Fix MemoryManager ctor, add unit and perf tests, and improve performance (#28880)

* Fix MemoryManager ctor, add unit and perf tests, and improve performance.

* Remove Dangerous Span Ctor

* Fix sort order in csproj and rename Perf.MemorySlice.cs to Perf.Memory.Slice

* Fix MemoryManager ctor and use internal span ctor to improve performance (#17452)

* Fix MemoryManager ctor, add unit and perf tests, and use internal span ctor.

* Address PR feedback (remove use of Unsafe.As and Dangerous Span Ctor)

Signed-off-by: dotnet-bot-corefx-mirror <dotnet-bot@microsoft.com>

2 files changed, 57 insertions, 0 deletions

diff --git a/src/System.Memory/tests/Memory/MemoryManager.cs b/src/System.Memory/tests/Memory/MemoryManager.cs
index 4f6f2461cf..5a6c675c72 100644
--- a/src/System.Memory/tests/Memory/MemoryManager.cs
+++ b/src/System.Memory/tests/Memory/MemoryManager.cs
@@ -28,6 +28,33 @@ namespace System.MemoryTests
         }
 
         [Fact]
+        public static void MemoryManagerCtorDefault()
+        {
+            MemoryManager<int> managerInt = default;
+            Assert.Throws<ArgumentNullException>(() => new Memory<int>(managerInt, 0, 0));
+
+            managerInt = null;
+            Assert.Throws<ArgumentNullException>(() => new Memory<int>(managerInt, 0, 0));
+
+            MemoryManager<object> managerObject = default;
+            Assert.Throws<ArgumentNullException>(() => new Memory<object>(managerObject, 0, 0));
+        }
+
+        [Fact]
+        public static void MemoryManagerCtorInvalid()
+        {
+            int[] a = { 91, 92, -93, 94 };
+            MemoryManager<int> manager = new CustomMemoryForTest<int>(a);
+            Assert.Throws<ArgumentOutOfRangeException>(() => new Memory<int>(manager, 0, -1));
+            Assert.Throws<ArgumentOutOfRangeException>(() => new Memory<int>(manager, -1, 0));
+            Assert.Throws<ArgumentOutOfRangeException>(() => new Memory<int>(manager, -1, -1));
+            Assert.Throws<ArgumentOutOfRangeException>(() => new Memory<int>(manager, -1, -1));
+            Assert.Throws<ArgumentOutOfRangeException>(() => new Memory<int>(manager, 0, a.Length + 1));
+            Assert.Throws<ArgumentOutOfRangeException>(() => new Memory<int>(manager, a.Length + 1, 0));
+            Assert.Throws<ArgumentOutOfRangeException>(() => new Memory<int>(manager, 1, a.Length));
+        }
+
+        [Fact]
         public static void ReadOnlyMemoryFromMemoryFromMemoryManagerInt()
         {
             int[] a = { 91, 92, -93, 94 };
diff --git a/src/System.Memory/tests/Memory/Span.cs b/src/System.Memory/tests/Memory/Span.cs
index 55ed001b3d..55956dd6ab 100644
--- a/src/System.Memory/tests/Memory/Span.cs
+++ b/src/System.Memory/tests/Memory/Span.cs
@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 using System.Buffers;
+using System.Runtime.InteropServices;
 using Xunit;
 
 namespace System.MemoryTests
@@ -42,6 +43,22 @@ namespace System.MemoryTests
         }
 
         [Fact]
+        public static void SpanFromCtorArrayChar()
+        {
+            char[] a = { '1', '2', '3', '4', '-' };
+            Memory<char> memory;
+
+            memory = new Memory<char>(a);
+            memory.Span.Validate('1', '2', '3', '4', '-');
+
+            memory = new Memory<char>(a, 0, a.Length);
+            memory.Span.Validate('1', '2', '3', '4', '-');
+
+            MemoryManager<char> manager = new CustomMemoryForTest<char>(a);
+            manager.Memory.Span.Validate('1', '2', '3', '4', '-');
+        }
+
+        [Fact]
         public static void SpanFromCtorArrayObject()
         {
             object o1 = new object();
@@ -60,6 +77,19 @@ namespace System.MemoryTests
         }
 
         [Fact]
+        public static void SpanFromStringAsMemory()
+        {
+            string a = "1234-";
+            ReadOnlyMemory<char> memory;
+
+            memory = a.AsMemory();
+            MemoryMarshal.AsMemory(memory).Span.Validate('1', '2', '3', '4', '-');
+
+            memory = a.AsMemory(0, a.Length);
+            MemoryMarshal.AsMemory(memory).Span.Validate('1', '2', '3', '4', '-');
+        }
+
+        [Fact]
         public static void SpanFromCtorArrayZeroLength()
         {
             int[] empty = Array.Empty<int>();