coverlet.collector未将.NET MAUI项目纳入coverage.cobertura.xml的问题

问题描述 #

我有一个.NET MAUI项目和单元测试项目处于同一解决方案中，测试项目已引用MAUI项目且所有测试运行正常。但使用coverlet.collector生成的coverage.cobertura.xml文件仅包含普通.NET 6项目Service，完全未收录MAUI项目的代码覆盖率。本地Windows 10环境与ADO管道中均出现此问题，执行的测试命令为：

dotnet test --collect:"XPlat Code Coverage"

测试项目proj文件 #

<Project Sdk="Microsoft.NET.Sdk">
    <PropertyGroup>
        <TargetFramework>net6.0</TargetFramework>
        <IsPackable>false</IsPackable>
        <EnableNETAnalyzers>true</EnableNETAnalyzers>
        <Nullable>enable</Nullable>
    </PropertyGroup>
    <ItemGroup>
        <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.4.0" />
        <PackageReference Include="xunit" Version="2.4.2" />
        <PackageReference Include="xunit.runner.visualstudio" Version="2.4.5">
            <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
            <PrivateAssets>all</PrivateAssets>
        </PackageReference>
        <PackageReference Include="coverlet.collector" Version="3.2.0">
            <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
            <PrivateAssets>all</PrivateAssets>
        </PackageReference>
        <PackageReference Include="FluentAssertions" Version="6.8.0" />
        <PackageReference Include="NSubstitute" Version="4.4.0" />
    </ItemGroup>
    <ItemGroup>
      <ProjectReference Include="..\..\Source\MauiApp.Client\MauiApp.Client.csproj" />
      <ProjectReference Include="..\..\Source\Service\Service.csproj" />
    </ItemGroup>
    <ItemGroup>
      <Folder Include="Service\" />
    </ItemGroup>
</Project>

.NET MAUI项目proj文件 #

<Project Sdk="Microsoft.NET.Sdk">
    <PropertyGroup>
        <!--<TargetFrameworks>net6.0-ios;net6.0</TargetFrameworks>-->
        <TargetFrameworks>net6.0</TargetFrameworks>
        <TargetFrameworks Condition="$([MSBuild]::IsOSPlatform('windows'))">net6.0-windows10.0.19041.0;$(TargetFrameworks)</TargetFrameworks>
        <!-- Uncomment to also build the tizen app. You will need to install tizen by following this: https://github.com/Samsung/Tizen.NET -->
        <!-- <TargetFrameworks>$(TargetFrameworks);net6.0-tizen</TargetFrameworks> -->
        <OutputType Condition="'$(TargetFramework)' != 'net6.0'">Exe</OutputType>
        <RootNamespace>$(MSBuildProjectName.Replace("-", "_"))</RootNamespace>
        <UseMaui>true</UseMaui>
        <SingleProject>true</SingleProject>
        <ImplicitUsings>enable</ImplicitUsings>
        <Nullable>enable</Nullable>
        <!-- Display name -->
        <ApplicationTitle>GridSwift</ApplicationTitle>
        <!-- App Identifier -->
        <ApplicationId>someapp.gist</ApplicationId>
        <ApplicationIdGuid>CCB22D0C-6528-4C55-9BB7-2CAB312363AB</ApplicationIdGuid>
        <!-- Versions -->
        <ApplicationDisplayVersion>1.0</ApplicationDisplayVersion>
        <ApplicationVersion>1</ApplicationVersion>
        <!-- <SupportedOSPlatformVersion Condition="$([MSBuild]::GetTargetPlatformIdentifier('$(TargetFramework)')) == 'ios'">15.4</SupportedOSPlatformVersion>-->
        <SupportedOSPlatformVersion Condition="$([MSBuild]::GetTargetPlatformIdentifier('$(TargetFramework)')) == 'windows'">10.0.19041.0</SupportedOSPlatformVersion>
        <TargetPlatformMinVersion Condition="$([MSBuild]::GetTargetPlatformIdentifier('$(TargetFramework)')) == 'windows'">10.0.19041.0</TargetPlatformMinVersion>
        <DefaultLanguage>en-us</DefaultLanguage>
    </PropertyGroup>
    <PropertyGroup Condition="'$(Configuration)|$(TargetFramework)|$(Platform)'=='Debug|net6.0-windows10.0.19041.0|AnyCPU'">
      <TreatWarningsAsErrors>True</TreatWarningsAsErrors>
    </PropertyGroup>
    <PropertyGroup Condition="'$(Configuration)|$(TargetFramework)|$(Platform)'=='Release|net6.0-windows10.0.19041.0|AnyCPU'">
      <TreatWarningsAsErrors>True</TreatWarningsAsErrors>
    </PropertyGroup>
    <ItemGroup>
        <!-- App Icon -->
        <MauiIcon Include="Resources\AppIcon\appicon.svg" ForegroundFile="Resources\AppIcon\appiconfg.svg" Color="#512BD4" />
        <!-- Splash Screen -->
        <MauiSplashScreen Include="Resources\Splash\splash.svg" Color="#512BD4" BaseSize="128,128" />
        <!-- Images -->
        <MauiImage Include="Resources\Images\*" />
        <MauiImage Update="Resources\Images\dotnet_bot.svg" BaseSize="168,208" />
        <!-- Custom Fonts -->
        <MauiFont Include="Resources\Fonts\*" />
        <!-- Raw Assets (also remove the "Resources\Raw" prefix) -->
        <MauiAsset Include="Resources\Raw\**" LogicalName="%(RecursiveDir)%(Filename)%(Extension)" />
    </ItemGroup>
    <ItemGroup>
        <PackageReference Include="Microsoft.Identity.Client" Version="4.48.0" />
        <PackageReference Include="Newtonsoft.Json" Version="13.0.2" />
        <PackageReference Include="ReduxSimple" Version="3.7.0" />
    </ItemGroup>
    <ItemGroup>
      <MauiXaml Update="Views\LoginView.xaml">
        <Generator>MSBuild:Compile</Generator>
      </MauiXaml>
    </ItemGroup>
</Project>

原因分析 #

• 目标框架不匹配：MAUI项目默认编译多框架（即使注释了iOS目标，仍包含net6.0和Windows目标），而测试项目仅以net6.0为目标框架，coverlet无法正确关联MAUI项目的编译输出。
• 输出类型限制：MAUI项目针对非net6.0框架时，OutputType设为Exe，coverlet默认跳过可执行项目的覆盖率收集，仅处理类库类型项目。
• 版本兼容性：使用的coverlet.collector 3.2.0版本对.NET MAUI的支持不完善，早期版本对MAUI这类特殊项目的识别存在缺陷。

解决方案 #

1. 统一目标框架 #

修改MAUI项目的TargetFrameworks，强制仅编译net6.0框架，避免多框架导致的匹配问题：

<PropertyGroup>
    <!-- 替换原有多框架配置，仅保留net6.0 -->
    <TargetFrameworks>net6.0</TargetFrameworks>
    <!-- 移除Windows目标的条件编译行 -->
</PropertyGroup>

2. 强制coverlet收集可执行项目 #

在测试项目的proj文件中添加coverlet配置，明确指定要收集MAUI项目的覆盖率，并允许收集可执行项目：

<PropertyGroup>
    <!-- 保留原有属性，新增以下配置 -->
    <CollectCoverage>true</CollectCoverage>
    <IncludeTestAssembly>false</IncludeTestAssembly>
    <!-- 指定MAUI项目的程序集名称前缀 -->
    <Include>[MauiApp.Client]*</Include>
    <!-- 允许收集可执行类型项目的覆盖率 -->
    <IncludeExe>true</IncludeExe>
</PropertyGroup>

3. 升级coverlet.collector版本 #

将coverlet.collector升级到最新稳定版本（如6.0.0），新版本对.NET MAUI的支持更完善：

<PackageReference Include="coverlet.collector" Version="6.0.0">
    <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
    <PrivateAssets>all</PrivateAssets>
</PackageReference>

4. 改用coverlet.msbuild替代collector #

如果collector方式仍有问题，可切换为coverlet.msbuild包，通过MSBuild参数直接控制：
首先在测试项目中添加包引用：

<PackageReference Include="coverlet.msbuild" Version="6.0.0">
    <PrivateAssets>all</PrivateAssets>
    <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
</PackageReference>

然后执行测试命令：

dotnet test /p:CollectCoverage=true /p:CoverletOutputFormat=cobertura /p:Include="[MauiApp.Client]*" /p:IncludeExe=true

内容的提问来源于stack exchange，提问作者dik1977