This project references NuGet package(s) that are missing on this computer. The missing file is ..\packages\NUnit.3.10.1\build\NUnit.props

Question

I am encountering the error during the Build phase of an Azure Pipeline on the Azure DeveOps site. Specifically, the packages it is complaining about are:

2018-09-30T20:35:07.6022998Z
==============================================================================
2018-09-30T20:35:08.4023740Z [command]C:\Windows\system32\chcp.com 65001
2018-09-30T20:35:08.4106228Z Active code page: 65001
2018-09-30T20:35:08.4688610Z [command]"C:\Program Files\dotnet\dotnet.exe" build D:\a\1\s\ClassService.Tests\WebAPITests.csproj --configuration release
2018-09-30T20:35:08.7564734Z Microsoft (R) Build Engine version 15.8.166+gd4e8d81a88 for .NET Core
2018-09-30T20:35:08.7565155Z Copyright (C) Microsoft Corporation. All rights reserved.
2018-09-30T20:35:08.7565308Z 
2018-09-30T20:35:09.2187455Z   Nothing to do. None of the projects specified contain packages to restore.
2018-09-30T20:35:09.2600797Z D:\a\1\s\ClassService.Tests\WebAPITests.csproj(60,5): error : This project references NuGet package(s) that are missing on this computer. Use NuGet Package Restore to download them.  For more information, see http://go.microsoft.com/fwlink/?LinkID=322105. The missing file is ..\packages\NUnit.3.10.1\build\NUnit.props.
2018-09-30T20:35:09.2684158Z 
2018-09-30T20:35:09.2685014Z Build FAILED.
2018-09-30T20:35:09.2685593Z 
2018-09-30T20:35:09.2685883Z D:\a\1\s\ClassService.Tests\WebAPITests.csproj(60,5): error : This project references NuGet package(s) that are missing on this computer. Use NuGet Package Restore to download them.  For more information, see http://go.microsoft.com/fwlink/?LinkID=322105. The missing file is ..\packages\NUnit.3.10.1\build\NUnit.props.
2018-09-30T20:35:09.2685950Z     0 Warning(s)
2018-09-30T20:35:09.2686808Z     1 Error(s)
2018-09-30T20:35:09.2686892Z 
2018-09-30T20:35:09.2687550Z Time Elapsed 00:00:00.45
2018-09-30T20:35:09.3022976Z ##[error]Error: C:\Program Files\dotnet\dotnet.exe failed with return code: 1
2018-09-30T20:35:09.3036637Z [command]"C:\Program Files\dotnet\dotnet.exe" build D:\a\1\s\DanceWorksStudio.MobileAppService\DanceWorksStudio.MobileAppService.csproj --configuration release

I have looked at similar questions where the solution is to perform a Nuget restore but they usually refer to a local machine or a Visual Studio installation not Visual Studio Team Services (the previous name for Azure DevOps).

In this case, the computer is a Hosted 2017 Agent in the Azure DevOps environment and I don't see how get a Nuget Restore job to execute there.

However, earlier in the log file, I do see references to where the build agent is installing the required Nunit Nuget packages:

2018-09-30T20:34:18.9378894Z        Using "RestoreTask" task from assembly "C:\Program Files\dotnet\sdk\2.1.400\NuGet.Build.Tasks.dll".
2018-09-30T20:34:18.9379005Z        Task "RestoreTask"
2018-09-30T20:34:18.9379127Z          (in) RestoreGraphItems Count '19'
2018-09-30T20:34:18.9379258Z          (in) RestoreDisableParallel 'False'
2018-09-30T20:34:18.9379370Z          (in) RestoreNoCache 'True'
2018-09-30T20:34:18.9379483Z          (in) RestoreIgnoreFailedSources 'False'
2018-09-30T20:34:18.9379610Z          (in) RestoreRecursive 'True'
2018-09-30T20:34:18.9379721Z          (in) RestoreForce 'False'
2018-09-30T20:34:18.9379834Z          (in) HideWarningsAndErrors 'False'
2018-09-30T20:34:19.0149316Z          Running restore with 2 concurrent jobs.    
2018-09-30T20:34:19.0239478Z          Reading project file D:\a\1\s\DanceWorksStudio.MobileAppService\DanceWorksStudio.MobileAppService.csproj.
2018-09-30T20:34:19.0621933Z          Restoring packages for D:\a\1\s\DanceWorksStudio.MobileAppService\DanceWorksStudio.MobileAppService.csproj...


2018-09-30T20:34:20.1980374Z            GET https://api.nuget.org/v3-flatcontainer/nunit/index.json
2018-09-30T20:34:20.2168394Z            GET https://api.nuget.org/v3-flatcontainer/nunit3testadapter/index.json
2018-09-30T20:34:28.8022324Z            GET https://api.nuget.org/v3-flatcontainer/nunit/3.10.1/nunit.3.10.1.nupkg


2018-09-30T20:34:39.7126978Z          Acquiring lock for the installation of NUnit3TestAdapter 3.10.0
2018-09-30T20:34:39.7127033Z          Acquired lock for the installation of NUnit3TestAdapter 3.10.0
2018-09-30T20:34:39.7127104Z          Installing NUnit3TestAdapter 3.10.0.

2018-09-30T20:34:39.7946703Z          Acquiring lock for the installation of NUnit 3.10.1
2018-09-30T20:34:39.7947844Z          Acquiring lock for the installation of Microsoft.AspNetCore.Http.Abstractions 1.0.3
2018-09-30T20:34:39.7950455Z          Acquired lock for the installation of NUnit 3.10.1
2018-09-30T20:34:39.7950672Z          Installing NUnit 3.10.1.

2018-09-30T20:34:43.5285313Z          Completed installation of NUnit3TestAdapter 3.10.0

2018-09-30T20:34:46.7897372Z          Completed installation of NUnit 3.10.1

Answer 1

It's a known Nuget issue

Look here

The solution is, in your test project's .csproj file, at the bottom normally, you'll find a section

<Target Name="EnsureNuGetPackageBuildImports" BeforeTargets="PrepareForBuild">
    <PropertyGroup>
      <ErrorText>This project references NuGet package(s) that are missing on this computer. Use NuGet Package Restore to download them.  For more information, see http://go.microsoft.com/fwlink/?LinkID=322105. The missing file is {0}.</ErrorText>
    </PropertyGroup>
    <Error Condition="!Exists('..\packages\NUnit.3.12.0\build\NUnit.props')" Text="$([System.String]::Format('$(ErrorText)', '..\packages\NUnit.3.12.0\build\NUnit.props'))" />
  </Target>

Delete that section.