diff --git a/src/mono/wasm/Wasm.Build.Tests/TestAppScenarios/AppTestBase.cs b/src/mono/wasm/Wasm.Build.Tests/TestAppScenarios/AppTestBase.cs
index 444d70228b08fa..dc6fb9b490e7f3 100644
--- a/src/mono/wasm/Wasm.Build.Tests/TestAppScenarios/AppTestBase.cs
+++ b/src/mono/wasm/Wasm.Build.Tests/TestAppScenarios/AppTestBase.cs
@@ -30,6 +30,10 @@ protected void CopyTestAsset(string assetName, string generatedProjectNamePrefix
 
         LogPath = Path.Combine(s_buildEnv.LogRootPath, Id);
         Utils.DirectoryCopy(Path.Combine(BuildEnvironment.TestAssetsPath, assetName), Path.Combine(_projectDir!));
+
+        // WasmBasicTestApp consists of App + Library projects
+        if (assetName == "WasmBasicTestApp")
+            _projectDir = Path.Combine(_projectDir!, "App");
     }
 
     protected void BuildProject(string configuration)
diff --git a/src/mono/wasm/Wasm.Build.Tests/TestAppScenarios/LazyLoadingTests.cs b/src/mono/wasm/Wasm.Build.Tests/TestAppScenarios/LazyLoadingTests.cs
index d2219e9f9e50da..8f37a47e18860a 100644
--- a/src/mono/wasm/Wasm.Build.Tests/TestAppScenarios/LazyLoadingTests.cs
+++ b/src/mono/wasm/Wasm.Build.Tests/TestAppScenarios/LazyLoadingTests.cs
@@ -42,6 +42,6 @@ public async Task FailOnMissingLazyAssembly()
             BrowserQueryString: new Dictionary<string, string> { ["loadRequiredAssembly"] = "false" },
             ExpectedExitCode: 1
         ));
-        Assert.True(result.ConsoleOutput.Any(m => m.Contains("Could not load file or assembly") && m.Contains("System.Text.Json")), "The lazy loading test didn't emit expected error message");
+        Assert.True(result.ConsoleOutput.Any(m => m.Contains("Could not load file or assembly") && m.Contains("Json")), "The lazy loading test didn't emit expected error message");
     }
 }
diff --git a/src/mono/wasm/runtime/lazyLoading.ts b/src/mono/wasm/runtime/lazyLoading.ts
index 59c153a9d62365..55bcfd67101e8c 100644
--- a/src/mono/wasm/runtime/lazyLoading.ts
+++ b/src/mono/wasm/runtime/lazyLoading.ts
@@ -21,7 +21,7 @@ export async function loadLazyAssembly(assemblyNameToLoad: string): Promise<bool
         behavior: "assembly",
     };
 
-    if (loaderHelpers.loadedAssemblies.some(f => f.includes(assemblyNameToLoad))) {
+    if (loaderHelpers.loadedAssemblies.includes(assemblyNameToLoad)) {
         return false;
     }
 
diff --git a/src/mono/wasm/runtime/loader/assets.ts b/src/mono/wasm/runtime/loader/assets.ts
index 02e05b1f8a9622..8730988193ffd0 100644
--- a/src/mono/wasm/runtime/loader/assets.ts
+++ b/src/mono/wasm/runtime/loader/assets.ts
@@ -598,7 +598,7 @@ function download_resource(asset: AssetEntryInternal): LoadingResource {
         totalResources.add(asset.name!);
         response.response.then(() => {
             if (asset.behavior == "assembly") {
-                loaderHelpers.loadedAssemblies.push(asset.resolvedUrl!);
+                loaderHelpers.loadedAssemblies.push(asset.name);
             }
 
             resourcesLoaded++;
diff --git a/src/mono/wasm/testassets/WasmBasicTestApp/AppSettingsTest.cs b/src/mono/wasm/testassets/WasmBasicTestApp/App/AppSettingsTest.cs
similarity index 100%
rename from src/mono/wasm/testassets/WasmBasicTestApp/AppSettingsTest.cs
rename to src/mono/wasm/testassets/WasmBasicTestApp/App/AppSettingsTest.cs
diff --git a/src/mono/wasm/testassets/WasmBasicTestApp/Common/Program.cs b/src/mono/wasm/testassets/WasmBasicTestApp/App/Common/Program.cs
similarity index 100%
rename from src/mono/wasm/testassets/WasmBasicTestApp/Common/Program.cs
rename to src/mono/wasm/testassets/WasmBasicTestApp/App/Common/Program.cs
diff --git a/src/mono/wasm/testassets/WasmBasicTestApp/Common/TestOutput.cs b/src/mono/wasm/testassets/WasmBasicTestApp/App/Common/TestOutput.cs
similarity index 100%
rename from src/mono/wasm/testassets/WasmBasicTestApp/Common/TestOutput.cs
rename to src/mono/wasm/testassets/WasmBasicTestApp/App/Common/TestOutput.cs
diff --git a/src/mono/wasm/testassets/WasmBasicTestApp/LazyLoadingTest.cs b/src/mono/wasm/testassets/WasmBasicTestApp/App/LazyLoadingTest.cs
similarity index 91%
rename from src/mono/wasm/testassets/WasmBasicTestApp/LazyLoadingTest.cs
rename to src/mono/wasm/testassets/WasmBasicTestApp/App/LazyLoadingTest.cs
index 0d68b1216816c3..5aba6b1ee48a0f 100644
--- a/src/mono/wasm/testassets/WasmBasicTestApp/LazyLoadingTest.cs
+++ b/src/mono/wasm/testassets/WasmBasicTestApp/App/LazyLoadingTest.cs
@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using Library;
 using System;
 using System.Text.Json;
 using System.Runtime.InteropServices.JavaScript;
@@ -15,6 +16,4 @@ public static void Run()
         var text = JsonSerializer.Serialize(new Person("John", "Doe"));
         TestOutput.WriteLine(text);
     }
-
-    public record Person(string FirstName, string LastName);
 }
diff --git a/src/mono/wasm/testassets/WasmBasicTestApp/LibraryInitializerTest.cs b/src/mono/wasm/testassets/WasmBasicTestApp/App/LibraryInitializerTest.cs
similarity index 100%
rename from src/mono/wasm/testassets/WasmBasicTestApp/LibraryInitializerTest.cs
rename to src/mono/wasm/testassets/WasmBasicTestApp/App/LibraryInitializerTest.cs
diff --git a/src/mono/wasm/testassets/WasmBasicTestApp/Properties/AssemblyInfo.cs b/src/mono/wasm/testassets/WasmBasicTestApp/App/Properties/AssemblyInfo.cs
similarity index 100%
rename from src/mono/wasm/testassets/WasmBasicTestApp/Properties/AssemblyInfo.cs
rename to src/mono/wasm/testassets/WasmBasicTestApp/App/Properties/AssemblyInfo.cs
diff --git a/src/mono/wasm/testassets/WasmBasicTestApp/SatelliteAssembliesTest.cs b/src/mono/wasm/testassets/WasmBasicTestApp/App/SatelliteAssembliesTest.cs
similarity index 100%
rename from src/mono/wasm/testassets/WasmBasicTestApp/SatelliteAssembliesTest.cs
rename to src/mono/wasm/testassets/WasmBasicTestApp/App/SatelliteAssembliesTest.cs
diff --git a/src/mono/wasm/testassets/WasmBasicTestApp/WasmBasicTestApp.csproj b/src/mono/wasm/testassets/WasmBasicTestApp/App/WasmBasicTestApp.csproj
similarity index 70%
rename from src/mono/wasm/testassets/WasmBasicTestApp/WasmBasicTestApp.csproj
rename to src/mono/wasm/testassets/WasmBasicTestApp/App/WasmBasicTestApp.csproj
index 761ac6354ce861..a3b9364d4fce80 100644
--- a/src/mono/wasm/testassets/WasmBasicTestApp/WasmBasicTestApp.csproj
+++ b/src/mono/wasm/testassets/WasmBasicTestApp/App/WasmBasicTestApp.csproj
@@ -8,6 +8,10 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <BlazorWebAssemblyLazyLoad Include="System.Text.Json$(WasmAssemblyExtension)" />
+    <ProjectReference Include="..\Library\Json.csproj" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <BlazorWebAssemblyLazyLoad Include="Json$(WasmAssemblyExtension)" />
   </ItemGroup>
 </Project>
diff --git a/src/mono/wasm/testassets/WasmBasicTestApp/runtimeconfig.template.json b/src/mono/wasm/testassets/WasmBasicTestApp/App/runtimeconfig.template.json
similarity index 100%
rename from src/mono/wasm/testassets/WasmBasicTestApp/runtimeconfig.template.json
rename to src/mono/wasm/testassets/WasmBasicTestApp/App/runtimeconfig.template.json
diff --git a/src/mono/wasm/testassets/WasmBasicTestApp/words.es-ES.resx b/src/mono/wasm/testassets/WasmBasicTestApp/App/words.es-ES.resx
similarity index 100%
rename from src/mono/wasm/testassets/WasmBasicTestApp/words.es-ES.resx
rename to src/mono/wasm/testassets/WasmBasicTestApp/App/words.es-ES.resx
diff --git a/src/mono/wasm/testassets/WasmBasicTestApp/words.resx b/src/mono/wasm/testassets/WasmBasicTestApp/App/words.resx
similarity index 100%
rename from src/mono/wasm/testassets/WasmBasicTestApp/words.resx
rename to src/mono/wasm/testassets/WasmBasicTestApp/App/words.resx
diff --git a/src/mono/wasm/testassets/WasmBasicTestApp/wwwroot/WasmBasicTestApp.lib.module.js b/src/mono/wasm/testassets/WasmBasicTestApp/App/wwwroot/WasmBasicTestApp.lib.module.js
similarity index 100%
rename from src/mono/wasm/testassets/WasmBasicTestApp/wwwroot/WasmBasicTestApp.lib.module.js
rename to src/mono/wasm/testassets/WasmBasicTestApp/App/wwwroot/WasmBasicTestApp.lib.module.js
diff --git a/src/mono/wasm/testassets/WasmBasicTestApp/wwwroot/appsettings.Development.json b/src/mono/wasm/testassets/WasmBasicTestApp/App/wwwroot/appsettings.Development.json
similarity index 100%
rename from src/mono/wasm/testassets/WasmBasicTestApp/wwwroot/appsettings.Development.json
rename to src/mono/wasm/testassets/WasmBasicTestApp/App/wwwroot/appsettings.Development.json
diff --git a/src/mono/wasm/testassets/WasmBasicTestApp/wwwroot/appsettings.Production.json b/src/mono/wasm/testassets/WasmBasicTestApp/App/wwwroot/appsettings.Production.json
similarity index 100%
rename from src/mono/wasm/testassets/WasmBasicTestApp/wwwroot/appsettings.Production.json
rename to src/mono/wasm/testassets/WasmBasicTestApp/App/wwwroot/appsettings.Production.json
diff --git a/src/mono/wasm/testassets/WasmBasicTestApp/wwwroot/appsettings.json b/src/mono/wasm/testassets/WasmBasicTestApp/App/wwwroot/appsettings.json
similarity index 100%
rename from src/mono/wasm/testassets/WasmBasicTestApp/wwwroot/appsettings.json
rename to src/mono/wasm/testassets/WasmBasicTestApp/App/wwwroot/appsettings.json
diff --git a/src/mono/wasm/testassets/WasmBasicTestApp/wwwroot/index.html b/src/mono/wasm/testassets/WasmBasicTestApp/App/wwwroot/index.html
similarity index 100%
rename from src/mono/wasm/testassets/WasmBasicTestApp/wwwroot/index.html
rename to src/mono/wasm/testassets/WasmBasicTestApp/App/wwwroot/index.html
diff --git a/src/mono/wasm/testassets/WasmBasicTestApp/wwwroot/main.js b/src/mono/wasm/testassets/WasmBasicTestApp/App/wwwroot/main.js
similarity index 97%
rename from src/mono/wasm/testassets/WasmBasicTestApp/wwwroot/main.js
rename to src/mono/wasm/testassets/WasmBasicTestApp/App/wwwroot/main.js
index 8d537cbdfb4041..076f37a62a6d87 100644
--- a/src/mono/wasm/testassets/WasmBasicTestApp/wwwroot/main.js
+++ b/src/mono/wasm/testassets/WasmBasicTestApp/App/wwwroot/main.js
@@ -79,7 +79,7 @@ try {
             break;
         case "LazyLoadingTest":
             if (params.get("loadRequiredAssembly") !== "false") {
-                await INTERNAL.loadLazyAssembly(`System.Text.Json${assemblyExtension}`);
+                await INTERNAL.loadLazyAssembly(`Json${assemblyExtension}`);
             }
             exports.LazyLoadingTest.Run();
             exit(0);
diff --git a/src/mono/wasm/testassets/WasmBasicTestApp/Library/Json.cs b/src/mono/wasm/testassets/WasmBasicTestApp/Library/Json.cs
new file mode 100644
index 00000000000000..cd496b96a3fc9e
--- /dev/null
+++ b/src/mono/wasm/testassets/WasmBasicTestApp/Library/Json.cs
@@ -0,0 +1,11 @@
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace Library;
+
+public record Person(string FirstName, string LastName);
+
+[JsonSerializable(typeof(Person))]
+public partial class PersonJsonSerializerContext : JsonSerializerContext
+{
+}
\ No newline at end of file
diff --git a/src/mono/wasm/testassets/WasmBasicTestApp/Library/Json.csproj b/src/mono/wasm/testassets/WasmBasicTestApp/Library/Json.csproj
new file mode 100644
index 00000000000000..87c4a405521efe
--- /dev/null
+++ b/src/mono/wasm/testassets/WasmBasicTestApp/Library/Json.csproj
@@ -0,0 +1,8 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <!-- The name of the assembly is important, one the lazy loading checks is that when System.Text.Json(.dll) is already loaded, we can lazy load Json(.dll) -->
+  <PropertyGroup>
+    <TargetFramework>net8.0</TargetFramework>
+    <OutputType>Library</OutputType>
+    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
+  </PropertyGroup>
+</Project>