From 7ea04094dc7bb83bffb18571f0382720067833fd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Sim=C3=B5es?= <jose.simoes@eclo.solutions>
Date: Tue, 9 Dec 2025 13:35:14 +0000
Subject: [PATCH] Add unit tests for ReadOnlySpan

---
 MetadataProcessor.Tests/TestNFApp/Program.cs  |   5 +
 .../TestNFApp/TestNFApp.nfproj                |   4 +-
 .../TestNFApp/TestingReadOnlySpan.cs          | 121 ++++++++++++++++++
 3 files changed, 129 insertions(+), 1 deletion(-)
 create mode 100644 MetadataProcessor.Tests/TestNFApp/TestingReadOnlySpan.cs

diff --git a/MetadataProcessor.Tests/TestNFApp/Program.cs b/MetadataProcessor.Tests/TestNFApp/Program.cs
index 87de2a74..2e6784d5 100644
--- a/MetadataProcessor.Tests/TestNFApp/Program.cs
+++ b/MetadataProcessor.Tests/TestNFApp/Program.cs
@@ -92,6 +92,11 @@ public static void Main()
             Console.WriteLine("Span<> tests");
             _ = new TestingSpan();
 
+            // testing ReadOnlySpan<>
+            Console.WriteLine("ReadOnlySpan<> tests");
+            _ = new TestingReadOnlySpan();
+
+            // 
             Console.WriteLine("Exiting TestNFApp");
         }
 
diff --git a/MetadataProcessor.Tests/TestNFApp/TestNFApp.nfproj b/MetadataProcessor.Tests/TestNFApp/TestNFApp.nfproj
index d130183e..35e252cb 100644
--- a/MetadataProcessor.Tests/TestNFApp/TestNFApp.nfproj
+++ b/MetadataProcessor.Tests/TestNFApp/TestNFApp.nfproj
@@ -15,6 +15,7 @@
     <RootNamespace>TestNFApp</RootNamespace>
     <AssemblyName>TestNFApp</AssemblyName>
     <TargetFrameworkVersion>v1.0</TargetFrameworkVersion>
+    <LangVersion>13.0</LangVersion>
   </PropertyGroup>
   <Import Project="$(NanoFrameworkProjectSystemPath)NFProjectSystem.props" Condition="Exists('$(NanoFrameworkProjectSystemPath)NFProjectSystem.props')" />
   <ItemGroup>
@@ -36,6 +37,7 @@
     <Compile Include="OneClassOverAll.cs" />
     <Compile Include="Program.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
+    <Compile Include="TestingReadOnlySpan.cs" />
     <Compile Include="TestingSpan.cs" />
     <Compile Include="TestingDestructors.cs" />
     <Compile Include="TestingDelegates.cs" />
@@ -50,4 +52,4 @@
       <ProjectConfigurationsDeclaredAsItems />
     </ProjectCapabilities>
   </ProjectExtensions>
-</Project>
\ No newline at end of file
+</Project>
diff --git a/MetadataProcessor.Tests/TestNFApp/TestingReadOnlySpan.cs b/MetadataProcessor.Tests/TestNFApp/TestingReadOnlySpan.cs
new file mode 100644
index 00000000..5ddcf369
--- /dev/null
+++ b/MetadataProcessor.Tests/TestNFApp/TestingReadOnlySpan.cs
@@ -0,0 +1,121 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using TestNFClassLibrary;
+
+namespace TestNFApp
+{
+    public class TestingReadOnlySpan
+    {
+        public TestingReadOnlySpan()
+        {
+            int length = 3;
+
+            // base type - ReadOnlySpan<int>
+            Console.WriteLine("+++ ReadOnlySpan<int> tests");
+            Console.WriteLine();
+
+            int[] numbersArray = new int[length];
+            for (int i = 0; i < length; i++)
+            {
+                numbersArray[i] = i;
+            }
+
+            ReadOnlySpan<int> numbers = new ReadOnlySpan<int>(numbersArray);
+
+            // Test indexer access (uses ref readonly modreq return type)
+            for (int i = 0; i < numbers.Length; i++)
+            {
+                Console.WriteLine($">>numbers[{i}]: {numbers[i]}");
+            }
+
+            // Test Length property
+            Console.WriteLine($">>Length: {numbers.Length}");
+
+            // Test IsEmpty property
+            Console.WriteLine($">>IsEmpty: {numbers.IsEmpty}");
+
+            // string type - ReadOnlySpan<string>
+            Console.WriteLine("+++ ReadOnlySpan<string> tests");
+            Console.WriteLine();
+
+            string[] stringsArray = new string[length];
+            for (int i = 0; i < length; i++)
+            {
+                stringsArray[i] = $"string_{i * 10}";
+            }
+
+            ReadOnlySpan<string> strings = new ReadOnlySpan<string>(stringsArray);
+
+            // Test indexer with reference types
+            for (int i = 0; i < strings.Length; i++)
+            {
+                Console.WriteLine($">>strings[{i}]: '{strings[i]}'");
+            }
+
+            // class type - ReadOnlySpan<ClassOnAnotherAssembly>
+            Console.WriteLine("+++ ReadOnlySpan<ClassOnAnotherAssembly> tests");
+            Console.WriteLine();
+
+            ClassOnAnotherAssembly[] classArray = new ClassOnAnotherAssembly[length];
+            for (int i = 0; i < length; i++)
+            {
+                classArray[i] = new ClassOnAnotherAssembly(i * 100);
+            }
+
+            ReadOnlySpan<ClassOnAnotherAssembly> spanOfClass = new ReadOnlySpan<ClassOnAnotherAssembly>(classArray);
+
+            // Test indexer with custom class (tests modreq handling)
+            for (int i = 0; i < spanOfClass.Length; i++)
+            {
+                Console.WriteLine($">>spanOfClass[{i}].DummyProperty: '{spanOfClass[i].DummyProperty}'");
+            }
+
+            // Test constructor with start and length
+            Console.WriteLine("+++ ReadOnlySpan with start/length tests");
+            Console.WriteLine();
+
+            ReadOnlySpan<int> subspan = new ReadOnlySpan<int>(numbersArray, 1, 2);
+            for (int i = 0; i < subspan.Length; i++)
+            {
+                Console.WriteLine($">>subspan[{i}]: {subspan[i]}");
+            }
+
+            // Test ToArray method
+            Console.WriteLine("+++ ReadOnlySpan.ToArray() tests");
+            Console.WriteLine();
+
+            int[] copiedArray = numbers.ToArray();
+            for (int i = 0; i < copiedArray.Length; i++)
+            {
+                Console.WriteLine($">>copiedArray[{i}]: {copiedArray[i]}");
+            }
+
+            // Test empty span
+            Console.WriteLine("+++ Empty ReadOnlySpan tests");
+            Console.WriteLine();
+
+            ReadOnlySpan<int> emptySpan = new ReadOnlySpan<int>(new int[0]);
+            Console.WriteLine($">>emptySpan.IsEmpty: {emptySpan.IsEmpty}");
+            Console.WriteLine($">>emptySpan.Length: {emptySpan.Length}");
+
+            // Test equality operators
+            Console.WriteLine("+++ ReadOnlySpan equality tests");
+            Console.WriteLine();
+
+            ReadOnlySpan<int> span1 = new ReadOnlySpan<int>(numbersArray);
+            ReadOnlySpan<int> span2 = new ReadOnlySpan<int>(numbersArray);
+            Console.WriteLine($">>span1 == span2: {span1 == span2}");
+            Console.WriteLine($">>span1 != span2: {span1 != span2}");
+
+            // Test implicit conversion from array
+            Console.WriteLine("+++ Implicit conversion tests");
+            Console.WriteLine();
+
+            ReadOnlySpan<int> implicitSpan = numbersArray;
+            Console.WriteLine($">>implicitSpan.Length: {implicitSpan.Length}");
+            Console.WriteLine($">>implicitSpan[0]: {implicitSpan[0]}");
+        }
+    }
+}