start adding some test base

src/Plugin.All.OCR.sln

@@ -22,6 +22,8 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution
 		..\README.md = ..\README.md
 	EndProjectSection
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Plugin.OCR.Maui.Tests", "..\test\Plugin.OCR.Tests\Plugin.OCR.Maui.Tests.csproj", "{6DE9A37F-8E12-4884-BB7E-970C35AB0FD6}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -36,6 +38,10 @@ Global
 		{BC8D5E54-81F7-45F1-AC48-F269DD5C95B3}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{BC8D5E54-81F7-45F1-AC48-F269DD5C95B3}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{BC8D5E54-81F7-45F1-AC48-F269DD5C95B3}.Release|Any CPU.Build.0 = Release|Any CPU
+		{6DE9A37F-8E12-4884-BB7E-970C35AB0FD6}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{6DE9A37F-8E12-4884-BB7E-970C35AB0FD6}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{6DE9A37F-8E12-4884-BB7E-970C35AB0FD6}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{6DE9A37F-8E12-4884-BB7E-970C35AB0FD6}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

test/Plugin.OCR.Tests/BaseTest.cs

@@ -0,0 +1,78 @@
+using System.Globalization;
+using Plugin.OCR.Maui.Tests.Mocks;
+
+namespace Plugin.OCR.Maui.Tests
+{
+    public abstract class BaseTest : IDisposable
+    {
+        readonly CultureInfo _defaultCulture, _defaultUiCulture;
+
+        bool _isDisposed;
+
+        protected enum TestDuration
+        {
+            Short = 2000,
+            Medium = 5000,
+            Long = 10000
+        }
+
+        protected BaseTest()
+        {
+            _defaultCulture = Thread.CurrentThread.CurrentCulture;
+            _defaultUiCulture = Thread.CurrentThread.CurrentUICulture;
+
+            DispatcherProvider.SetCurrent(new MockDispatcherProvider());
+            //DeviceDisplay.SetCurrent(null);
+        }
+
+        ~BaseTest() => Dispose(false);
+
+        public void Dispose()
+        {
+            Dispose(true);
+            GC.SuppressFinalize(this);
+        }
+
+        protected virtual void Dispose(bool isDisposing)
+        {
+            if (_isDisposed)
+            {
+                return;
+            }
+
+            Thread.CurrentThread.CurrentCulture = _defaultCulture;
+            Thread.CurrentThread.CurrentUICulture = _defaultUiCulture;
+
+            //DeviceDisplay.SetCurrent(null);
+            DispatcherProvider.SetCurrent(null);
+
+            _isDisposed = true;
+        }
+
+        protected static Task<Stream> GetStreamFromImageSource(StreamImageSource imageSource, CancellationToken token)
+            => imageSource.Stream(token);
+
+        protected static bool StreamEquals(Stream a, Stream b)
+        {
+            if (a == b)
+            {
+                return true;
+            }
+
+            if (a.Length != b.Length)
+            {
+                return false;
+            }
+
+            for (var i = 0; i < a.Length; i++)
+            {
+                if (a.ReadByte() != b.ReadByte())
+                {
+                    return false;
+                }
+            }
+
+            return true;
+        }
+    }
+}

test/Plugin.OCR.Tests/Mocks/MockDispatcherProvider.cs

@@ -0,0 +1,80 @@
+namespace Plugin.OCR.Maui.Tests.Mocks;
+
+// Inspired by https://github.com/dotnet/maui/blob/main/src/Core/tests/UnitTests/TestClasses/DispatcherStub.cs
+sealed class MockDispatcherProvider : IDispatcherProvider, IDisposable
+{
+    static readonly DispatcherMock dispatcherMock = new();
+
+    readonly ThreadLocal<IDispatcher> dispatcherInstance = new(() => dispatcherMock);
+
+    public IDispatcher GetForCurrentThread() => dispatcherInstance.Value ?? throw new InvalidOperationException();
+
+    void IDisposable.Dispose() => dispatcherInstance.Dispose();
+
+    sealed class DispatcherMock : IDispatcher
+    {
+        public DispatcherMock() => ManagedThreadId = Environment.CurrentManagedThreadId;
+
+        public bool IsDispatchRequired => false;
+
+        public int ManagedThreadId { get; }
+
+        public IDispatcherTimer CreateTimer()
+        {
+            return new DispatcherTimerStub(this);
+        }
+
+        public bool Dispatch(Action action)
+        {
+            action();
+
+            return true;
+        }
+
+        public bool DispatchDelayed(TimeSpan delay, Action action)
+        {
+            return false;
+        }
+    }
+
+    sealed class DispatcherTimerStub : IDispatcherTimer, IDisposable
+    {
+        readonly DispatcherMock dispatcher;
+
+        Timer? timer;
+
+        public DispatcherTimerStub(DispatcherMock dispatcher)
+        {
+            this.dispatcher = dispatcher;
+        }
+
+        public TimeSpan Interval { get; set; }
+
+        public bool IsRepeating { get; set; }
+
+        public bool IsRunning => timer != null;
+
+        public event EventHandler? Tick;
+
+        public void Start()
+        {
+            timer = new Timer(OnTimeout, null, Interval, IsRepeating ? Interval : Timeout.InfiniteTimeSpan);
+
+            void OnTimeout(object? state)
+            {
+                dispatcher.Dispatch(() => Tick?.Invoke(this, EventArgs.Empty));
+            }
+        }
+
+        public void Stop()
+        {
+            Dispose();
+        }
+
+        public void Dispose()
+        {
+            timer?.Dispose();
+            timer = null;
+        }
+    }
+}

test/Plugin.OCR.Tests/Plugin.OCR.Maui.Tests.csproj

@@ -0,0 +1,29 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <UseMaui>true</UseMaui>
+    <IsPackable>false</IsPackable>
+    <IsTestProject>true</IsTestProject>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.9.0" />
+<PackageReference Include="xunit" Version="2.7.0" />
+<PackageReference Include="xunit.runner.visualstudio" Version="2.5.7">
+	<IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+	<PrivateAssets>all</PrivateAssets>
+</PackageReference>
+<PackageReference Include="coverlet.collector" Version="6.0.2">
+	<IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+	<PrivateAssets>all</PrivateAssets>
+</PackageReference>
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\src\Plugin.Maui.OCR\Plugin.Maui.OCR.csproj" />
+  </ItemGroup>
+
+</Project>

test/Plugin.OCR.Tests/Usings.cs

@@ -0,0 +1 @@
+global using Xunit;