Testing Blazor Wasm Net 5 Components throws System.MissingFieldException: 'Field not found: 'Microsoft.AspNetCore.Components.RenderTree.RenderTreeFrame.FrameType'.'

[roysurles]

Describe the bug or question

• Create a new Blazor Wasm Net 5 project
• Create a xUnit UnitTest Project
• Create a unit test for the Index.razor component.
• Run the test and get exception: System.MissingFieldException: 'Field not found: 'Microsoft.AspNetCore.Components.RenderTree.RenderTreeFrame.FrameType'.' on var cut = RenderComponent<Index>();

Example: Testing the Index.razor component:

`@page "/"

<h1>Hello, world!</h1>

Welcome to your new app.

<SurveyPrompt Title="How is Blazor working for you?" />`

With this test:

`using BlazorNet5BUnit.Pages;

using Bunit;

using FluentAssertions;

using Xunit;

namespace BlazorNet5BUnit.UnitTests.Pages
{
    public class IndexTests : TestContext
    {
        [Fact]
        public void Page_Should_Render()
        {
            // Arrange & Act
            var cut = RenderComponent<Index>();

            // Assert
            cut.Find("h1").InnerHtml.Should().Be("Hello, world!");
        }
    }
}
`

Results in this output:

System.MissingFieldException: 'Field not found: 'Microsoft.AspNetCore.Components.RenderTree.RenderTreeFrame.FrameType'.'

Expected behavior: The test should succeed.

Version info: - Library version: Unit Test Project cs file

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <TargetFramework>net5.0</TargetFramework>
    <GenerateMvcApplicationPartsAssemblyAttributes>false</GenerateMvcApplicationPartsAssemblyAttributes>
    <IsPackable>false</IsPackable>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="FluentAssertions" Version="5.10.3" />
    <PackageReference Include="JustMock" Version="2020.3.1019.2" />
    <PackageReference Include="Microsoft.AspNetCore.Components" Version="5.0.0" />
    <PackageReference Include="Microsoft.AspNetCore.Components.Web" Version="5.0.0" />
    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.8.0" />
    <PackageReference Include="bunit" Version="1.0.0-beta-9" />
    <PackageReference Include="xunit" Version="2.4.1" />
    <PackageReference Include="xunit.runner.visualstudio" Version="2.4.3">
      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
      <PrivateAssets>all</PrivateAssets>
    </PackageReference>
    <PackageReference Include="coverlet.collector" Version="1.3.0">
      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
      <PrivateAssets>all</PrivateAssets>
    </PackageReference>
  </ItemGroup>

  <ItemGroup>
    <ProjectReference Include="..\BlazorNet5BUnit\BlazorNet5BUnit.csproj" />
  </ItemGroup>

</Project>

- .NET Core/Blazor version: Blazor Wasm Project cs file

<Project Sdk="Microsoft.NET.Sdk.BlazorWebAssembly">

  <PropertyGroup>
    <TargetFramework>net5.0</TargetFramework>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.AspNetCore.Components.WebAssembly" Version="5.0.0" />
    <PackageReference Include="Microsoft.AspNetCore.Components.WebAssembly.DevServer" Version="5.0.0" PrivateAssets="all" />
    <PackageReference Include="System.Net.Http.Json" Version="5.0.0" />
  </ItemGroup>

</Project>

dotnet --info `PS C:\Users\rsurles> dotnet --info .NET SDK (reflecting any global.json): Version: 5.0.100 Commit: 5044b93829

Runtime Environment: OS Name: Windows OS Version: 10.0.19041 OS Platform: Windows RID: win10-x64 Base Path: C:\Program Files\dotnet\sdk\5.0.100\

Host (useful for support): Version: 5.0.0 Commit: cf258a14b7

.NET SDKs installed: 3.1.302 [C:\Program Files\dotnet\sdk] 5.0.100 [C:\Program Files\dotnet\sdk]

.NET runtimes installed: Microsoft.AspNetCore.All 2.1.23 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All] Microsoft.AspNetCore.App 2.1.23 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 3.1.6 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 3.1.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 5.0.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.NETCore.App 2.1.23 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 3.1.6 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 3.1.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 5.0.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.WindowsDesktop.App 3.1.6 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App] Microsoft.WindowsDesktop.App 3.1.9 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App] Microsoft.WindowsDesktop.App 5.0.0 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

To install additional .NET runtimes or SDKs: https://aka.ms/dotnet-download PS C:\Users\rsurles>`

[egil]

Hi @roysurles, thanks for taking the time to report this. It should however be fixed in the latest release, that added support for .NET5, i.e. beta-11.