSharp.Tests/Memory/AutoExpandingMemoryTests.cs
new file mode 100644
index 0000000000..24ed904c0d
--- /dev/null
+++ b/tests/ImageSharp.Tests/Memory/AutoExpandingMemoryTests.cs
@@ -0,0 +1,54 @@
+// Copyright (c) Six Labors.
+// Licensed under the Six Labors Split License.
+using SixLabors.ImageSharp.Memory;
+
+// ReSharper disable InconsistentNaming
+namespace SixLabors.ImageSharp.Tests.Memory;
+
+public class AutoExpandingMemoryTests
+{
+    private readonly Configuration configurtion = Configuration.Default;
+
+    [Theory]
+    [InlineData(1000, 2000)]
+    [InlineData(1000, 1000)]
+    [InlineData(200, 1000)]
+    [InlineData(200, 200)]
+    [InlineData(200, 100)]
+    public void ExpandToRequestedCapacity(int initialCapacity, int requestedCapacity)
+    {
+        AutoExpandingMemory<byte> memory = new(this.configurtion, initialCapacity);
+        Span<byte> span = memory.GetSpan(requestedCapacity);
+        Assert.Equal(requestedCapacity, span.Length);
+    }
+
+    [Theory]
+    [InlineData(1000, 2000)]
+    [InlineData(1000, 1000)]
+    [InlineData(200, 1000)]
+    [InlineData(200, 200)]
+    [InlineData(200, 100)]
+    public void KeepDataWhileExpanding(int initialCapacity, int requestedCapacity)
+    {
+        AutoExpandingMemory<byte> memory = new(this.configurtion, initialCapacity);
+        Span<byte> firstSpan = memory.GetSpan(initialCapacity);
+        firstSpan[1] = 1;
+        firstSpan[2] = 2;
+        firstSpan[3] = 3;
+        Span<byte> expandedSpan = memory.GetSpan(requestedCapacity);
+        Assert.Equal(3, firstSpan[3]);
+        Assert.Equal(firstSpan[3], expandedSpan[3]);
+    }
+
+    [Theory]
+    [InlineData(1, -1)]
+    [InlineData(1, 0)]
+    [InlineData(-2, 1)]
+    [InlineData(-2, 0)]
+    public void Guards(int initialCapacity, int requestedCapacity) =>
+        Assert.Throws<ArgumentOutOfRangeException>(() =>
+        {
+            AutoExpandingMemory<byte> memory = new(this.configurtion, initialCapacity);
+            _ = memory.GetSpan(requestedCapacity);
+        });
+}