Fix unit tests native dependencies

src/Microsoft.DotNet.Wpf/tests/UnitTests/Directory.Build.props

@@ -6,4 +6,9 @@
   <PropertyGroup>
     <WpfTestsDir>$(MsBuildThisFileDirectory)</WpfTestsDir>
   </PropertyGroup>
+
+  <ItemGroup>
+    <Compile Include="$(MSBuildThisFileDirectory)Shared\ModuleInitializer.cs" />  
+  </ItemGroup>
+
 </Project>

src/Microsoft.DotNet.Wpf/tests/UnitTests/Shared/ModuleInitializer.cs

@@ -0,0 +1,24 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+using System.Runtime.Loader;
+
+internal static class ModuleInitializer
+{
+    /// <summary>
+    /// Module initializer used as a workaround for https://github.com/dotnet/runtime/issues/111825.
+    /// </summary>
+#pragma warning disable CA2255
+    [ModuleInitializer]
+#pragma warning restore CA2255
+    public static void Initialize()
+    {
+        // When a native dll fails to resolve, try loading it from the directory of the assembly loading the dll.
+        AssemblyLoadContext.Default.ResolvingUnmanagedDll += static (assembly, name) =>
+        {
+            return NativeLibrary.TryLoad(name, assembly, DllImportSearchPath.AssemblyDirectory, out nint handle) ? handle : 0;
+        };
+    }
+}